Totally 26 provenance stands of 17-year-old Korean pine were selected for investigating wood properties and growth characters in Mao抏rshan Experimental Forest Farm of Northeast Forestry University in 1999. The anatom...Totally 26 provenance stands of 17-year-old Korean pine were selected for investigating wood properties and growth characters in Mao抏rshan Experimental Forest Farm of Northeast Forestry University in 1999. The anatomical property indexes, including tracheid length, tracheid diameter and wall-indiameter ratio, and the physical property indexes, such as growth ring width, late wood percentage and growth ring density, were measured for wood properties. Growth character indexes, including tree height and diameter at breast height, were also measured. The analytical results showed that there exited obviously dif-ference in wood property indexes between different provenances, which is suggested that wood properties are controlled by their genetic differences. The growth character indexes of Korean pines presented significant difference and they might also be controlled by their genetic differences. Most parameters of wood properties mainly varied in the direction of longitude, but the parameters of growth characters varied in the direction of latitude.展开更多
[Objective] The aim was to enhance specificity and efficiency of quality breeding of millet. [Method] Difference analysis, correlation analysis, principal compo- nent analysis, and path analysis were conducted on nutr...[Objective] The aim was to enhance specificity and efficiency of quality breeding of millet. [Method] Difference analysis, correlation analysis, principal compo- nent analysis, and path analysis were conducted on nutritional quality characters of 29 millet varieties. [Result] Variance coefficients of nutritional quality characters among different varieties were in descending order of crude protein 〉 crude fiber 〉 fat 〉 water 〉 total carbohydrate. The results of correlation analysis suggested that crude protein exhibited extremely significant negative correlation with total carbohydrate (correlation coefficient of -0.822 4) and significantly negative correlation with fat (correlation coefficient of -0.380 7); the rest characters showed no significant correla- tion. In addition, according to PCA and path analysis, four characters, including crude protein, fat, total carbohydrate and crude fiber, determined 97.35% of variance of nutritional quality and could be taken as references for selection of breeding ma- terials, with a determination coefficient of 1.000 0. Fat and carbohydrate were typical nutritional quality characters of breeding materials, which should be selected in low generation. However, crude protein and crude fiber should be selected for millet in high generation. [Conclusion] The research provides references for breeding of new millet varieties with high nutritional quality.展开更多
[Objective] This study aimed to characterize 124 flue-cured tobacco germplasm resources, and to provide reference for making the best use of the existing flue-cured tobacco germplasm resources. [Method] A total of 124...[Objective] This study aimed to characterize 124 flue-cured tobacco germplasm resources, and to provide reference for making the best use of the existing flue-cured tobacco germplasm resources. [Method] A total of 124 flue-cured tobacco germplasm resources were studied via field experiment and statistic analysis to investigate characteristics of their growth period, morphologic characters, main agronomic traits, and economic characters. [Result] There were significant differences among the 124 flue-cured tobacco germplasm resources in growth period, morphologic characters, main agronomic traits, and economic characters. The coefficients of variation (CV) varied in a range of 7.9%-22.5%. Among them, CV of bud stage was higher, and that of corolla length was lower. Many germplasm resources were attacked seriously by black shank disease at the end of field experiment, including those with disease index higher than 90, like Kutsaga 110, TI706, Ky 151, KM10, Longshe, Chaoxian Kangchi, Kutsaga 51E, Yongding No.1, and those with disease index among 75-90 such as Liaoyan No. 8, Lingnong No.2, Shandong Duoye, 581, Cunjingyan, KRK26, and Special 400. The tobacco root knot nematode invasion was light in some germplasm or never happened in other germplasm resources. TMV happened sporadically. CV 87, Yunyan 99, Yunyan 85, K326, Yunyan 87, Zhubuo No.1, T64 and T66 produced higher yield, production value, proportion of good leaves and sold at a higher price. Finally, we screened out the germpalsm resources with good comprehensive economic values and high disease resistance such as CV 87, Yunyan 99, Yunyan 85, K326, Yunyan 87, Zhubuo No.1, T64, T66, Honghuadajinyan, G-28, Taiyan No. 8, 77089-12, Yunyan 97, K346, V2, K149, NC567, NC297, Yunyan 201, Yunyan 203, KRK22. [Conclusion] This study provides reference for making better use of tobacco germplasm resources, and breeding new varieties.展开更多
[Objective] The aim was to explore tobacco varieties which satisfy tobacco formula and is suitable to be grown in ecotopes simultaneously. [Method] Interior and exterior qualities of tobacco were compared and identifi...[Objective] The aim was to explore tobacco varieties which satisfy tobacco formula and is suitable to be grown in ecotopes simultaneously. [Method] Interior and exterior qualities of tobacco were compared and identified based on agronomic and economic characters of tobacco in fields. [Result] Yunshai No.1 was better in both agronomic and economic characters. Specifically, the fragrance was dominated by empyreumatique and aroma; the highly-qualified variety is fragrant and sweet, with little irritation, which gives the tobacco smoke a light, mild flavor. As for Virgini- a934, economic characters were better, but agronomic characters were just ordinary. Similar to Yunshai No.l, dominated by empyreumatique and aroma, the variety was with distinctive resin and herbaceous fragrance. What's more, it tasted good with high quality and usability. Cunsanpi was ordinary in agronomic characters, and poor in economic characters, with coordinated quality and chemical composition. It is fra- grant and the smoke is clean. However, the quality was not so high and it tasted not so good. Tengruan No.2 was good in agronomic characters, but poor in eco- nomic characters, which gives delicate fragrance, but not clean enough. Waiweiba and Mijie Qinggeng neither taste well nor smell sweet, performing ordinary in agro- nomic and economic characters. Hence, the two varieties seem bad in quality and ranks poorly. [Conclusion] In terms of sensory quality, the varieties from high to low were Yunshai No.1, Virginia 934, Cunsanpi, Tengruan No.2, Waiweiba and Mijie Qinggeng.展开更多
Objective] This study was conducted to discuss growth characteristics and partial production and quality characters of different varieties, so as to provide can-didates for tobacco production as wel as a theoretical b...Objective] This study was conducted to discuss growth characteristics and partial production and quality characters of different varieties, so as to provide can-didates for tobacco production as wel as a theoretical basis for variety deployment in Guizhou. [Method] ‘K326’ was used as control, the experiment for variance analysis of growth characteristics and partial production and quality characters of dif-ferent tobacco varieties was carried out in Fengsan Town, Kaiyang County, Guizhou Province in 2015. [Result] GY8 grew faster in early stages and slower in late stages, the growth periods of GY2 (130 d) and GY5(129 d) were the longest, while those of Yun85 (121 d) and Yun87 (121 d) were the shortest; and GY2, GY5 and GY8 had larger plant heights, maximum leaf widths and maximum leaf areas, and Yun85, Yun87 and K326 showed larger stem girths and maximum leaf lengths. Yun87 exhibited lower natural incidences of diseases, while Yun85 and GY8 showed higher incidences of diseases. GY2, GY5 and GY8 had higher nicotine, total nitro-gen, K and Cl contents, while Yun85, Yun87 and K326 had higher total sugar and reducing sugar contents and higher total sugar/nicotine ratio. Yun85 and Yun87 showed better economic characters, while GY5 and GY8 showed poorer economic characters. [Conclusion] Yun85 and Yun87 have quality characters better than GY2 and GY8, field natural incidences of diseases lower than GY2 and GY8, and better economic characters, and thus could serve as candidates in future flue-cured tobac-co production in Guizhou.展开更多
[Objective] Based on the cotton variety high yielding potential, fiber quality traits, disease resistance, and early maturity characters, a cultivar registration index model was developed to simplify the tedious calcu...[Objective] Based on the cotton variety high yielding potential, fiber quality traits, disease resistance, and early maturity characters, a cultivar registration index model was developed to simplify the tedious calculation process in national cotton registration procedure, and thus to enhance the practical application of cultivar regis- tration index in cotton breeding ancl cotton recommending. [Method] By means of correlation analysis, partial correlation analysis and path analysis methods, the cor- relation of cotton main properties and their effects on cultivar registration index were explored using the dataset of national cotton regional trials in Yangtze River Valley during 1996-2013. The cultivar registration index model was constructed with step- wise regression statistical technique to ascertain the quantitative relationship of main characters with cultivar registration index, and the regional cotton trial dataset in 2013 was used to validate the model. [Result] Several characters with larger deter- minants to cultivar registration index were screened out,ie. lint yield increase ratio, pro-frost yield ratio, verticillium wilt index, fiber strength, fusarium wilt index and mi- cronaire value. The cultivar registration index model defined the functional relation- ship of cultivar registration index with the selected main characters, among which lint yield increase ratio, fiber strength and micronaire value contributed most to culti- var registration index. The model validation with regional cotton trials in 2013 indi- cated the root mean square error, RMSE was only 2.77, and the variation coeffi- cient was 6.77%, which confirmed the model prediction effect was quite perfect. [Conclusion] The developed cultivar registration index model was reliable enough to simulate the complicated scoring system in cultivar registration procedure, also sim- plified cotton registration process, and enhanced the practicability of the cultivar reg- istration index.展开更多
Rice is the staple food for more than half of the world population. The utilization of the wild abortive cytoplasmic male sterility (CMS) in 1970s has significantly raised rice yield potential. But the world's annu...Rice is the staple food for more than half of the world population. The utilization of the wild abortive cytoplasmic male sterility (CMS) in 1970s has significantly raised rice yield potential. But the world's annual rice production will have to increase 70 percent over the next 30 years, to keep up with the demends of the growing population.展开更多
In order to provide the reference of improving the nutritional quality traits in carotenoids and screening its resources of wheat varieties, 185 wheat varieties or lines were selected as materials to test the caroteno...In order to provide the reference of improving the nutritional quality traits in carotenoids and screening its resources of wheat varieties, 185 wheat varieties or lines were selected as materials to test the carotenoids content, lipoxygenase activity, whiteness, yellowness and some other quality traits of whole mill in wheat.The results showed that there were highly significant variations in lipoxygenase activity,carotenoids content, whiteness and yellowness among those sample of wheat varieties; carotenoids content was significantly and positively correlated with yellowness.Cluster analysis was performed based on carotenoids content clustered all the varieties or lines into three major groups. Additionally, carotenoids were discussed in the application of nutritional quality improvement in wheat.展开更多
An experiment was conducted on Fluvisols of Awassa for two consecutive years (2005-2006) to determine effects of planting pattern and plant density on dry matter accumulation, nodulation, protein and oil content in ...An experiment was conducted on Fluvisols of Awassa for two consecutive years (2005-2006) to determine effects of planting pattern and plant density on dry matter accumulation, nodulation, protein and oil content in early and late maturing soybean varieties. Results indicated that Awassa-95 variety produced significantly higher (P 〈 0.05) number of nodules/plant (NDN), nodule dry matter (NDM) and leaf dry matter (LDM at R2 (mid flowering) stage of soybean growth than that of variety Belessa-95). Similarly, variety Awassa-95 (45%) produced significantly higher protein content than variety Belessa-95 (40%). However, variety Belessa-95 accumulated significantly higher (P 〈 0.01) dry matter in straw, grain and total biomass at R7 (physiological maturity) stage of soybean growth than variety Awassa-95. Similarly, oil content of variety Belessa-95 (18.1%) was significantly (P 〈 0.05) higher than that of variety Awassa-95 (15.9%). Equidistant rows produced significantly higher (P 〈 0.05) NDM than either rectangular or paired rows. Moreover, soybean plants grown in both rectangular and equidistant rows produced significantly higher (P 〈 0.01) straw dry matter than those grown in paired rows; but, grain dry matter/plant (GDM) was significantly higher (P 〈 0.01) paired and rectangular rows compared to equidistant rows. Plant density also affected the per plant GDM production as it was significantly higher (P 〈 0.01) in 20 and 30 plants/m2 than higher plant densities (40 and 50 plants/m2). However, dry matter and yield components had strong negative association with protein content. In fact, strong positive correlation (R 〉 0.600) occurred between grain yield and its components with dry matter components at R2 (stem dry matter (SDM), leaf dry matter (LDM) and stem + nodule + leaf dry matter together known as TDM) and straw dry matter at R7 in both varieties. This study depicted that soybean plants that produce higher dry matter components at R2 would probably produce more straw dry matter, greater grain yield components and higher grain yield dry matter at later stages.展开更多
Maize is an important economic crop grown in Nigeria. Its production is dramatically affect by the pink stem borer--Sesamia caIamistis (Hampson, Noctuidae) and sugarcane borer--Eldana saccharina (Walker, Pyralidae...Maize is an important economic crop grown in Nigeria. Its production is dramatically affect by the pink stem borer--Sesamia caIamistis (Hampson, Noctuidae) and sugarcane borer--Eldana saccharina (Walker, Pyralidae) that are endemic in Southeastern Nigeria. In areas of stress, existing genotypes may marginally do well due to their inherent capabilities. Therefore, it is possible to find useful genes in such areas of stress, since such genes have been responsible for the survival of host crops over the years. Evaluation study was conducted for a range of agronomic characteristics and resistance attributes for 209 local maize collections from Southeastern Nigeria along with three improved check varieties. Field trials were conducted at three locations in a total of four environments in 2001. Highly significant genotypic variances as were noted in all the traits, are indicative of the magnitude of variation that exists among the genotypes, thus providing the opportunity of selection for desirable traits. Furthermore, four traits, namely, leaf feeding, ear damage, stalk lodging and yield were used from across the environments to construct a rank summation index (RSI), which was used to rank the entries for resistance to stem borers. This RSI led to the identification of 11 genotypes which represents the best 5% of the 212 genotypes in resistance ability. Genotype AMA TZBR-WC1 (from International Institute of Tropical Agriculture (IITA), Ibadan) had the best overall resistance levels, followed by genotypes SE NG-77 and SE NG-67 (from Umuahia North), SE NG-62 (from Ikwuano), SE NG-148 (from Ukwa West), SE NG-106 (from Bende), SE NG-119 (from Isiala Ngwa), SE NG-33 (from Ikwuano) and SE NG-65 (from Umuahia North).展开更多
文摘Totally 26 provenance stands of 17-year-old Korean pine were selected for investigating wood properties and growth characters in Mao抏rshan Experimental Forest Farm of Northeast Forestry University in 1999. The anatomical property indexes, including tracheid length, tracheid diameter and wall-indiameter ratio, and the physical property indexes, such as growth ring width, late wood percentage and growth ring density, were measured for wood properties. Growth character indexes, including tree height and diameter at breast height, were also measured. The analytical results showed that there exited obviously dif-ference in wood property indexes between different provenances, which is suggested that wood properties are controlled by their genetic differences. The growth character indexes of Korean pines presented significant difference and they might also be controlled by their genetic differences. Most parameters of wood properties mainly varied in the direction of longitude, but the parameters of growth characters varied in the direction of latitude.
基金Supported by Special Funds of Modern Agricultural Industry Technology System(nycytx-13)~~
文摘[Objective] The aim was to enhance specificity and efficiency of quality breeding of millet. [Method] Difference analysis, correlation analysis, principal compo- nent analysis, and path analysis were conducted on nutritional quality characters of 29 millet varieties. [Result] Variance coefficients of nutritional quality characters among different varieties were in descending order of crude protein 〉 crude fiber 〉 fat 〉 water 〉 total carbohydrate. The results of correlation analysis suggested that crude protein exhibited extremely significant negative correlation with total carbohydrate (correlation coefficient of -0.822 4) and significantly negative correlation with fat (correlation coefficient of -0.380 7); the rest characters showed no significant correla- tion. In addition, according to PCA and path analysis, four characters, including crude protein, fat, total carbohydrate and crude fiber, determined 97.35% of variance of nutritional quality and could be taken as references for selection of breeding ma- terials, with a determination coefficient of 1.000 0. Fat and carbohydrate were typical nutritional quality characters of breeding materials, which should be selected in low generation. However, crude protein and crude fiber should be selected for millet in high generation. [Conclusion] The research provides references for breeding of new millet varieties with high nutritional quality.
基金Supported by a grant from Yunnan Tobacco Company of China Tobacco Corporation(2010YN02)~~
文摘[Objective] This study aimed to characterize 124 flue-cured tobacco germplasm resources, and to provide reference for making the best use of the existing flue-cured tobacco germplasm resources. [Method] A total of 124 flue-cured tobacco germplasm resources were studied via field experiment and statistic analysis to investigate characteristics of their growth period, morphologic characters, main agronomic traits, and economic characters. [Result] There were significant differences among the 124 flue-cured tobacco germplasm resources in growth period, morphologic characters, main agronomic traits, and economic characters. The coefficients of variation (CV) varied in a range of 7.9%-22.5%. Among them, CV of bud stage was higher, and that of corolla length was lower. Many germplasm resources were attacked seriously by black shank disease at the end of field experiment, including those with disease index higher than 90, like Kutsaga 110, TI706, Ky 151, KM10, Longshe, Chaoxian Kangchi, Kutsaga 51E, Yongding No.1, and those with disease index among 75-90 such as Liaoyan No. 8, Lingnong No.2, Shandong Duoye, 581, Cunjingyan, KRK26, and Special 400. The tobacco root knot nematode invasion was light in some germplasm or never happened in other germplasm resources. TMV happened sporadically. CV 87, Yunyan 99, Yunyan 85, K326, Yunyan 87, Zhubuo No.1, T64 and T66 produced higher yield, production value, proportion of good leaves and sold at a higher price. Finally, we screened out the germpalsm resources with good comprehensive economic values and high disease resistance such as CV 87, Yunyan 99, Yunyan 85, K326, Yunyan 87, Zhubuo No.1, T64, T66, Honghuadajinyan, G-28, Taiyan No. 8, 77089-12, Yunyan 97, K346, V2, K149, NC567, NC297, Yunyan 201, Yunyan 203, KRK22. [Conclusion] This study provides reference for making better use of tobacco germplasm resources, and breeding new varieties.
基金Supported by China Tobacco Yunnan Industrial Co.,Ltd(2010YL02)~~
文摘[Objective] The aim was to explore tobacco varieties which satisfy tobacco formula and is suitable to be grown in ecotopes simultaneously. [Method] Interior and exterior qualities of tobacco were compared and identified based on agronomic and economic characters of tobacco in fields. [Result] Yunshai No.1 was better in both agronomic and economic characters. Specifically, the fragrance was dominated by empyreumatique and aroma; the highly-qualified variety is fragrant and sweet, with little irritation, which gives the tobacco smoke a light, mild flavor. As for Virgini- a934, economic characters were better, but agronomic characters were just ordinary. Similar to Yunshai No.l, dominated by empyreumatique and aroma, the variety was with distinctive resin and herbaceous fragrance. What's more, it tasted good with high quality and usability. Cunsanpi was ordinary in agronomic characters, and poor in economic characters, with coordinated quality and chemical composition. It is fra- grant and the smoke is clean. However, the quality was not so high and it tasted not so good. Tengruan No.2 was good in agronomic characters, but poor in eco- nomic characters, which gives delicate fragrance, but not clean enough. Waiweiba and Mijie Qinggeng neither taste well nor smell sweet, performing ordinary in agro- nomic and economic characters. Hence, the two varieties seem bad in quality and ranks poorly. [Conclusion] In terms of sensory quality, the varieties from high to low were Yunshai No.1, Virginia 934, Cunsanpi, Tengruan No.2, Waiweiba and Mijie Qinggeng.
基金Supported by Project of Guiyang Branch Company,Guizhou Tobacco Company(ZYK[2015]2)~~
文摘Objective] This study was conducted to discuss growth characteristics and partial production and quality characters of different varieties, so as to provide can-didates for tobacco production as wel as a theoretical basis for variety deployment in Guizhou. [Method] ‘K326’ was used as control, the experiment for variance analysis of growth characteristics and partial production and quality characters of dif-ferent tobacco varieties was carried out in Fengsan Town, Kaiyang County, Guizhou Province in 2015. [Result] GY8 grew faster in early stages and slower in late stages, the growth periods of GY2 (130 d) and GY5(129 d) were the longest, while those of Yun85 (121 d) and Yun87 (121 d) were the shortest; and GY2, GY5 and GY8 had larger plant heights, maximum leaf widths and maximum leaf areas, and Yun85, Yun87 and K326 showed larger stem girths and maximum leaf lengths. Yun87 exhibited lower natural incidences of diseases, while Yun85 and GY8 showed higher incidences of diseases. GY2, GY5 and GY8 had higher nicotine, total nitro-gen, K and Cl contents, while Yun85, Yun87 and K326 had higher total sugar and reducing sugar contents and higher total sugar/nicotine ratio. Yun85 and Yun87 showed better economic characters, while GY5 and GY8 showed poorer economic characters. [Conclusion] Yun85 and Yun87 have quality characters better than GY2 and GY8, field natural incidences of diseases lower than GY2 and GY8, and better economic characters, and thus could serve as candidates in future flue-cured tobac-co production in Guizhou.
基金Supported by National Major Projects for the GMO Cultivation of New Varieties in China(2012ZX08013015)
文摘[Objective] Based on the cotton variety high yielding potential, fiber quality traits, disease resistance, and early maturity characters, a cultivar registration index model was developed to simplify the tedious calculation process in national cotton registration procedure, and thus to enhance the practical application of cultivar regis- tration index in cotton breeding ancl cotton recommending. [Method] By means of correlation analysis, partial correlation analysis and path analysis methods, the cor- relation of cotton main properties and their effects on cultivar registration index were explored using the dataset of national cotton regional trials in Yangtze River Valley during 1996-2013. The cultivar registration index model was constructed with step- wise regression statistical technique to ascertain the quantitative relationship of main characters with cultivar registration index, and the regional cotton trial dataset in 2013 was used to validate the model. [Result] Several characters with larger deter- minants to cultivar registration index were screened out,ie. lint yield increase ratio, pro-frost yield ratio, verticillium wilt index, fiber strength, fusarium wilt index and mi- cronaire value. The cultivar registration index model defined the functional relation- ship of cultivar registration index with the selected main characters, among which lint yield increase ratio, fiber strength and micronaire value contributed most to culti- var registration index. The model validation with regional cotton trials in 2013 indi- cated the root mean square error, RMSE was only 2.77, and the variation coeffi- cient was 6.77%, which confirmed the model prediction effect was quite perfect. [Conclusion] The developed cultivar registration index model was reliable enough to simulate the complicated scoring system in cultivar registration procedure, also sim- plified cotton registration process, and enhanced the practicability of the cultivar reg- istration index.
基金The study was supported by Hi-tech Research and Development Project of China (No. 2004AA211142), National Natural Science Foundation of China (No. 30270819). The development of source materials used in the study was supported by the Rockefeller Foundation.
文摘Rice is the staple food for more than half of the world population. The utilization of the wild abortive cytoplasmic male sterility (CMS) in 1970s has significantly raised rice yield potential. But the world's annual rice production will have to increase 70 percent over the next 30 years, to keep up with the demends of the growing population.
基金Supported by the National Natural Science Foundation of China(No.31371615,31071404)
文摘In order to provide the reference of improving the nutritional quality traits in carotenoids and screening its resources of wheat varieties, 185 wheat varieties or lines were selected as materials to test the carotenoids content, lipoxygenase activity, whiteness, yellowness and some other quality traits of whole mill in wheat.The results showed that there were highly significant variations in lipoxygenase activity,carotenoids content, whiteness and yellowness among those sample of wheat varieties; carotenoids content was significantly and positively correlated with yellowness.Cluster analysis was performed based on carotenoids content clustered all the varieties or lines into three major groups. Additionally, carotenoids were discussed in the application of nutritional quality improvement in wheat.
文摘An experiment was conducted on Fluvisols of Awassa for two consecutive years (2005-2006) to determine effects of planting pattern and plant density on dry matter accumulation, nodulation, protein and oil content in early and late maturing soybean varieties. Results indicated that Awassa-95 variety produced significantly higher (P 〈 0.05) number of nodules/plant (NDN), nodule dry matter (NDM) and leaf dry matter (LDM at R2 (mid flowering) stage of soybean growth than that of variety Belessa-95). Similarly, variety Awassa-95 (45%) produced significantly higher protein content than variety Belessa-95 (40%). However, variety Belessa-95 accumulated significantly higher (P 〈 0.01) dry matter in straw, grain and total biomass at R7 (physiological maturity) stage of soybean growth than variety Awassa-95. Similarly, oil content of variety Belessa-95 (18.1%) was significantly (P 〈 0.05) higher than that of variety Awassa-95 (15.9%). Equidistant rows produced significantly higher (P 〈 0.05) NDM than either rectangular or paired rows. Moreover, soybean plants grown in both rectangular and equidistant rows produced significantly higher (P 〈 0.01) straw dry matter than those grown in paired rows; but, grain dry matter/plant (GDM) was significantly higher (P 〈 0.01) paired and rectangular rows compared to equidistant rows. Plant density also affected the per plant GDM production as it was significantly higher (P 〈 0.01) in 20 and 30 plants/m2 than higher plant densities (40 and 50 plants/m2). However, dry matter and yield components had strong negative association with protein content. In fact, strong positive correlation (R 〉 0.600) occurred between grain yield and its components with dry matter components at R2 (stem dry matter (SDM), leaf dry matter (LDM) and stem + nodule + leaf dry matter together known as TDM) and straw dry matter at R7 in both varieties. This study depicted that soybean plants that produce higher dry matter components at R2 would probably produce more straw dry matter, greater grain yield components and higher grain yield dry matter at later stages.
文摘Maize is an important economic crop grown in Nigeria. Its production is dramatically affect by the pink stem borer--Sesamia caIamistis (Hampson, Noctuidae) and sugarcane borer--Eldana saccharina (Walker, Pyralidae) that are endemic in Southeastern Nigeria. In areas of stress, existing genotypes may marginally do well due to their inherent capabilities. Therefore, it is possible to find useful genes in such areas of stress, since such genes have been responsible for the survival of host crops over the years. Evaluation study was conducted for a range of agronomic characteristics and resistance attributes for 209 local maize collections from Southeastern Nigeria along with three improved check varieties. Field trials were conducted at three locations in a total of four environments in 2001. Highly significant genotypic variances as were noted in all the traits, are indicative of the magnitude of variation that exists among the genotypes, thus providing the opportunity of selection for desirable traits. Furthermore, four traits, namely, leaf feeding, ear damage, stalk lodging and yield were used from across the environments to construct a rank summation index (RSI), which was used to rank the entries for resistance to stem borers. This RSI led to the identification of 11 genotypes which represents the best 5% of the 212 genotypes in resistance ability. Genotype AMA TZBR-WC1 (from International Institute of Tropical Agriculture (IITA), Ibadan) had the best overall resistance levels, followed by genotypes SE NG-77 and SE NG-67 (from Umuahia North), SE NG-62 (from Ikwuano), SE NG-148 (from Ukwa West), SE NG-106 (from Bende), SE NG-119 (from Isiala Ngwa), SE NG-33 (from Ikwuano) and SE NG-65 (from Umuahia North).