Genetic Analysis For Quality Trait And Resistance To Yellow Rust In Wheat RILs Of 'Chuanmai 42'×'Chuannong 16'

After the cross between 'Chuannongl6' of high yield and good quality trait,and 'Chuanmai42',a highly yielding and resistant variety to yellow rust derived from Synthetic hexaploid wheat,127 recombinant inbred lines(RILs) were obtained.Using these RILs, the QTLs controlled the quality traits were detected,and the gene resistance to yellow rust was analyzed..The main results were described as following:1.The performances of 13 protein and starch characters and 7 agronomic characters were detected,and the majority of these characters had the normal distributions in this RILs population.Except for the water absorption,the protein content,grain hardness,dry glutenin content,wet glutenin content,glutenin indexes,sedimentation value,development time,stability time,time to breakdown,mixing tolerance index,farinograph quality number and falling number were significantly related to each other.The majority of the 13 quality characters were significantly negatively related to the 7 agronomic characters.The distribution of late maturity a-amylase(LMA) in RILs was 1:1,which was in accordance to the segregation rate of one pair allele.2.Forty-four QTLs were obtained after the analysis of 13 protein and starch characters in 127 RILs and their parents 'Chuannong 16' and 'Chuanmai42',the these QTLs were allocated to 9 chromosomes:1A,1B,2D,3D,4A,4D,5A,5Band 7D.A single QTL could explain 4.48%-66.15%of the phenotype variation.Twenty-six QTLs,mainly related to characters of protein,stability time,development time,mixing tolerance index, falling number and sedimentation value,were derived from 'Chuanmai42',among which 16 QTLs were found to be have positive addictive effects.Eighteen QTLs,mainly related to dry glutenin content,wet glutenin content,farinograph quality number and time to breakdown,were derived from 'Chuannong16',among which 9 QTLs had positive addictive effects.3.The results of SDS-PAGE and A-PAGE electrophoresis indicated that the parents ofRILs,'Chuannongl6' and 'Chuanmai42',had the subunit combinations of 1,6+8,2+12 and 1,20,5 + 10,respectively.No mutant subunit was detected in RILs population.In the RILs,four subunit combinations were(1,6+8,2+12),(1,20,5+10),(1,6+8,5+10) and (1,20,2+12),among which the frequency of the combination(1,6+8,5+10) were the highest.Compared to subunit 2+12,the subunit 5+10 had to the positive effects on sedimentation value,glutenin index and development time,while had the negative effects on value of glutenin,wet glutenin content and mixing tolerance index.Compared to subunit 20,subunit 6+8 resulted in the larger index of glutenin.The effects of different subunit combination on the quality characters followed the order of(1,6+8,5+10)＞(1,20, 5+10)＞(1,6+8,2+12)＞(1,20,2+12).4.The 127 RILs were rich in the genetic polymorphism of gliadin.A total of 39 gliadin bands and 113 band combinations were detected.The number of protein bands in each RILs varied from 14 to 25.The frequency of each band in 127 RILs varied from 0.78%to 100%.The pattern of gliadin bands were 18,10,4 and 7 in the four zones of co,γ,β,andα,respectively.There were 4 common bands.Eight new bands were detected, among which 7 and 1 were observed in co zone andγzone,respectively.The cluster analysis indicated that two distinctive clusters were separated at the analogue index of 0.61, among which 26 RILs and 'Chuannong16' were clustered into in groupâ… ,while 101 RILs and 'Chuanmai42' were clustered into groupâ…¡.5.The effects of 1BL/1RS translocation chromosome on quality and agronomic characters detected in RILs derived from the cross between 'Chuanmai42' and 'Chuannong 16'.The presence of 1BL/1RS translocation chromosome had the significant effectes on days from emergence to heading,tillers per plant,spikes per plant and spikelet numbers per spike,but its effects on the majority of the quality characters were not significant.The 1BL/1RS translocation chromosome could lead to lower sedimentation value and higher mixing tolerance index,and consequently the poorer wheat quality.Forty loci specific to synthetic hexaploid wheat were detected in RILs,among which 18 loci were significantly correlated to quality characters. 6.The genes resistance to yellow rust in 'Chuanmai42' were studied in the F₁,F₂ and BC₁ populations of the crosses of 'Chuanmai42' to susceptible varieties 'Mianyang26' and 'Mianyang335'.The segregation ratios of resistant and susceptible plants after the inoculation of race CY32 of Puccinia striiformis f.sp.tritici indicated that the resistance was controlled by one dominant gene,temporally named as YrCH42.The further analyses indicated that YrCH42 was located at the same locus of Yr24 and Yr26,and no virulent isolates of P.striiformis f.sp.tritici has been found.