化学杂交剂GENESIS诱导小麦雄性不育的细胞形态学观察

在小麦幼穗发育期的药隔期至四分体期 ,用 5 .0 kg/ hm2剂量的 GENESIS进行处理 ,结果表明 ,GENESIS可诱导小麦产生 10 0 %的雄性不育率 ,且不育株率超过 99%以上 ,具有良好的诱导雄性不育的效果 .小麦经 GENE-SIS处理后 ,小孢子发育出现异常 ,败育型小孢子有单核花粉、二核花粉和不正常的三核花粉 ,同时还发现有四核和五核花粉以及在花粉发育过程中原生质体解体 ,仅留下花粉壁的空壳花粉 .不育花药不开裂 ,花粉囊除了表皮及纤维层外 ,还可观察到延迟解体的绒毡层 。

Assessment of Genetic Diversity of Yunnan,Tibetan,and Xinjiang Wheat Using SSR Markers

A total of 206 SSR （Simple Sequence Repeats） primer pairs were used to detect genetic diversity in 52 accessions of three unique wheat varieties of western China. A total of 488, 472, and 308 allelic variants were detected in 31 Yunnan, 15 Tibetan and 6 Xinjiang wheat accessions with an average of PIC values 0.2764, 0.3082, and 0.1944, respectively. Substantial differences in allelic polymorphisms were detected by SSR markers in all the 21 chromosomes, the 7 homoeologous groups, and the three genomes （A, B, and D） in Yunnan, Tibetan, and Xinjiang wheat. The highest and lowest allelic polymorphisms in all the 21 chromosomes were observed in 3B and 1D chromosomes, respectively. The lowest and highest allelic polymorphisms among the seven homoeologous groups was observed in 6 and 3 homoeologous groups, respectively. Among the three genomes, B genome showed the highest, A the intermediate, and D the lowest allelic polymorphism. The genetic distance （GD） indexes within Yunnan, Tibetan, and Xinjiang wheat, and between different wheat types were calculated. The GD value was found to be much higher within Yunnan and Tibetan wheat than within Xinjiang wheat, but the GD value between Yunnan and Tibetan wheat was lower than those between Yunnan and Xinjiang wheat, and between Tibetan and Xinjiang wheat. The cluster analysis indicated a closer relationship between Yunnan and Tibetan wheat than that between Yunnan and Xinjiang wheat or between Tibetan and Xinjiang wheat.

Structural Characteristics of Thicker-culms in the High-yield Wheat Cultivars

The culm of the Triticum aestivum L. cv. “Lankao 906_4”, a high_yield cultivar, in comparison with “Jing 411”, a widely_planted cultivar, was studied by means of anatomical technique coupled with mechanical and chemical theory. A anatomical analysis revealed that “Lankao 906_4” possessed thicker mechanical tissue and larger vascular bundle area than those of “Jing 411”. In terms of the resistance to lodging, “Lankao 906_4” had higher culm strength. Furthermore the content of lignin was semiquantitatively analyzed with confocal laser scanning mircoscope (CLSM), and revealed a much higher lignin content in the culm of “Lankao 906_4” than that in the culm of “Jing 411”. All of these indicated that the characteristics of culm were important factors in breeding the super_production wheat cultivar.

A Unique Aegilops tauschii Genotype Needless to Immature Embryo Culture in Cross with Wheat

Common or bread wheat ( Triticum aestivum L., AABBDD, 2n=42) originated ca. 8 000 years ago from hybridization of tetraploid wheat ( Triticum turgidum L., AABB, 2n=28) and diploid Aegilops tauschii Coss. (DD, 2n=14). An essential prerequisite for this evolutionary step is that the natural hybrids between tetraploid wheat and diploid Aegilops tauschii can produce relatively many filled seeds which germinated well. In this study, without special techniques, e.g. immature embryo culture, out of 22 Ae. tauschii accessions, the genotype AS60 produced relatively many filled seeds which germinated well. The seed germination percentages in the crosses of Ae. tauschii ×tetraploid wheat, tetraploid wheat× Ae. tauschii and Ae. tauschii ×common wheat were, respectively, 50.0%, 57.1% and 45.5%. It seems that Ae. tauschii accession AS60 has a unique genotype which facilitate hybrid seed development and viability, and which meets with the prerequisite for wheat evolutionary. Furthermore, the significance of this finding for common wheat improvement and evolution was discussed.

Changes in Levels of Endogenous Plant Hormones During Floret Development in Wheat Genotypes of Different Spike Sizes

The levels of endogenous plant hormones regulate floret development and degeneration, and thus grain set in flower crops. This study was undertaken to characterize the changes of endogenous hormone levels during floret development in three wheat ( Triticum aestivum L.) genotypes: “97J1' with the highest grain set and fertile florets per spike, “H8679' with the lowest grain set and fertile florets per spike, and a medium, “YM158'. The results showed that the peak level of ABA appeared between stamen and pistil differentiation and antherlobe formation of floret development, and the timing delayed with the size of spike (earliest in “H8679” and latest in “97J1”). From antherlobe formation to meiosis, the levels of ABA and GA 1+3 decreased sharply in the ears of “97J1”, while in the ears of “H8679” there was only a slight decrease in ABA, and even an increase in GA 1+3 . The ratio of isopentenyladenosine (iPA)/ABA and IAA/ABA in the ears of “97J1” increased sharply from antherlobe formation to meiosis, but changed only slightly in the ears of “H8679”. At antherlobe formation, IAA and GA 1+3 levels were higher in the ears of “97J1”, but lower in the ears of “H8679” than in the leaves. At meiosis, ABA, GA 1+3 and IAA levels in the “97J1” ears were much lower than in the leaves, but similar in “H8679”. These results indicated that the sharp decreases of ABA and GA 1+3 in ears from antherlobe formation to meiosis and the lowest maintenance at meiosis may be favorable for development of fertile florets and enhancement of grain set in wheat.

Dynamic Changes of Nitrate Reductase Activity within 24 Hours

[Objective] The research aimed to study the circadian rhythm of nitrate re- ductase activity （NRA） in plant. [Method] The wheat plants at heading stage were used as the materials for the measurement of dynamic changes of nitrate reductase activity （NRA） within 24 h under the conditions of constant high temperature. [Resulti The fluctuation of NRA in wheat changed greatly from 20：00 pm to 11：00 am. The enzyme activity remained constant, but at 14：00 the enzyme activity was the high- est, higher than all the other time points except the enzyme activity measured at11：00. The enzyme activity was the lowest of 17：00, which was lower than all the other time points except the enzyme activity measured at 2：00. [Conclusion] There were autonomous rhythm changes of NRA in wheat in a certain degree.

Research Advances in New Race Ug99 of Puccinia graminis f.sp. tritici

This paper reviewed the research advances of Ug99 and its resistance breeding from the aspects of its discovery, race variation, pathogenicity, distribution, spread, exploration of relative resistant genes, linked molecular marker selection and resistance breeding strategies, to provide basis for comprehensive understanding of the new Puccinia graminis f. sp. tritici race Ug99 and its potential threat to wheat production. Ug99 is a new Puccinia grarninis f. sp. tritici race with high variability, strong pathogenicity and rapid spread speed, which is likely to cause global damages to world wheat production. We should strengthen the exploration and utilization of new resistance genes in wheat and relative species and breeding of new wheat varieties with durable resistance, to control and prevent damages caused by Ug99 and its variants.

Allelopathic Effects of Aqueous Extracts of Different Tissues and Rhizosphere Root of Adzuki Bean on Growth of Wheat Seedlings

Seedlings of wheat were used as receptor plants to study the allelopathic effects of Adzuki Bean aqueous extracts from different organs and rhizosphere soil at different concentrations （0, 10, 40 and 160 g/L） using sand culture of pot method. The results indicated that root aqueous extract of adzuki bean presented promotion effects at low concentrations and inhibition effects at the high concentra- tion on the growth of height and young leaf length of wheat seedlings, but inhibition effects at low concentrations and promotion effects at the high concentration on the growth of root length, the number of lateral roots and dry weigh of underground part of wheat seedlings. With the concentrations of rhizosphere soil, root, stem and leaf aqueous extracts of adzuki bean increasing, their inhibitory allelopathic effects on the growth of height and young leaf of wheat seedlings increased; the physiological parameters of wheat seedlings studied at the low concentrations of aqueous extracts, indicated that root and rhizosphere soil aqueous extracts of adzuki bean improved the activities of hyperoxid dismutase （SOD） and peroxide enzyme（POD）, but reduced the contents of chlorophyll and malonaldehyde （MDA）; the physiological parameters of wheat seedlings studied at the high concentration of aqueous extracts indicated that the leaf aqueous extract of adzuki bean inhibited root vigor, and reduced the contents of Chlorophyll and MDA, but it was found that the aqueous extract significantly improved the activities of SOD and POD; and as to the synthetic allelopathic effect （SE）, the allelopathic effects of different tissues and rhizosphere soil of adzuki bean on wheat seedlings were in order of leaf〉stem〉soil〉root.

A Preliminary Study on Allelopathy of Pogonatum inflexum Aqueous Extract

[Objective] The aim was to study the effects of Pogonatum inflexum aqueous extract on wheat seed germination and seedling growth to cladfy the possible allelopathic effects. [Method] With distilled water as control, wheat seeds were cultivated with the aqueous extract of P. inflexum gametophytes. After 7 days, the germination rate, root length, bud length, biomass and vigor index were determined. [Result] Middle and low concentration of P. inflexum aqueous extract significantly promoted the seed germination and seedling growth of wheat （P〈0.05）. With the in- creased concentration of the aqueous extract, the indexes all increased first and then decreased. The effect intensity of P. inflexum aqueous extract on root growth and biomass of wheat was stronger than that on bud growth. [Conclusion] Low-concentration P. inflexum aqueous extract promoted, while high-concentration Po inflexum aqueous extract inhibited the seed germination and seedling growth wheat.P, inflexum has a certain allelopathic potential, but the specific mechanism needs to be revealed and clarified by further research.

Effect of Postponing Nitrogen Application on Growth and Yield of Different Wheat Cultivars

[Objective] The aim was to study whether there are differences in top- dressing period for wheat cultivars. [Method] With three representative wheat culti- vats selected, effects of different N topdressing period on wheat tiller dynamics and yield components were studied. [Result] Appropriately postponing N topdressing time improved the yield of wheat. Appropriate N topdressing time tended to be volatile upon wheat cultivar. Jointing stage was appropriate for topdresSing for most wheat cultivars such as Jimai 22 and Linmai No. 4 and flowering stage was appropriate for the cultivar featured by early-senescence such as LN66. [Conclusion]It is neces- sary to select the optimal topdressing time according to wheat characteristics.

Effects of Waterlogging in Different Growth Stages on the Photosynthesis,Growth,Yield,and Protein Content of Three Wheat Cultivars in Jianghan Plain

To maintain high wheat grain yield in areas where frequent and periodic waterlogging occurs,the effects of waterlogging on the photosynthesis,growth,yield,and protein content of three wheat cultivars,namely Xiangmai55(X55),Jingmai102(J102),and Zhengmai9023(Z9023),in four different growth stages were investigated.Experiments were conducted in specially designed experimental tanks in the middle and lower reaches of the Yangtze River during the 2012-2013 and 2013-2014 wheat growing seasons in China.Results showed that X55 was the most susceptible to waterlogging,followed by J102 and Z9023.Chlorophyll content reduction and leaf senescence,which resulted in decreased green-to-total leaf number ratio,were induced to the greatest extents by waterlogging in booting and flowering stages,followed by milky stage.Meanwhile,chlorophyll content in flag leaf,plant height were significantly decreased by waterlogging in jointing stage but effectively recovered after waterlogging withdrawal,and recovery ability varied among the cultivars.Plant biomass and grain yield were most significantly decreased by waterlogging in booting and flowering stages,followed by milky and jointing stages.Grain protein content was also considerably affected by waterlogging depending on growth stage and cultivars.The decreased grain yield caused by waterlogging was mostly due to the sharp decline in 1 000-grain mass.Waterlogging led to reduced protein yield in all growth stages in three wheat cultivars.Above all,in this experiment,waterlogging decreased grain yield significantly,and waterlogging at booting stage and flowering stage was most serious.Comparing the three cultivars,X55 was most sensitive to waterlogging.

Composition of Wheat Rhizosphere Antagonistic Bacteria and Wheat Sharp Eyespot as Affected by Rice Straw Mulching

To assess the effect of rice straw mulching on changes of antagonistic bacteria and the incidence of wheat sharp eyespot, a multi-year field study was performed to compare unmulched plots and the plots mulched with rice straw for two or three years. Bacterial and fungal populations were evaluated in the cultures prepared from the wheat rhizosphere and bulk soils. Rice straw mulching increased the number of pseudomonas colony forming units in wheat rhizosphere and bulk soils. The proportion of total bacteria that were fluorescent pseudomonads was higher in mulched than in unmulched soil. Bacterial isolates antagonistic to Rhizoctonia cerealis were identified using an inhibition zone test. A series of these isolates were typed by partial sequencing of the 16S rRNA gene. Pseudomonads had higher antagonistic activity against R. cerealis than other species, and more than 80% of rhizosphere fluorescent pseudomonads were antagonistic to R. eerealis. The disease indices were lower in the mulched plots than in the unmulched control. These results suggest that rice straw mulching in a rice-wheat rotation increases the number of fluorescent pseudomonads. Additionally, these fluorescent pseudomonads may contribute to the control of wheat sharp eyespot.

Allelopathic Effect of Adzuki Bean Root Aqueous Extracts on Four Crops

For choosing suitable summer-planting adzuki bean crop, this experiment adopted the method of indoor petri dish bioassay to study the allelopathy effect of adzuki bean, radish, cabbage and wheat under different concentrations of adzuki bean root aqueous extracts. The result showed that the adzuki bean had a strong inhibition towards its germination rate and germination index. With the increasing concentration of the adzuki bean root aqueous extract, the seed germination rate and germination index of the three kinds of receptor crops presented a decreasing trend. From the root length, spire length, the number of lateral roots, plant height, fresh mass and other morphological indexes of seedlings, it was concluded that with the increase of concentration of adzuki bean root aqueous extract, only wheat pre- sented a promotion effect while the other two kinds of receptor crops showed an inhibition effect, which were not significant at low concentrations. With the increase of concentration of adzuki bean root extracts, the SOD and POD activities of radish and wheat also increased, while the two kinds of enzyme activities of cabbage showed a decreasing trend. The MDA contents in seedlings of radish and wheat decreased, while the MDA content in cabbage increased significantly, which showed that wheat could be used as a rotation crop of adzuki bean, and radish also had a great application potential in adzuki bean crop rotation.

Agronomic Behavior of a New Cereal （Primary 6x Tritipyrum： AABBEbEb） in Comparison with Modern Triticale and Iranian Bread Wheat Cultivars

The novel salt-tolerant cereal, primary Tritipyrnm, is the third artificially synthesized crop plant. The agronomic traits and grain yields of 13 primary 6x Tritipyrum lines were evaluated and compared with five modern 6x triticale lines and nine bread wheat cultivars at Bahonar University, Kerman, Iran in a completely randomized block design with three replications. The primary Tritipyrum lines increased the grain yield per plant by 2.8% and 14.1% compared to triticale promising lines and Iranian bread wheat cultivars, respectively. Although the primary Tritipyrum lines were late maturing, they were shorter than the triticale lines and wheat cultivars and superior in many characters such as penultimate leaf area, flag leaf length, penultimate leaf length and time to milky ripeness. Genotypes were divided into four groups for agronomic and morphological traits and four groups for grain yield by cluster analyses. All clusters showed significant differences （a = 5%） for all traits and the first cluster, which comprised primary Tritipyrum lines, had a higher mean grain yield than the other clusters. The results of this first large-scale trial indicated the high adaptation of primary Tritipyrum lines to conditions in Kerman province in South-east of Iran.

Assessment of Variabilities in Wheat Genotypes to Yellow and or Strip Rust, Puccinia striiformis in Glass House Conditions

Yellow/stripe rust caused by Puccinia striiformis is a major problem in the Middle East specially Iran. Virulence survey of cereal rust fungi have traditionally used differential host genotype and virulent physiologic race 134 E 134 AT was received to evaluate the segregating lines. A set of 35 segregating lines and three additional susceptible cultivars were added, making a total of 38 eultivars-lines. Spreader plants served as a source of inoculums. The plants were evaluated after two months based on infection percentage and the disease scoring scales. The results indicated that, there are significant changes in susceptibility assessments of the segregating lines in contrast to cultivated varieties to the yellow rust P. striiformis as far as the disease incidence and rust development is concerned in these experiments. The selected differential genotypes associated with various levels of resistance. The infection percentages were varied on the lines and the varieties, whereas the severity percentages were entirely different. The lowest severity is of line 38 with 34.70% and the highest in line 1 with 93.49% indicating 2.7 folds reduction in severity. For discrimination among the lines, the results on scoring scales gave distinctions of five classes of resistance, in which, the highest score is 29.93 and the lowest one 11.46. The cluster analysis showed almost similar results and confirmed, the analysis by Duncan＇s Multiple-lest rang as the above five distinctive groups.

Characterization of New Allelic Variation for Glutenin in EMS-Mutant Durum Wheat Population （Triticum turgidum L. subsp, durum （Desf.））

The High Molecular Weight HMW-GS and Low-Molecular-Weight LMW-GS Glutenin Subunits are major determinants of wheat dough processing qualities. Tilling populations was generated by EMS mutagenesis from Chaml durum variety. Protein quality was investigated by SDS sedimentation, protein content, gluten content and thousand kernel weights. 21 mutants were selected from 1,500 lines of tilling population depending on the variations of their electrophoresis profiles. The analysis of Glu-B 1 HMW-GS has showed two types of profiles： lines deficient on Bx7 and lines with expression of new protein between （Bx7-ByS） allelic pair combination. The majority of these mutant lines have showed quality compounds associated with bad technological characteristics like the parent Cham l with the exception of two mutant lines expressing new protein that have significantly stronger gluten properties an one mutant deficient on Bx7 HMW-GS that developed high value of SDS. For Glu-B3 LMW-GS coding for LMW glutenin type 1 and 2, new mutant line showing expression of new protein pattern. The mutant showing over-expression of bands on gel SDS-PAGE for LMW typel like Chaml, have produced the highest protein and gluten content, while the new mutant showing new profile have showed high value of Gluten and SDS.

The Study of the Anatomical Features of Wheat Grains in the Species T. dicoccum Schuebl,, Sort Mironovskaya-808 and AIIoplasmatic Lines （Their Interspecific Hybrids F9）

In cross sections by microscopic studies have examined the features of the shell thickness grains, cells, aleuronic layer and endosperm in the species T. dicoccum Schuebl., sorts Mironovskaya-808 and their interspecific hybrids F9 （alloplasmatic lines）. The result of studies showed the specific and varietal differences, and differences in hybrid plants on linear parameters size grains, the degree of specificity of the shells grains of wheat and identified species and varietal differences as well as differences among hybrids in the linear dimensions of the cells of the aleuronic layer. It is shown that among the studied forms of wheat allocated species T. dicoccum Shuebl. and the lines D-N-05, D-F-05 and D-40-05-KhNA with relatively large grains, a well-developed endosperm, most of thin shells and large grain aleurone layer cells. They are of most interest for further breeding research in terms of nutritional value.

Building a Resilient Wheat Seed System to Resist Rust Risks in Ethiopia

This study is a review of existing reports and summary of some field experiences aiming at building of a resilient wheat seed system to resist rust risks in Ethiopia. Practical gaps in the wheat seed system were identified with regard to understanding of seed system factors that build, or undermine resilience to rust risks. The study has recognized that the formal seed multiplication schemes are too slow to respond to the ever increasing frequencies of wheat rust outbreaks. Therefore, it is indicated that new approaches such as pre-release and farmer based seed multiplication schemes are helpful in insuring availability of seed of rust resistant wheat varieties to the small farmers.

Typology of the Main Fungal Diseases Affecting Winter Wheat in the Grand Duchy of Luxembourg

Over the 2003-2009 period, field campaigns were carried out in order to identify the main fungal diseases of winter wheat （Triticum aestivum） in the Grand-Duchy of Luxembourg. Four fungal diseases （septoria leaf blotch （SLB）, wheat leaf rust （WLR）, wheat powdery mildew （WPM） and fusarium head blight （FHB）） were observed and a regional-based typology was established according to their severity and prevalence. In the Gutland （South）, SLB severity was strong （about 51% on average） and higher than the severity （about 16%） prevailing in the Oesling （North）. Similar typology was observed with the WLR： high severity in the Gutland （66% and 57% for the years 2003 and 2007, respectively） and low severity （〈 1%） in the Oesling. The FHB was also present in the Eastern part of the Gutland, with a prevalence and severity significantly higher （P = 0.049 and P = 0.012, respectively, Tukey＇s test） compared with their values in the Oesling. On the other hand, the WPM severity was high in the Oesling （15% to 40%） while less than 1% in the Gutland. Such a study is important for the spatial mapping of wheat fungal diseases risk based on agroclimatic parameters and for defining optimal frequencies and dates of chemical treatments.

Comparative Analysis of Energy Efficiency in Wheat Production in Different Climate Conditions of Europe

This paper presents results concerning energy efficiency of wheat production considered in the context of specific energy input variation in different climatic conditions of Europe as well as case studies on implementation of selected energy saving measures in practice. The source data collected from the six european union （EU） countries represent five agricultural regions of continental Europe and three climates： continental, temperate and Mediterranean. The life cycle assessment （LCA） methodology was applied to analyze the data excluding of pre-farm gate activities. The total primary energy consumption was decomposed into main energy input streams and it was regressed to yield. In order to compare energy efficiency of wheat production across the geographical areas, the data envelopment analysis （DEA） was applied. It was shown that the highest wheat yield （6.7 t/ha to 8.7 t/ha） at the lowest specific energy input （2.08 GJ/t to 2.56 G J/t） is unique for temperate climate conditions. The yield in continental and Mediterranean climatic conditions is on average lower by 1.3 t/ha and 2.7 t/ha and energy efficiency lower by 14% and 38%, respectively. The case studies have shown that the energy saving activities in wheat production may be universal for the climatic zones or specific for a given geographical location. It was stated that trade-offs between energy, economic, and environmental effects, which are associated with implementation of a given energy saving measure or a set of measures to a great extent depend on the current energy efficiency status of the farm and opportunity for investment, which varies substantially across Europe.