Genetic diversity of 54 maize landraces from southwest China was tested using bulk DNA samples and 42 microsatellite (SSR) loci distributed on 10 chromosomes of maize. A total of 256 alleles were detected among the ...Genetic diversity of 54 maize landraces from southwest China was tested using bulk DNA samples and 42 microsatellite (SSR) loci distributed on 10 chromosomes of maize. A total of 256 alleles were detected among the landraces. At each locus, the number of alleles varied from 2 to 9, with an average of 6.1. On the basis of the genetic similarity coefficients, clustering analysis separated the landraces into four groups. The landraces collected from the same region were mostly grouped together. To reveal the genetic structure and genetic diversity within landraces, 165 individuals from 11 landraces were analyzed. Individual DNA samples proved to be superior to bulk DNA samples in identifying genetic diversity of landraces. A total of 330 alleles were detected in the 11 landraces. According to the results of the individual DNA sampling analysis, estimates of the mean number of alleles ‘A’, the effective allelic number ‘Ae’, the observed heterozygosity ‘Ho’, and expected heterozygosity ‘He’ were 7.86, 3.90, 0.69, and 0.37, respectively. An obvious genetic deviation from Hardy-Weinberg expectation was observed both among and within landraces and a considerable genetic variation was revealed within rather than among landraces. In addition, genetic diversity of landraces was greater in Sichuan than in the other three regions. It can be concluded that maize landraces in southwest China were initially introduced to Sichuan and from there to adjacent areas.展开更多
Genetic diversity at Gli_1, Gli_2 and Glu_1 loci was investigated in 89 Sichuan wheat (Triticum aestivum L.) landraces by using acid polyacrylamide gel electrophoresis (APAGE) and SDS_PAGE. In these landraces, a total...Genetic diversity at Gli_1, Gli_2 and Glu_1 loci was investigated in 89 Sichuan wheat (Triticum aestivum L.) landraces by using acid polyacrylamide gel electrophoresis (APAGE) and SDS_PAGE. In these landraces, a total of 32 gliadin and 3 high_molecular_weight (HMW) glutenin patterns were observed. In total, 14, 15 and 5 alleles were identified at Gli_1, Gli_2 and Glu_1, respectively. At each locus, the alleles in higher frequency were Gli_A1a (89%), Gli_B1h (46%), Gli_D1a (65%), Gli_A2a (64%), Gli_B2j (45%), Gli_D2a (48%), Glu_A1c (99%), Glu_B1b (99%) and Glu_D1a (100%). The Nei's genetic variation index (H) of Sichuan wheat landraces was 0.370?6, varying from 0 to 0.708?7. The highest genetic diversity was found at Gli_B2 locus, while the lowest was found at Glu_D1. The genetic diversity at Gli loci was higher than that of Glu_1 loci among these landraces, but it was much lower than that of modern wheat cultivars. These results indicated a narrow genetic base of Sichuan wheat landraces. In this study, “Chengdu_guangtou” had the identical gliadin and HMW_glutenin patterns with “Chinese Spring”, further supporting the proposal that “Chinese Spring” is a strain of “Chengdu_guangtou”.展开更多
A field trial was conducted to investigate main morphological and physiological changes of different maize landraces to low-P stress at the stage of seedling. P-deficiency significantly decreased root volume, total le...A field trial was conducted to investigate main morphological and physiological changes of different maize landraces to low-P stress at the stage of seedling. P-deficiency significantly decreased root volume, total leaf area, and plant dry weight, but greatly increased density of root hairs and root top ratio. In addition, P-deficiency induced the significant enhancement of phosphorus utilization efficiency and the amount of proline, malondialdehye (MDA), acid phosphatase (APase), peroxidase (POD) and superoxide dismutase (SOD), but the significant reduction of P uptake and soluable protein content. Since P-deficiency had smaller effects on the P-tolerant maize landraces DP-44, DP-32 and DP-33 as compared with P-sensitive landraces DP-29 and DP-24, it was demonstrated that differences of tolerance to P-deficiency existed among different maize landraces. The results based on the correlation analysis showed that the economic yield of maize landraces had relationships with their morphological and physiological characteristics under P-deficiency.展开更多
The phenotypic diversity of 274 Ethiopian durum wheat accessions was analyzed, taking their geographic origins into account. The aim was to assess the extent and patterns of agronomically important phenotypic variatio...The phenotypic diversity of 274 Ethiopian durum wheat accessions was analyzed, taking their geographic origins into account. The aim was to assess the extent and patterns of agronomically important phenotypic variation across districts of origin and altitude classes for major qualitative traits using diversity index and multivariate methods. Eight qualitative and three quantitative traits were scored for 2740 plants and analyzed for diversity. The Shannon–Weaver diversity(H′) index was used to estimate phenotypic diversity. The estimated H′ ranged from monomorphic for glume hairiness to highly polymorphic for other traits. The highest(0.86) H′ was obtained for seed degree of shriveling, possibly indicating the differential responses of the genotypes to water deficit during later growth stages. With respect to district of origin, the highest(0.72) and lowest(0.44) H′ values were obtained for the Bale and SNNP districts, respectively. With respect to altitude, the highest(0.76) and lowest(0.62) H′ values were recorded for altitudes 1600–2000and > 3000 m above sea levels, respectively. Principal components analysis explained substantial variation contributed by district of origin and altitude range. Genotypes were clustered into three groups by districts of origin and altitude class, with relatively strong bootstrap values of 57 and 62 for the former and latter, respectively. It could be concluded that Ethiopian durum wheat landraces are very diverse both within and among districts of origin and altitude classes. This wealth of genetic diversity should be exploited for wheat improvement of yield and for resistance to biotic and abiotic stresses, particularly terminal drought.展开更多
Understanding genetic diversity and population structure of landraces is important in utilization of these germplasm in breeding programs. In the present study, a total of 143 core maize landraces from the South Maize...Understanding genetic diversity and population structure of landraces is important in utilization of these germplasm in breeding programs. In the present study, a total of 143 core maize landraces from the South Maize Region (SR) of China, which can represent the general profile of the genetic diversity in the landraces germplasm of SR, were genotyped by 54 DNA microsatellite markers. Totally, 517 alleles (ranging from 4 to 22) were detected among these landraces, with an average of 9.57 alleles per locus. The total gene diversity of these core landraces was 0.61, suggesting a rather higher level of genetic diversity. Analysis of population structure based on Bayesian method obtained the samilar result as the phylogeny neighbor-joining (N J) method. The results indicated that the whole set of 143 core landraces could be clustered into two distinct groups. All landraces from Guangdong, Hainan, and 15 landraces from Jiangxi were clustered into group 1, while those from the other regions of SR formed the group 2. The results from the analysis of genetic diversity showed that both of groups possessed a similar gene diversity, but group 1 possessed relatively lower mean alleles per locus (6.63) and distinct alleles (91) than group 2 (7.94 and 110, respectively). The relatively high richness of total alleles and distinct alleles preserved in the core landraces from SR suggested that all these germplasm could be useful resources in germplasm enhancement and maize breeding in China.展开更多
[Objective] The paper was to explore the causes of phosphorus(P)efficiency of rice in Yunnan Province,and to provide strategy for ecological and environmental protection.[Method]Using 703 accessions of secondary core ...[Objective] The paper was to explore the causes of phosphorus(P)efficiency of rice in Yunnan Province,and to provide strategy for ecological and environmental protection.[Method]Using 703 accessions of secondary core collections from 16 prefectures of five regions in Yunnan Province,two treatments of low available P(6.26mg/kg)versus normal P(available P 40mg/kg),and invalid P(available P 0.02 mg/kg)versus normal P(available P 70 mg/kg)were set,and zonal characteristics of phosphorus efficiency and the activation characteristics of invalid P of rice landraces were investigated.[Result] Phosphorus efficiency and the activation characteristics of invalid P in soils from rice landraces of Yunnan Province had the similar identification indexes,viz.the relative indexes of four traits(tillering ability or effective panicle,root weight,biomass,and straw weight)could be the screening indexes of gene type of secondary core collection with phosphorus efficiency,which also reflected the zonal characteristics of phosphorus efficiency and the activation characteristics of invalid P in soils of 16 prefectures among five regions.On the contrary,the relative panicle length,node length under panicle,leaf length,leaf width and plant height could only be the assistant indexes of identification for phosphorus efficiency.There were similar zonal characteristics between phosphorus efficiency and the activation characteristics of invalid P in soils of rice landraces in Yunnan Province.[Conclusion] The study had great importance to the conservation and utilization of biological diversity,which would make contribution to second green revolution of "less input,multiple output,promote health,and protect the environment".展开更多
The number of B chromosomes (Bs) in 54 maize landraces from Southwest China was tested by means of cytological observations. Nine landraces with Bs were observed. A map, showing the geographic distribution of the la...The number of B chromosomes (Bs) in 54 maize landraces from Southwest China was tested by means of cytological observations. Nine landraces with Bs were observed. A map, showing the geographic distribution of the landraces with Bs, was plotted. It was found that southeastern Sichuan Province in China was the main distribution area of the landraces with Bs in Southwest China. In order to obtain information on relationships between Bs and genetic variation, genetic diversity both among and within 11 landraces was evaluated. For each SSR marker, the number of alleles ranged from 3 to 12 with an average of 7.86, which revealed a high level of genetic diversity among maize landraces in Southwest China. Based on SSRs data, higher genetic variation was found in the landraces with 2B, and the genetic distance between the landraces with and without Bs was higher. The results together with the principal component analysis (PCA) supported the hypothesis that maize landraces in Southwest China were first introduced to the middle part of southwest Sichuan, China. At the same time, the effect of Bs on genetic variation was discussed.展开更多
Waxy maize is one of the main fresh-eating maize types,and a mutation of the waxy gene causes the waxy character of maize grains.China is rich in waxy maize landraces,and Yunnan and its surrounding areas,are the place...Waxy maize is one of the main fresh-eating maize types,and a mutation of the waxy gene causes the waxy character of maize grains.China is rich in waxy maize landraces,and Yunnan and its surrounding areas,are the place of origin and genetic diversity center of Chinese waxy maize.The six known waxy alleles of Chinese waxy maize are wx-D7,wx-D10,wx-Cin4,wx-124,wx-Reina,and wx-Xuanwei.The mutation sites of these alleles all occur in the coding region of the waxy gene,however,the mechanism by which the waxy characteristic is caused by the mutation in the regulatory region has only been reported rarely in maize.In this study,405 waxy maize landraces from Yunnan were used as materials to identify the insertion and deletion of a large sequence fragment in the upstream~3.5 kb regulatory region of the waxy gene by molecular marker detection.Three different waxy alleles were identifed in this study:wx-PIF/Harbinger,wx-hAT and wxElote2.These three types of mutations all represented transposons inserted into the regulatory region of the waxy gene.Wx-PIF/Harbinger was a 304-bp MITE class transposon insertion belonging to the PIF/Harbinger family,while wx-hAT was a 560-bp MITE class transposon insertion belonging to the hAT family,and wx-Elote2 was a 6560-bp LTR-like transposon insertion.In this study,the alleles were identifed for more than 70%of the waxy maize landraces in Yunnan,which provids a basis for the utilization of these waxy maize landraces.展开更多
Genetic diversity of 62 Sichuan wheat landraces accessions of China was investigated by agronomic traits and SSR markers. The landrace population showed the characters of higher tiller capability and more kernels/spik...Genetic diversity of 62 Sichuan wheat landraces accessions of China was investigated by agronomic traits and SSR markers. The landrace population showed the characters of higher tiller capability and more kernels/spike, especially tiller no./plant of six accessions was over 40 and kernels/spike of three accessions was more than 70. A total of 547 alleles in 124 polymorphic loci were detected with an average of 4.76 alleles per locus by 114 SSR markers. Parameters analysis indicated that the genetic diversity ranked as genome A 〉 genome B 〉 genome D, and the homoeologous groups ranked as 5〉4〉3〉1〉2〉7〉6 based on genetic richness (Ri). Furthermore, chromosomes 2A, 1B and 3D had more diversity than that of chromosomes 4A, 7A and 6B. The variation of SSR loci on chromosomes 1B, 2A, 2D, 3B, and 4B implied that, in the past, different selective pressures might have acted on different chromosome regions of these landraces. Our results suggested that Sichuan common wheat landraces is a useful genetic resource for genetic research and wheat improvement.展开更多
The Himalayan region is a known hot spot of crop diversity. Traditional varieties (usually called primitive cultivars or landraces), having withstood the rigors of time (including harsh climatic conditions as well as ...The Himalayan region is a known hot spot of crop diversity. Traditional varieties (usually called primitive cultivars or landraces), having withstood the rigors of time (including harsh climatic conditions as well as attacks of insects, pests and diseases), can still be found in crop fields in rural parts of Indian Central Himalaya (ICH). These landraces harbor many desired traits from which, for example, varieties that are tolerant/resistant to abiotic/biotic stresses could be developed. In addition to the above benefits, landraces provide a basis for food security and a more varied and interesting diet. Some landraces are also known to be of medicinal value. These, along with some lesser known hill crops, are often referred to by different names such as under exploited crops, crops for marginal lands, poor person crops, and neglected mountain crops. The Himalayan region continues to be a reservoir of a large number of landraces and cultivars whose economic and ecological potential is yet to be fully understood and/or exploited. Indians have had a history of rice cultivation since ancient times. Farmers, including tribals inhabiting the IHR, still cultivate a plethora of landraces of rice and thus directly contribute towardson-farm conservation of valuable germplasm and help in the preservation of crop diversity. The present paper looks at the on-farm conservation of rice germplasm, which is still practised in the Kumaun region of ICH.展开更多
This study was conducted to determine the performance of wheat landraces cultivated under organic conditions and to analyze their stability across diverse environments. Six wheat landraces with specific characteristic...This study was conducted to determine the performance of wheat landraces cultivated under organic conditions and to analyze their stability across diverse environments. Six wheat landraces with specific characteristics (high protein content, drought tolerance, stay green) were tested under organic growing environment. The experiments were applied in three locations (Larisa (LAR), Thessaloniki (THES), Kilkis (KIL)) for three growing seasons. The role of specific agronomic traits (stay green, lodging) and their correlation with yield components were analyzed. Stability and genotypic superiority for grain yield were determined using ANOVA and genotype × environment (GGE) biplot analysis. Furthermore, the interrelationships among wheat traits and genotype-by-trait using regression analysis, coefficient of variation and (GT)-biplot technique were studied. Significant differences were found in yield among wheat landraces tested, and also in yield components, as related to specific traits expressed into organic environment. Best varieties in terms of yield were the medium statured landraces Skliropetra and M. Argolidas, characterized by lowest weight of 1000 grains, large number of spikes per m2 meter and the highest number of grains per spike as compared to the other landraces. The statistical model GGE biplot provides useful information for experimentation of wheat landraces when grown under organic environment. It identifies clearly the ideal and representative environment for experimentation and underlines the effect of specific traits for each wheat cultivar on yield performance and stability across environments.展开更多
Rice has different colors of pericarp, such as red, white and black. Red rice pericarp is rich in proanthocyanins, which have antioxidant properties and are beneficial to human health. In the present study, we analyze...Rice has different colors of pericarp, such as red, white and black. Red rice pericarp is rich in proanthocyanins, which have antioxidant properties and are beneficial to human health. In the present study, we analyzed the red-pericarp gene Rc of 419 rice landraces in Guangxi by genome-wide association study (GWAS), and validated that the Rc gene regulated the red periearp trait in flee. By analyzing the genomie DNA of 97 red-pericarp flee eultivars, we identified two new alleles in C139 and C323. Then, the exons of Rcc'9 and Rcc were sequenced with Sanger method, and the results demonstrated that the natural mutations within Re ene resulted in the two alleles Rcc and Rcc.展开更多
[Objective] The aim of this study was to screen rice strip virus (RSV)-resistant landraces. [Method] The resistance of 119 rice landraces to rice stripe virus was identified in field spontaneously infected with sma...[Objective] The aim of this study was to screen rice strip virus (RSV)-resistant landraces. [Method] The resistance of 119 rice landraces to rice stripe virus was identified in field spontaneously infected with smal plant-hopper. [Result] There were 55 landraces resistant to rice strip disease in 56 indica rice landraces, but on-ly two resistant to rice strip disease in 63 japonica rice landraces. [Conclusion] The results revealed that there were abundant rice landscapes resistant to RSV in Chi-na, and these varieties can be used to develop more genes resistant to RSV.展开更多
Biotic and abiotic stresses are major limiting factors for high crop productivity worldwide. A landrace collection consisting of 380 durum wheat(Triticum turgidum L. var. durum) entries originating in several countrie...Biotic and abiotic stresses are major limiting factors for high crop productivity worldwide. A landrace collection consisting of 380 durum wheat(Triticum turgidum L. var. durum) entries originating in several countries along with four check varieties were evaluated for biotic stresses:yellow rust(Puccinia striiformis Westendorf f. sp. tritici) and wheat stem sawfly(WSS) Cephus cinctus Norton(Hymenoptera: Cephidae), and abiotic stresses: cold and drought. The main objectives were to(i) quantify phenotypic diversity and identify variation in the durum wheat landraces for the different stresses and(ii) characterize the agronomic profiles of landraces in reaction to the stresses. Significant changes in reactions of landraces to stresses were observed.Landraces resistant to each stress were identified and agronomically characterized.Percentage reduction due to the stresses varied from 11.4%(yellow rust) to 21.6%(cold stress) for 1000-kernel weight(TKW) and from 19.9(yellow rust) to 91.9%(cold stress) for grain yield. Landraces from Asia and Europe showed enhanced genetic potential for both grain yield and cold tolerance under highland rainfed conditions of Iran. The findings showed that TKW and yield productivity could be used to assess the response of durum wheat landraces to different stresses. In conclusion, landraces showed high levels of resistance to both biotic and abiotic stresses, and selected landraces can serve in durum wheat breeding for adaptation to cold and drought-prone environments.展开更多
Forty-four V.dahliae isolates were collected from symptomatic vascular tissues of okra plants each from a different field in eight provinces located in the eastern Mediterranean and western Anatolia regions of Turkey ...Forty-four V.dahliae isolates were collected from symptomatic vascular tissues of okra plants each from a different field in eight provinces located in the eastern Mediterranean and western Anatolia regions of Turkey during 2006-2009.Nitrate-nonutilizing(nit)mutants of V.dahliae from okra were used to determine heterokaryosis and genetic relatedness among isolates.All isolates from okra plants were grouped into two vegetative compatibility groups(VCGs)(1 and 2)and three subgroups as 1A(13.6%,6/44),2A(20.5%,9/44)and 2B(65.9%,29/44)according to international criteria.Pathogenicity tests were performed on a susceptible local okra(A.esculentus)landrace in greenhouse conditions.All isolates from VCG1A and VCG2B induced defoliation(D)and partial defoliation(PD)symptoms,respectively.Other isolates from VCG2A gave rise to typical leaf chlorosis symptoms without defoliation.The obtained data showed that the virulence level of V.dahliae isolates from okra was related to their VCG belongings.Eighteen okra landraces from diverse geographical origins were screened for resistance to VCG2B and VCG1A of V.dahliae.The results indicated that all landraces were more susceptible to highly virulent VCG1A-D pathotype displaying D or PD symptoms depending on their susceptibility levels with a mean disease severity index of 3.52 than to less virulent VCG2B-PD pathotype of V.dahliae displaying PD and ND symptoms with a mean disease severity index of 2.52.Significant differences were observed among the landraces;however,none of them exhibited a level of resistance.Okra landraces;Çorum,Hatay Has and Sanlıurfa displayed the lowest level of susceptibility or little tolerance to both D and PD pathotypes.VCG2B of PD was prevailing in the surveyed areas and VCG1A of D was the most virulent of the VCGs identified.Introduction of resistant genotypes to Turkish okra germplasm from different sources and breeding new resistant okra cultivars are critical for the sustainability of okra production.展开更多
[Objectives]The study aims to provide important reference for the breeding and research of new varieties of functional broad-shoulder bitter gourd.[Methods]8 pure varieties of local broad-shoulder bitter gourd landrac...[Objectives]The study aims to provide important reference for the breeding and research of new varieties of functional broad-shoulder bitter gourd.[Methods]8 pure varieties of local broad-shoulder bitter gourd landraces in Foshan were used as experimental materials,in which polysaccharide,cellulose and vitamin C content were measured.[Results]Among the 8 varieties of local self-selected broad-shoulder bitter gourd in Foshan,the polysaccharide content of Foxuan 6 was the highest,up to 113.78 mg/100 (g·FW),which was significantly higher than that of the other 7 varieties.The polysaccharide content of Foxuan 2 was the lowest.The cellulose content of Foxuan 8 was the highest,reaching 24.50 mg/100 (g·FW),which was significantly higher than that of the other 7 varieties.The cellulose content of Foxuan 4 was the lowest.The vitamin C content of Foxuan 5 was the highest,reaching 74.24 mg/100 (g·FW),which was significantly higher than that of the other 7 varieties.The vitamin C content of Foxuan 4 was the lowest,only 7.05 mg/100 (g·FW).In a word,there were big differences between the 8 varieties of broad-shoulder bitter gourd in terms of polysaccharide,cellulose and vitamin C content.[Conclusions]It is possible to make full use of their own quality differences and develop new varieties of functional broad-shoulder bitter gourd by means of cross combination.展开更多
[ Objective] The objective of this study was to evaluate the genetic diversity and characterization of special maize population consisting of 135 Fl fami- lies. [ Method ] In this study, association analysis was condu...[ Objective] The objective of this study was to evaluate the genetic diversity and characterization of special maize population consisting of 135 Fl fami- lies. [ Method ] In this study, association analysis was conducted in 135 F1 families derived from two maize landraces, and the efficiency of this method was evalua- ted through simulation. [ Result] Association analysis with different kinds of families showed that large population size and robust phenotypic data were required for association mapping. For all the phenotypic traits, the model controlling beth population structure and relative kinship ( Q + K) performed better than the model controlling relative kinship (K), and similarly to the model controlling population structure (Q). Across 100 simulation runs in QULINE, the average power of QTL detection for the two models were 88.64% and 83.64% respectively, and the number of false QTL was reduced from 399 with GLM model to 199 with K mod- el. Our simulation results suggested that these F1 families can be used for association analysis, and the power of the QTL detection was related to the maximum al- lele frequency (MAF)and the phenotypic variation (PVE) explained by QTL. [ Conclusion] The results from this study suggest that association analysis using the F1 families is an effective approach to study maize landraces for discovering elite genes which we are interested in from these special populations.展开更多
Productivity potentials of upland rice landraces (URLs) are continuously compromised by scanty water supply due to competing priorities for irrigations and fluctuations in agro-ecological conditions peculiar to low-in...Productivity potentials of upland rice landraces (URLs) are continuously compromised by scanty water supply due to competing priorities for irrigations and fluctuations in agro-ecological conditions peculiar to low-input farming systems. A growing demand for rice amidst decline in productive agricultural areas plunges into an urgent contribution of marginal areas critical in attaining food sufficiency among Filipino households. Agronomic performances of URLs locally found in Catanduanes province, Philippines were evaluated in a replicated trial utilizing three URLs: Kamanang [1], Kadari [2] and Bulaw [3]. The experimental set-up was closely monitored for consistent dry moisture content and zero fertilizer application. Results were significant for traditional upland landraces: Kamanang and Kadari, scored in terms of higher germination rate, increment plant height and the number of tillers during the vegetative stage. Leaf color gradations, although statistically not significant across cultivars, were suggestive of varying adaptive performance between traditional cultivars subjected to low-input system. Putative low-input responsive lines indicated by the higher survival percentage and overall agronomic responses were selected from the study site. Screened lines took part of the advance population which would be potentially able to tolerate poor soil conditions (i.e. poor storehouse of water and nutrients) especially in areas with edaphological constraints and changing rainfall distribution pattern. The development of putative drought tolerant lines among URLs forms the most economical solution implicated to areas with limited access to agricultural interventions.展开更多
The Mediterranean durum wheat landraces are genetically diverse and important sources for improving resistance to abiotic and biotic stresses and developing adapted and productive durum wheat varieties in the Mediterr...The Mediterranean durum wheat landraces are genetically diverse and important sources for improving resistance to abiotic and biotic stresses and developing adapted and productive durum wheat varieties in the Mediterranean region. To study the diversity two distant countries (MoroccoandSyria) durum landraces were studied. Fifty-one microsatellites were used as molecular markers tool to determine the genetic structure and spatial adaptation of these landraces. We used two spatially-explicit methods (Bayesian and Eigen) to determine the genetic diversity and structure of a population composed of Moroccan (98) and Syrian (90) durum wheat landraces. Non-spatial methods were also applied for comparison. A significant genetic difference was detected between the landraces originated from Morocco and Syria. Six subpopulations were revealed for each country using the Bayesian method and the Eigenanalysis, which generated PC1 and sPC1, showed similar structure. Eigenanalysis exhibited a significant global genetic structure for both countries landraces;and showed that neighboring landraces tend to have close genetic profile. The two first axes of PC1 and sPC1 had discriminated four out of the six subpopulations revealed by the Bayesian methodology. Also, our study detected the close relationship between the durum landraces from the coastal areas of Syria and the Moroccan landraces from the Atlantic coastal regions where the Phoenicians/Carthaginians had settled in Morocco. These results demonstrate the importance of using the spatial models in genetic analysis of durum wheat landraces;and also recommend the use of the easily usable Eigenanalysis to analyze the genetic diversity and structure.展开更多
Genetic diversity was characterized in a collection of 159 sorghum (Sorghum bicolor L. Moench) landraces gathered from the colder region (primarily the northeastern region) of China. A set of 41 microsatellites or sim...Genetic diversity was characterized in a collection of 159 sorghum (Sorghum bicolor L. Moench) landraces gathered from the colder region (primarily the northeastern region) of China. A set of 41 microsatellites or simple sequence repeat (SSR) markers distributed throughout the 10 chromosomes of sorghum was utilized in the analysis. Majority (40 out of 41 SSRs, 98%) of the SSR markers were polymorphic and highly informative with polymorphism information content (PIC) value ranging from 0.05 to 0.92. An estimation of genetic similarity coefficients (GSC, with values ranging from 0.42 to 0.96) revealed a range of variability in this collection of sorghum landraces. Eight clusters of accessions were identified at a cut off at 0.50 GSC and these groupings were supported by the analysis of subpopulations using Structure. This study provides evidence that Chinese landraces of sorghum exhibit moderate genetic diversity and results from cluster analysis may well aid in identification of diverse accessions that can serve as parental lines for efficient utilization and application of these germplasm into sorghum breeding programs.展开更多
基金This work was supported by the National High Technology Research and Development Program of China (No. 2004BA525B04)Changjiang Scholars and Innovative Research Team in University (No. IRTO453).
文摘Genetic diversity of 54 maize landraces from southwest China was tested using bulk DNA samples and 42 microsatellite (SSR) loci distributed on 10 chromosomes of maize. A total of 256 alleles were detected among the landraces. At each locus, the number of alleles varied from 2 to 9, with an average of 6.1. On the basis of the genetic similarity coefficients, clustering analysis separated the landraces into four groups. The landraces collected from the same region were mostly grouped together. To reveal the genetic structure and genetic diversity within landraces, 165 individuals from 11 landraces were analyzed. Individual DNA samples proved to be superior to bulk DNA samples in identifying genetic diversity of landraces. A total of 330 alleles were detected in the 11 landraces. According to the results of the individual DNA sampling analysis, estimates of the mean number of alleles ‘A’, the effective allelic number ‘Ae’, the observed heterozygosity ‘Ho’, and expected heterozygosity ‘He’ were 7.86, 3.90, 0.69, and 0.37, respectively. An obvious genetic deviation from Hardy-Weinberg expectation was observed both among and within landraces and a considerable genetic variation was revealed within rather than among landraces. In addition, genetic diversity of landraces was greater in Sichuan than in the other three regions. It can be concluded that maize landraces in southwest China were initially introduced to Sichuan and from there to adjacent areas.
文摘Genetic diversity at Gli_1, Gli_2 and Glu_1 loci was investigated in 89 Sichuan wheat (Triticum aestivum L.) landraces by using acid polyacrylamide gel electrophoresis (APAGE) and SDS_PAGE. In these landraces, a total of 32 gliadin and 3 high_molecular_weight (HMW) glutenin patterns were observed. In total, 14, 15 and 5 alleles were identified at Gli_1, Gli_2 and Glu_1, respectively. At each locus, the alleles in higher frequency were Gli_A1a (89%), Gli_B1h (46%), Gli_D1a (65%), Gli_A2a (64%), Gli_B2j (45%), Gli_D2a (48%), Glu_A1c (99%), Glu_B1b (99%) and Glu_D1a (100%). The Nei's genetic variation index (H) of Sichuan wheat landraces was 0.370?6, varying from 0 to 0.708?7. The highest genetic diversity was found at Gli_B2 locus, while the lowest was found at Glu_D1. The genetic diversity at Gli loci was higher than that of Glu_1 loci among these landraces, but it was much lower than that of modern wheat cultivars. These results indicated a narrow genetic base of Sichuan wheat landraces. In this study, “Chengdu_guangtou” had the identical gliadin and HMW_glutenin patterns with “Chinese Spring”, further supporting the proposal that “Chinese Spring” is a strain of “Chengdu_guangtou”.
文摘A field trial was conducted to investigate main morphological and physiological changes of different maize landraces to low-P stress at the stage of seedling. P-deficiency significantly decreased root volume, total leaf area, and plant dry weight, but greatly increased density of root hairs and root top ratio. In addition, P-deficiency induced the significant enhancement of phosphorus utilization efficiency and the amount of proline, malondialdehye (MDA), acid phosphatase (APase), peroxidase (POD) and superoxide dismutase (SOD), but the significant reduction of P uptake and soluable protein content. Since P-deficiency had smaller effects on the P-tolerant maize landraces DP-44, DP-32 and DP-33 as compared with P-sensitive landraces DP-29 and DP-24, it was demonstrated that differences of tolerance to P-deficiency existed among different maize landraces. The results based on the correlation analysis showed that the economic yield of maize landraces had relationships with their morphological and physiological characteristics under P-deficiency.
基金done through joint project between Mekelle University and Scuola Superiore Sant'Anna and the joint grant number is CDANR/ SSSA/42/2011The first author is further indebted to Scuola Superiore Sant'Anna, Italy for financial support given to the projectMekelle University for its support
文摘The phenotypic diversity of 274 Ethiopian durum wheat accessions was analyzed, taking their geographic origins into account. The aim was to assess the extent and patterns of agronomically important phenotypic variation across districts of origin and altitude classes for major qualitative traits using diversity index and multivariate methods. Eight qualitative and three quantitative traits were scored for 2740 plants and analyzed for diversity. The Shannon–Weaver diversity(H′) index was used to estimate phenotypic diversity. The estimated H′ ranged from monomorphic for glume hairiness to highly polymorphic for other traits. The highest(0.86) H′ was obtained for seed degree of shriveling, possibly indicating the differential responses of the genotypes to water deficit during later growth stages. With respect to district of origin, the highest(0.72) and lowest(0.44) H′ values were obtained for the Bale and SNNP districts, respectively. With respect to altitude, the highest(0.76) and lowest(0.62) H′ values were recorded for altitudes 1600–2000and > 3000 m above sea levels, respectively. Principal components analysis explained substantial variation contributed by district of origin and altitude range. Genotypes were clustered into three groups by districts of origin and altitude class, with relatively strong bootstrap values of 57 and 62 for the former and latter, respectively. It could be concluded that Ethiopian durum wheat landraces are very diverse both within and among districts of origin and altitude classes. This wealth of genetic diversity should be exploited for wheat improvement of yield and for resistance to biotic and abiotic stresses, particularly terminal drought.
基金supported by the Program for Germplasm Innovation and Utilization from the Minis-try of Agrculture of China (2006BAD13B03)Beijing Natural Science Foundation (6071003)Doctoral Foundation of Southwest University, China(SWUB2008037)
文摘Understanding genetic diversity and population structure of landraces is important in utilization of these germplasm in breeding programs. In the present study, a total of 143 core maize landraces from the South Maize Region (SR) of China, which can represent the general profile of the genetic diversity in the landraces germplasm of SR, were genotyped by 54 DNA microsatellite markers. Totally, 517 alleles (ranging from 4 to 22) were detected among these landraces, with an average of 9.57 alleles per locus. The total gene diversity of these core landraces was 0.61, suggesting a rather higher level of genetic diversity. Analysis of population structure based on Bayesian method obtained the samilar result as the phylogeny neighbor-joining (N J) method. The results indicated that the whole set of 143 core landraces could be clustered into two distinct groups. All landraces from Guangdong, Hainan, and 15 landraces from Jiangxi were clustered into group 1, while those from the other regions of SR formed the group 2. The results from the analysis of genetic diversity showed that both of groups possessed a similar gene diversity, but group 1 possessed relatively lower mean alleles per locus (6.63) and distinct alleles (91) than group 2 (7.94 and 110, respectively). The relatively high richness of total alleles and distinct alleles preserved in the core landraces from SR suggested that all these germplasm could be useful resources in germplasm enhancement and maize breeding in China.
基金Supported by National Natural Science Foundation of China(31060186)Exploitue of Emphases New Production from Yunnan Provincial Scientific and Technology Department(2010BB001)Kunming Scientific and Technology Bureau(Kunkejizi10N060204)
文摘[Objective] The paper was to explore the causes of phosphorus(P)efficiency of rice in Yunnan Province,and to provide strategy for ecological and environmental protection.[Method]Using 703 accessions of secondary core collections from 16 prefectures of five regions in Yunnan Province,two treatments of low available P(6.26mg/kg)versus normal P(available P 40mg/kg),and invalid P(available P 0.02 mg/kg)versus normal P(available P 70 mg/kg)were set,and zonal characteristics of phosphorus efficiency and the activation characteristics of invalid P of rice landraces were investigated.[Result] Phosphorus efficiency and the activation characteristics of invalid P in soils from rice landraces of Yunnan Province had the similar identification indexes,viz.the relative indexes of four traits(tillering ability or effective panicle,root weight,biomass,and straw weight)could be the screening indexes of gene type of secondary core collection with phosphorus efficiency,which also reflected the zonal characteristics of phosphorus efficiency and the activation characteristics of invalid P in soils of 16 prefectures among five regions.On the contrary,the relative panicle length,node length under panicle,leaf length,leaf width and plant height could only be the assistant indexes of identification for phosphorus efficiency.There were similar zonal characteristics between phosphorus efficiency and the activation characteristics of invalid P in soils of rice landraces in Yunnan Province.[Conclusion] The study had great importance to the conservation and utilization of biological diversity,which would make contribution to second green revolution of "less input,multiple output,promote health,and protect the environment".
文摘The number of B chromosomes (Bs) in 54 maize landraces from Southwest China was tested by means of cytological observations. Nine landraces with Bs were observed. A map, showing the geographic distribution of the landraces with Bs, was plotted. It was found that southeastern Sichuan Province in China was the main distribution area of the landraces with Bs in Southwest China. In order to obtain information on relationships between Bs and genetic variation, genetic diversity both among and within 11 landraces was evaluated. For each SSR marker, the number of alleles ranged from 3 to 12 with an average of 7.86, which revealed a high level of genetic diversity among maize landraces in Southwest China. Based on SSRs data, higher genetic variation was found in the landraces with 2B, and the genetic distance between the landraces with and without Bs was higher. The results together with the principal component analysis (PCA) supported the hypothesis that maize landraces in Southwest China were first introduced to the middle part of southwest Sichuan, China. At the same time, the effect of Bs on genetic variation was discussed.
基金supported by the National Crop Sharing and Service Platform-Yunnan sub Platform,China(NICGR2018-030)the Post-doctoral Targeted Funding of Yunnan Province,China(YRST 2018[168])。
文摘Waxy maize is one of the main fresh-eating maize types,and a mutation of the waxy gene causes the waxy character of maize grains.China is rich in waxy maize landraces,and Yunnan and its surrounding areas,are the place of origin and genetic diversity center of Chinese waxy maize.The six known waxy alleles of Chinese waxy maize are wx-D7,wx-D10,wx-Cin4,wx-124,wx-Reina,and wx-Xuanwei.The mutation sites of these alleles all occur in the coding region of the waxy gene,however,the mechanism by which the waxy characteristic is caused by the mutation in the regulatory region has only been reported rarely in maize.In this study,405 waxy maize landraces from Yunnan were used as materials to identify the insertion and deletion of a large sequence fragment in the upstream~3.5 kb regulatory region of the waxy gene by molecular marker detection.Three different waxy alleles were identifed in this study:wx-PIF/Harbinger,wx-hAT and wxElote2.These three types of mutations all represented transposons inserted into the regulatory region of the waxy gene.Wx-PIF/Harbinger was a 304-bp MITE class transposon insertion belonging to the PIF/Harbinger family,while wx-hAT was a 560-bp MITE class transposon insertion belonging to the hAT family,and wx-Elote2 was a 6560-bp LTR-like transposon insertion.In this study,the alleles were identifed for more than 70%of the waxy maize landraces in Yunnan,which provids a basis for the utilization of these waxy maize landraces.
基金supported by the National Basic Research Program of China (2011CB100100)the Program for Scientific Innovative Research Team in Sichuan, China(2011JTD0015 and 11TD005)
文摘Genetic diversity of 62 Sichuan wheat landraces accessions of China was investigated by agronomic traits and SSR markers. The landrace population showed the characters of higher tiller capability and more kernels/spike, especially tiller no./plant of six accessions was over 40 and kernels/spike of three accessions was more than 70. A total of 547 alleles in 124 polymorphic loci were detected with an average of 4.76 alleles per locus by 114 SSR markers. Parameters analysis indicated that the genetic diversity ranked as genome A 〉 genome B 〉 genome D, and the homoeologous groups ranked as 5〉4〉3〉1〉2〉7〉6 based on genetic richness (Ri). Furthermore, chromosomes 2A, 1B and 3D had more diversity than that of chromosomes 4A, 7A and 6B. The variation of SSR loci on chromosomes 1B, 2A, 2D, 3B, and 4B implied that, in the past, different selective pressures might have acted on different chromosome regions of these landraces. Our results suggested that Sichuan common wheat landraces is a useful genetic resource for genetic research and wheat improvement.
文摘The Himalayan region is a known hot spot of crop diversity. Traditional varieties (usually called primitive cultivars or landraces), having withstood the rigors of time (including harsh climatic conditions as well as attacks of insects, pests and diseases), can still be found in crop fields in rural parts of Indian Central Himalaya (ICH). These landraces harbor many desired traits from which, for example, varieties that are tolerant/resistant to abiotic/biotic stresses could be developed. In addition to the above benefits, landraces provide a basis for food security and a more varied and interesting diet. Some landraces are also known to be of medicinal value. These, along with some lesser known hill crops, are often referred to by different names such as under exploited crops, crops for marginal lands, poor person crops, and neglected mountain crops. The Himalayan region continues to be a reservoir of a large number of landraces and cultivars whose economic and ecological potential is yet to be fully understood and/or exploited. Indians have had a history of rice cultivation since ancient times. Farmers, including tribals inhabiting the IHR, still cultivate a plethora of landraces of rice and thus directly contribute towardson-farm conservation of valuable germplasm and help in the preservation of crop diversity. The present paper looks at the on-farm conservation of rice germplasm, which is still practised in the Kumaun region of ICH.
文摘This study was conducted to determine the performance of wheat landraces cultivated under organic conditions and to analyze their stability across diverse environments. Six wheat landraces with specific characteristics (high protein content, drought tolerance, stay green) were tested under organic growing environment. The experiments were applied in three locations (Larisa (LAR), Thessaloniki (THES), Kilkis (KIL)) for three growing seasons. The role of specific agronomic traits (stay green, lodging) and their correlation with yield components were analyzed. Stability and genotypic superiority for grain yield were determined using ANOVA and genotype × environment (GGE) biplot analysis. Furthermore, the interrelationships among wheat traits and genotype-by-trait using regression analysis, coefficient of variation and (GT)-biplot technique were studied. Significant differences were found in yield among wheat landraces tested, and also in yield components, as related to specific traits expressed into organic environment. Best varieties in terms of yield were the medium statured landraces Skliropetra and M. Argolidas, characterized by lowest weight of 1000 grains, large number of spikes per m2 meter and the highest number of grains per spike as compared to the other landraces. The statistical model GGE biplot provides useful information for experimentation of wheat landraces when grown under organic environment. It identifies clearly the ideal and representative environment for experimentation and underlines the effect of specific traits for each wheat cultivar on yield performance and stability across environments.
基金Supported by The National Key Research and Development Program of China(2016YFD0100101-03)Science Research and Technology Development Program of Guangxi(AB16380117)+1 种基金the Fund for Talent Team of Guangxi Academy of Agricultural Sciences(2015YT15)the Special Fund for Basic Science Research of Guangxi Academy of Agricultural Sciences(2015JZ16,2015JZ17,2017YM18)
文摘Rice has different colors of pericarp, such as red, white and black. Red rice pericarp is rich in proanthocyanins, which have antioxidant properties and are beneficial to human health. In the present study, we analyzed the red-pericarp gene Rc of 419 rice landraces in Guangxi by genome-wide association study (GWAS), and validated that the Rc gene regulated the red periearp trait in flee. By analyzing the genomie DNA of 97 red-pericarp flee eultivars, we identified two new alleles in C139 and C323. Then, the exons of Rcc'9 and Rcc were sequenced with Sanger method, and the results demonstrated that the natural mutations within Re ene resulted in the two alleles Rcc and Rcc.
文摘[Objective] The aim of this study was to screen rice strip virus (RSV)-resistant landraces. [Method] The resistance of 119 rice landraces to rice stripe virus was identified in field spontaneously infected with smal plant-hopper. [Result] There were 55 landraces resistant to rice strip disease in 56 indica rice landraces, but on-ly two resistant to rice strip disease in 63 japonica rice landraces. [Conclusion] The results revealed that there were abundant rice landscapes resistant to RSV in Chi-na, and these varieties can be used to develop more genes resistant to RSV.
基金the regional durum wheat research project of the Dryland Agricultural Research Institute(DARI)of Iransupported by the Agricultural Research and Education Organization(AREEO)
文摘Biotic and abiotic stresses are major limiting factors for high crop productivity worldwide. A landrace collection consisting of 380 durum wheat(Triticum turgidum L. var. durum) entries originating in several countries along with four check varieties were evaluated for biotic stresses:yellow rust(Puccinia striiformis Westendorf f. sp. tritici) and wheat stem sawfly(WSS) Cephus cinctus Norton(Hymenoptera: Cephidae), and abiotic stresses: cold and drought. The main objectives were to(i) quantify phenotypic diversity and identify variation in the durum wheat landraces for the different stresses and(ii) characterize the agronomic profiles of landraces in reaction to the stresses. Significant changes in reactions of landraces to stresses were observed.Landraces resistant to each stress were identified and agronomically characterized.Percentage reduction due to the stresses varied from 11.4%(yellow rust) to 21.6%(cold stress) for 1000-kernel weight(TKW) and from 19.9(yellow rust) to 91.9%(cold stress) for grain yield. Landraces from Asia and Europe showed enhanced genetic potential for both grain yield and cold tolerance under highland rainfed conditions of Iran. The findings showed that TKW and yield productivity could be used to assess the response of durum wheat landraces to different stresses. In conclusion, landraces showed high levels of resistance to both biotic and abiotic stresses, and selected landraces can serve in durum wheat breeding for adaptation to cold and drought-prone environments.
基金This work was partially supported by The Scientific and Technical Research Council of Turkey(TUBITAK Project TOVAG 104-O-578).
文摘Forty-four V.dahliae isolates were collected from symptomatic vascular tissues of okra plants each from a different field in eight provinces located in the eastern Mediterranean and western Anatolia regions of Turkey during 2006-2009.Nitrate-nonutilizing(nit)mutants of V.dahliae from okra were used to determine heterokaryosis and genetic relatedness among isolates.All isolates from okra plants were grouped into two vegetative compatibility groups(VCGs)(1 and 2)and three subgroups as 1A(13.6%,6/44),2A(20.5%,9/44)and 2B(65.9%,29/44)according to international criteria.Pathogenicity tests were performed on a susceptible local okra(A.esculentus)landrace in greenhouse conditions.All isolates from VCG1A and VCG2B induced defoliation(D)and partial defoliation(PD)symptoms,respectively.Other isolates from VCG2A gave rise to typical leaf chlorosis symptoms without defoliation.The obtained data showed that the virulence level of V.dahliae isolates from okra was related to their VCG belongings.Eighteen okra landraces from diverse geographical origins were screened for resistance to VCG2B and VCG1A of V.dahliae.The results indicated that all landraces were more susceptible to highly virulent VCG1A-D pathotype displaying D or PD symptoms depending on their susceptibility levels with a mean disease severity index of 3.52 than to less virulent VCG2B-PD pathotype of V.dahliae displaying PD and ND symptoms with a mean disease severity index of 2.52.Significant differences were observed among the landraces;however,none of them exhibited a level of resistance.Okra landraces;Çorum,Hatay Has and Sanlıurfa displayed the lowest level of susceptibility or little tolerance to both D and PD pathotypes.VCG2B of PD was prevailing in the surveyed areas and VCG1A of D was the most virulent of the VCGs identified.Introduction of resistant genotypes to Turkish okra germplasm from different sources and breeding new resistant okra cultivars are critical for the sustainability of okra production.
基金Supported by Agricultural Science and Technology Promotion Project of Foshan City in 2018-2019 "Study on Purification and Protective Cultivation Techniques of Local Characteristic Crop Varieties in Foshan"
文摘[Objectives]The study aims to provide important reference for the breeding and research of new varieties of functional broad-shoulder bitter gourd.[Methods]8 pure varieties of local broad-shoulder bitter gourd landraces in Foshan were used as experimental materials,in which polysaccharide,cellulose and vitamin C content were measured.[Results]Among the 8 varieties of local self-selected broad-shoulder bitter gourd in Foshan,the polysaccharide content of Foxuan 6 was the highest,up to 113.78 mg/100 (g·FW),which was significantly higher than that of the other 7 varieties.The polysaccharide content of Foxuan 2 was the lowest.The cellulose content of Foxuan 8 was the highest,reaching 24.50 mg/100 (g·FW),which was significantly higher than that of the other 7 varieties.The cellulose content of Foxuan 4 was the lowest.The vitamin C content of Foxuan 5 was the highest,reaching 74.24 mg/100 (g·FW),which was significantly higher than that of the other 7 varieties.The vitamin C content of Foxuan 4 was the lowest,only 7.05 mg/100 (g·FW).In a word,there were big differences between the 8 varieties of broad-shoulder bitter gourd in terms of polysaccharide,cellulose and vitamin C content.[Conclusions]It is possible to make full use of their own quality differences and develop new varieties of functional broad-shoulder bitter gourd by means of cross combination.
基金Surpported by the Key Program of Department of Education of Sichuan Province,China(12ZB097)
文摘[ Objective] The objective of this study was to evaluate the genetic diversity and characterization of special maize population consisting of 135 Fl fami- lies. [ Method ] In this study, association analysis was conducted in 135 F1 families derived from two maize landraces, and the efficiency of this method was evalua- ted through simulation. [ Result] Association analysis with different kinds of families showed that large population size and robust phenotypic data were required for association mapping. For all the phenotypic traits, the model controlling beth population structure and relative kinship ( Q + K) performed better than the model controlling relative kinship (K), and similarly to the model controlling population structure (Q). Across 100 simulation runs in QULINE, the average power of QTL detection for the two models were 88.64% and 83.64% respectively, and the number of false QTL was reduced from 399 with GLM model to 199 with K mod- el. Our simulation results suggested that these F1 families can be used for association analysis, and the power of the QTL detection was related to the maximum al- lele frequency (MAF)and the phenotypic variation (PVE) explained by QTL. [ Conclusion] The results from this study suggest that association analysis using the F1 families is an effective approach to study maize landraces for discovering elite genes which we are interested in from these special populations.
文摘Productivity potentials of upland rice landraces (URLs) are continuously compromised by scanty water supply due to competing priorities for irrigations and fluctuations in agro-ecological conditions peculiar to low-input farming systems. A growing demand for rice amidst decline in productive agricultural areas plunges into an urgent contribution of marginal areas critical in attaining food sufficiency among Filipino households. Agronomic performances of URLs locally found in Catanduanes province, Philippines were evaluated in a replicated trial utilizing three URLs: Kamanang [1], Kadari [2] and Bulaw [3]. The experimental set-up was closely monitored for consistent dry moisture content and zero fertilizer application. Results were significant for traditional upland landraces: Kamanang and Kadari, scored in terms of higher germination rate, increment plant height and the number of tillers during the vegetative stage. Leaf color gradations, although statistically not significant across cultivars, were suggestive of varying adaptive performance between traditional cultivars subjected to low-input system. Putative low-input responsive lines indicated by the higher survival percentage and overall agronomic responses were selected from the study site. Screened lines took part of the advance population which would be potentially able to tolerate poor soil conditions (i.e. poor storehouse of water and nutrients) especially in areas with edaphological constraints and changing rainfall distribution pattern. The development of putative drought tolerant lines among URLs forms the most economical solution implicated to areas with limited access to agricultural interventions.
文摘The Mediterranean durum wheat landraces are genetically diverse and important sources for improving resistance to abiotic and biotic stresses and developing adapted and productive durum wheat varieties in the Mediterranean region. To study the diversity two distant countries (MoroccoandSyria) durum landraces were studied. Fifty-one microsatellites were used as molecular markers tool to determine the genetic structure and spatial adaptation of these landraces. We used two spatially-explicit methods (Bayesian and Eigen) to determine the genetic diversity and structure of a population composed of Moroccan (98) and Syrian (90) durum wheat landraces. Non-spatial methods were also applied for comparison. A significant genetic difference was detected between the landraces originated from Morocco and Syria. Six subpopulations were revealed for each country using the Bayesian method and the Eigenanalysis, which generated PC1 and sPC1, showed similar structure. Eigenanalysis exhibited a significant global genetic structure for both countries landraces;and showed that neighboring landraces tend to have close genetic profile. The two first axes of PC1 and sPC1 had discriminated four out of the six subpopulations revealed by the Bayesian methodology. Also, our study detected the close relationship between the durum landraces from the coastal areas of Syria and the Moroccan landraces from the Atlantic coastal regions where the Phoenicians/Carthaginians had settled in Morocco. These results demonstrate the importance of using the spatial models in genetic analysis of durum wheat landraces;and also recommend the use of the easily usable Eigenanalysis to analyze the genetic diversity and structure.
文摘Genetic diversity was characterized in a collection of 159 sorghum (Sorghum bicolor L. Moench) landraces gathered from the colder region (primarily the northeastern region) of China. A set of 41 microsatellites or simple sequence repeat (SSR) markers distributed throughout the 10 chromosomes of sorghum was utilized in the analysis. Majority (40 out of 41 SSRs, 98%) of the SSR markers were polymorphic and highly informative with polymorphism information content (PIC) value ranging from 0.05 to 0.92. An estimation of genetic similarity coefficients (GSC, with values ranging from 0.42 to 0.96) revealed a range of variability in this collection of sorghum landraces. Eight clusters of accessions were identified at a cut off at 0.50 GSC and these groupings were supported by the analysis of subpopulations using Structure. This study provides evidence that Chinese landraces of sorghum exhibit moderate genetic diversity and results from cluster analysis may well aid in identification of diverse accessions that can serve as parental lines for efficient utilization and application of these germplasm into sorghum breeding programs.