Experimental data showed that under moderate soil fertility conditions in Hexi Irrigation area, the best culture pattern was: nitrogen 190.5~204.6 kg/hm~2, P_2O_5 105 kg/hm~2, sowing density 593.4×10~4 seeds/hm~2. With the combination of those factors, the grain yield could reach 7 747.5 (kg/hm~2), (protein) content 15.9%, (protein) yield 1 228.5 kg/hm~2. Under the culture conditions of the (experiment), the SDS-sedimentation volume, gluten swelling volume and water-holding capacity were not correlated to the culture factors. The effect of (nitrogen) on grain yield and quality was most (significant). From the (experiment), it could be found that the base phosphate of irrigation plains was utilized in high level while (nitrogen) was utilized less effectively. It suggested that the rate of phosphate should be stabilized and the utilizing efficiency of (nitrogen) should be improved and the sowing rate sould be lowered.
In order to understand the quality classification of wheat varieties in China, 31 spring wheat and 58 winter wheat varieties were selected to analyze their quality classification and relevant quality types. In the meantime, they were compared with the same quality type of wheat varieties developed in the USA and Canada. The results showed that the mean of quality characters of spring wheat were higher than that of winter wheat, and the proportions of high quality among winter wheat varieties were higher than that of the spring wheat varieties. The strong gluten wheat varieties took up 65. 2% of the total samples, the medium gluten and weak gluten wheat varieties took up 6. 7% and 2. 2% of the total samples, respectively.
In order to study the drought characters in photosynthesis of different ecological type wheat varieties, the photosynthesis characteristic of the different ecological type wheat varieties under drought stress was studied by measuring the chlorophyll fluorescence dynamic parameters. The results indicated that Fm、Fv、Fv/Fm and Fv/Fo values decreased gradually, but Fo values increased under drought stress; The variable range depended on the ecological type.The variation of these chlorophyll fluorescence parameters was closely related to drought tolerance of wheat varieties.It was possible to determine the drought resistance in wheat using chlorophyll fluorescence characters.
A study on pasting property of wheat flour coming from different milling systems, which is (important) to producing different kinds of special used wheat flour was conducted. The pasting properties of 60 flour samples from different milling systems were analyzed and compared. The results indicated that their pasting properties were significantly different. The samples from middling system, sediment system and re-sieve system were lower in pasting temperature, shorter in pasting time, higher in peak viscosity, and medium in protein content. The changes of moisture, protein content, start pasting time and pasting temperature in all samples were smaller, But the differences of peak viscosity, setback and stability among different milling systems or in the system were significant.
In China, at least 5 commercial black kernel wheat cultivars have been developed. However, their chromosomal and protein constitutions, as well as disease responses of these cultivars are less reported. In this paper, chromosomal configuration of black kernel wheat Luozhen 1 was characterized by chromosome C-banding, genomic in situ hybridization analysis. In addition to chromosome 7B differing from that of Chinese Spring, a pair of 1BL/1RS translocation was found in its chromosomal constitution. The mean chromosomal pairing configuration at PMC MⅠ of 1.97 +19.03 showed Luozhen 1 to be cytologically stable. SDS-PAGE analysis revealed that subunits of 1, 7+8 and 5+10 of HMW-Glu existed in Luozhen 1. The specific secalin of rye coded by 1RS GldB3 was also demonstrated, in addition, several polymorphic bands different from Chinese Spring after A-PAGE indicating more allelic variations in Luozhen1. Disease evaluation indicated that Luozhen 1 was highly susceptible to Fusarium head blight and powdery mildew.
196 single half seeds were identified for Wx proteins and meanwhile measured for amylose content in a F_2 segregating population from the cross RAC892(normal type) × TN(waxy type) in bread wheat.Semolina milled from 1 double null allels of Wx-B1 and Wx-D1 and 2 normal bread wheat lines was analysed for amylose content,swelling power and starch pasting properties as measured by the Rapid Viscoanalyzer(RVA).The result showed the amylose content of single Wx protein deficiency was(3.29~)(7.15) percentage points lower than that of the normal type,9.45~13.82 percentage points lower in the double null Wx proteins than that in the normal type and the amylose content for whole proteins deficiencies was almost zero.The amylose content of the double null allels of Wx-B1 and Wx-D1 was 5.62~7.49 percentage points lower than that of the normal type,and swelling power was 4.51~4.72(g/g) higher than that of the normal type.And the double null allels of Wx-B1 and Wx-D1 line had much higher starch peak viscosity than the two normal lines.
SQ-1 is a new kind of chemical hybridizing agent. To study the effect of male sterility induced by SQ-1 and the reaction between different cultivars and SQ-1, the rate of male sterility of 34 cultivars could be from 95% to 100% by spraying SQ-1 on the leaves with the dose of 5. 0 kg/hm2 during the stage of feeks 8. 0 to 9. 0. The results showed that SQ-1 could induce different wheat cultivars to be complete male-sterility. The pistil fertility in the supplementary pollination were normal.
Wheat grain yield and quality were strongly influenced by heat stress during grain filling stage. The effects of high temperature on kernel gluten protein and starch accumulation, and associated molecular mechanisms were reviewed in this paper. High temperature leaded to specific gene expression, which resulted in gluten and starch quality variation. The molecular biology would provide an effective tool to understand the mechanism of quality variation.
In this study, 6 high-quality varieties and 7 high-yield varieties were crossed to get 23 reciprocal F_1 and F_2 populations. Heterosis and parent-offspring correlation in quality characters were analyzed. All hybrids were divided into 3 type of combination, the genetic segregation of HMW-GS and their relationship to quality characters in hybrids were studied. The results showed that there was no apparent difference between F_1 and F_2 populations on quality heterosis. Genotype was the main factor on the quality of hybrid wheats, the combinations of good quality/good quality and good quality/high yield were easy to get better quality hybrids. Significant heterosis in F_1 and F_2 populations showed that heterosis was practicable in improving wheat quality. HMW-GS were inherited based on Mendel's laws of gene independent assortment and free combination. The parents who contained more high-quality subunits would increase the frequency of HMW-GS in F_1 and F_2, which could improve the quality of hybrid wheats.
Some researches on the Agrobacterium-mediated transformation of wheat have been successfully carried out in recent years,but the transformation efficiency is still not good enough.Wheat genotype might be one of the most important factors in improving the transformation efficiency.For such a purpose,c58C1 Agrobacterium strain harboring a binary vector pPTN290 with nptII gene and GUS gene was used to infect different explants of different wheat genotypes which including 31 spring wheat genotypes and 59 winter wheat genotypes and collected from different domestic areas in this research.To evaluate the sensitivity of these genotypes to the Agrobacterium,the infected explants by Agrobacterium were tested by X-Gluc staining for GUS gene transient expression.The result showed that the inflorescences of CA9924,Beinong 49,Xinong 2611,Jingdong 11 were sensitive to the Agrobacterium infection,and GUS gene transient expression frequency was from 66.7% to 82.8%.The immature embryos of 97H2169,Lunxuan208,Lankao 906 and Yangmai 6 were sensitive to the Agrobacterium infection,and GUS gene transient expression frequency ranged from 50.0% to 93.3%.It was indicated that most genotypes were not sensitive to the Agrobacterium,whether to their immature embryos or to their inflorescences.The results also suggested that while the coculture step processed on paper.The GUS gene transient expression frequency on average could be increased 16.6% more than that prosessed on solid medium.
One hundred and twenty-eight wheat cultivars from America were analyzed by SDS-PAGE to determine their high molecular weight(HMW)glutenin subunit combinations.A total of fifteen alleles were identified at Glu-1.Glu-A1 encoded four subunits,1,2~*,Nulland an unidentified subunit,and Null was the major type;Glu-B1 encoded seven subunits,7,7+8,7+9,6+8,13+16,14+15,17+18,and 7+9 was the major type;Glu-D1 encoded four subunits,2+12,5+10,2+10,2+ an unidentified subunit,and 5+10 was the major type.Furthermore,twenty-seven subunit combinations were defected,and the composition of 2~*,7+9,5+10was the major type.Payne scores ranged from 4 to 10,with an average of 7.5.Therefore the quality of these varieties were good.
The net photosynthetic rate(Pn), transpiration rate(Tr), stomatal (conductance)(Gs), (intercellular) CO_2 (concentration), chlorophyll (content) and the (contribution) rate of different (positions) leaf to grain of winter wheat were measured at grain filling stage while relay (intercropped) with cotton, under the (identical) fertility and soil moisture (condition). The (results) showed that the change trend of Pn and Tr were (consistent), and the order was flag leaf (FL), the second leaf (Cd2L), the third leaf (Cd3L) and the fourth (Cd4L) leaf from big to small. Along with the (senescence) (progress) of wheat leaves, the (chlorophyll) (content) descended rapidly. The photosynthesis decline of Cd3L and Cd4L were mainly due to (non-stomatal) (limitation,) FL and Cd2L were mainly due to stomatal (limitation) at prophase, but due to (non-stomatal) (limitation) at anaphase, and the time of (non-stomatal) (limitation) of FL was later (appeared) than that of Cd2L. The (contribution) rate of FL to grain was 18.8%, and that of Cd2L, Cd3L, Cd4L was 14.2%, (5.6%) and (-1.2%), (respectively). The (results) suggested that the attenuation level of (chlorophyll) (content) (directly) influence the time of (non-stomatal) (limitation) rather than the trend and (values). The (consuming) of earlier (senescent) leaves at lower (positions) is more than accumulation, therefore the (contribution) rate to the grain filling is in a negative (effect).
Galanthus nivlis agglutinin (GNA) gene, which was synthesized in laboratory according to the sequence published, was transferred into the immature embryo callus of Zhengzhou 9405, a common wheat variety with high quality, by particle ballistic. After several time selection on the medium, one bialaphos resistant plantlet was regenerated from 360 bombarded calli,referred as G Zhengzhou 9405. The offspring of the T_1 generation and T_2 generation were tested for DNA integration by PCR, Southern blot, and aphid resistance by manual inoculation. The results indicated that GNA gene had inserted onto the genome of Zhengzhou 9405, and the transgenic wheat showed good resistance to aphids in field. Till now, homozygous transgenic lines stably in genetics have been developed, and environmental release experiment is being carried out.
This study was to facilitate the effective use of Yr2 gene and Yr2 gene cloning based on tight linkage. Using near isogenic line Taichung 29 * 6/Heines Ⅶ and Susceptible parent Taichung 29, we established F2 segregation population and identified its stripe rust resistance in seeding stage. Genetic analysis suggested that the stripe rust resistance Taichung 29 * 6/Heines Ⅶ was controlled by a single gene. By SSR analysis with 45 pairs of primers located on 7B chromesome in 171 individuals of F2 segregation population and their resistant and susceptible parents, we screened a molecular marker WMC364-207bp/201bp that linked to the stripe rust resistance gene Yr2. Genetic distance among marker WMC364-207bp/201bp and resistance gene Yr2 was calculated as 5. 6 cM.
In order to explore the most suitable method for rescuing wheat × Leymus angustus immature embryos, two ways of young embryo rescue,embryo culture and embryo-callus culture, was compared on their effects. The result showed that 27.9% embryos germinated when rescued with embryo culture; While only 18.6% embryos developed to intact plants, some embryos stopped developing after germinated, or only coleoptile developed, or radicle and coleoptile developed, but plantule didn't develop; some developed into abnormal plants. 123 regenerated hybrid plants (41 plants/clone) were recovered by embryo-callus culture. But as to which way to be taken, research purpose should be considered. The two ways of embryo rescue were discussed on their advantages and disadvantages and principle of their application.
In order to elucidate the role of low doses of γ ray in enhancing alien genetic transfer,common wheat CV Chinese Spring and J-11 as female parents and rye CV AR202 as male parent were used to study the effect of pollen irradiation by γ ray on embryo and endosperm development.Irradiation doses were 5,9,15,30,50 and 100 Gy.Seed setting(%)、percentage of seeds with embryos、rate of seedling were estimated for different treatments.The results showed that low doses of γ irradiation(5~9 Gy) enhanced slightly the seed setting,1.3%~2.4% higher than the control of(J-11/AR202).When doses were higher than 15 Gy,seed setting percentage decreased gradually,ranged from 83.8%~63.9%.Irradiation with any doses was harmful to embryo and endosperm development,and the rate of seed with embryo,rate of seedlings to pollinated florets decreased with the increased doses.For the combination of(J-11/AR202),percentage of seed with embryos in the control was 100%;96.5%~69.7% in 5~100 Gy;Seedling rate in the control was 93.3%,90.0%~24.6% in 5~100 Gy treatments.Percentage of seeds with abnormal embryos increased significantly with the doses.5.9%～8.8% of badly developed embryos recovered after pollination with 50~100 Gy γ irradiation developed to seedling that was difficult to obtained using the conventional way.So more mutants could be recovered with a pollen irradiation technique combined with embryo rescue.
Reactive oxygen species (ROS) can stimulate seed germination, but the mechanism is not clear. In this study, the effect of ROS on α-amylase expression of germinating wheat embryo treated with ABA and water stress was studied by IEF technology. The results showed that during seed germination,ABA and water stress can inhibit α-amylase expression of embryo and growth of radicles,the inhibition of water stress but not ABA is suppressed by ROS. Therefore,ROS is favorable to seed germination under conditions of water stress.
In order to study the heterosis of two parents in hybrid wheat breeding,the genetic distance of 18 core parents which were used in hybrid breeding practice was analyzed by Ramdom Amplified Polymorphism DNA(RAPD),their heterosis over Mid-parent,high parent and special combining ability of 81 combinations which derived from the 18 core parents were tested in field.The results showed that the polymorphisms were low between core hybrid wheat parents.15 primers of 80 were found to amplify polymorphic products.Based on polymorphic products of 15 primers,heterosis groups of hybrid wheat could be established.No significant positive correlation was found between RAPD genetic distance and yield heterosis of hybrid wheat.At the heterosis over high parent,the number of kernel on one head in hybrid wheat was lower than its male parents,even there was the biggest RAPD genetic distance between male and female parents.No significant positive correlation was found between RAPD genetic distance and special combining ability. It was considered that RAPD genetic distance might be difficult to predict heterosis of hybrid wheat.
Pre-harvest sprouting (PHS)is one of the most damaging diseases in rain-affected wheat (Triticum aestivum L.) crops. Sprouting resistant mechanism in cereal grains has focused on the regulation of (germination) by phytohormone abscisic acid, (especially) (embryonic) sensitivity to ABA. Comprehension on (embryonic) sensitivity to ABA will help to understand the resistant mechanism of cultivars. Using different sprouting resistant genotypes,we studied the (embryonic) sensitivity to ABA during seed (development) as well as mature seed (germination) ability. The results are as follows: During seed (development), the (embryonic) (germination) ability and sensitivity to ABA are varied among genotypes. The descendent values of (germination) index from 25 d to 35 d in sprouting resistant genotype are higher than in sprouting (susceptible) genotype. Therefore, the (embryo) dormancy is acquired in late stage of seed (development). In mature seed, the increased values of (germination) index of (embryo) in red coat grain cultivars, (especially) genotype (susceptible) to PHS, are higher than in white seed. The higher (germination) ability of (mature) (embryo) is,the (shorter) seed dormancy stage is.
This review provides a historical overview on fundamental process of (isolated) microspore culture of Triticeae crops, including growth and harvest of donor plants, pretreatment of microspore culture, (isolation) and purification methods, factors influencing (embryogenesis) and regeneration of (embryoid). A (current) (understanding) of the cellular, molecular and biochemical events associated with microspore (embryogenesis) is also presented. Under most circumstance, physical, physiological and/or chemical stress treatments need to be employed to trigger androgenesis, so that switch microspore from gametophytic (development) to a sporophytic pathway. Isolated microspore culture and studies of cellular, molecular and biochemical mechanisms related to microspore (embryogenesis) have yielded useful information for both (understanding) androgenesis and improving the efficiency of doubled haploid production. A great deal of progress has been made thus far in the (understanding) of (embryogenesis) at the cellular level, meanwhile, a few (embryoid-specific) genes temporally expressed during microspore (embryogenesis) have been identified in wheat, however, the precise mechanisms for microspore (embryogenesis) need a further research.
