| Yield stability is the phenomenon that organisms are compatible with environmental performance.The relative stability of yield stability hinders the exchange of germplasm resources and the promotion of varieties in a wider range.Yield stability includes both interregional stability and inter-annual stability.Productivity Stability Breeding is concerned with crop inter-regional and interannual adaptability.Wheat yield stability theory suggests that wheat yield stability depends on the photoperiodic sensitivity or photoperiodic coordination of a particular species.Productivity and stability breeding is achieved through shuttle-breeding,and CIMMYT which stands for the stability of the breeding carried out their work all over the world.The breeders in China also have some excellent varieties of high yield and stable varieties(lines)The breeding of these varieties(lines)mainly in the same ecological zone between different natural geographical conditions of the shuttle breeding,near the ecological area of the shuttle breeding and cross-ecological area shuttle breeding mode.In order to develop the stability of breeding work better,scientists have done a lot of basic theoretical research.The research on yield stability related genes is carried out according to the idea of "top-down" and "bottom-up".There are so many gene have been found which is related to yield stability,such as photoperiod related genes(phd),vernalized gene family(vrn),flowering suppressor gene(flc),CO/FT regulatory elements related to sunshine length,and other genes associated with abiotic stress.In this study,we used the top-down strategy to study the differences of the adaptability phenotypic between different yield,and to determine the appropriate yield stability analysis method,and then use the RIL came from CN17×MY11 to test the phenotypic phenotype and yield in cross-ecological zone,the QTLs,which identified by SSR molecular markers are used to related to the yield stability of cultivars were found,which provided reference for yield stability breeding.The results showed that different cultivars(lines)from different ecological regions showed great different in adaptability in shuttle breeding.AK58 which come from Huanghuai wheat area and MY 11 or R 320 which are southwest wheat varieties maintain high yield stability;BN082 which is the Huanghuai wheat variety and CN 17 which come from southwest wheat area show serious yield fluctuate in cross-ecological area planting.Through the comparative study of the high stability coefficient method and the membership function method,it is considered that both of the high stability coefficient method and subordinate function values analysis are all suitable for determining the yield stability of the cultivars.As the yield stability is a comprehensive index,this paper attempts to investigate the effect of 1R chromosome fragment from Lolium perenne L which is high adaptability than wheat.It was found that IRS did not carry a good gene to improve the stability of wheat The presence of IRS chromosomes did not affect the yield stability of wheat.In order to study the q?antitative traits of yield stability,the recombinant inbred lines(RILs)containing 175 lines were constructed by two parent CN17 ×MY11.And the genetic map of wheat was established by SSR marker of RIL population.The map contained 216 molecular markers,which were evenly distributed on 21 chromosomes with an average distance of 20cM.The response of the RIL population yield related traits to environmental was examined before QTL mapping,and the results show that in addition to the tiller number and grain weight,several other yield related traits,such as plant height,spike length,spikelet number,tillering number,grain yield and the combination of traits such as variance analysis model are reached extremely significant level,which can be explained more than 70%by genotype,environment and genotype × environment,and genotype,environment and genotype × environment show the significant or extremely significant influence of the above traits.Genotype explained greater effect on spike length than environment and genotype x environment,while the environment of variance components in panicle length,spikelet numbers and thousand kernel weight(TKW)is bigger,whichsuggested that there are influenced greatly by the environment.The RIL population yield-related traits analysis showed that each index in the RIL population have considerable variation which beyond the variation amplitude of parents,and It suggested that related traits genetic locus maybe was recombinant extensively and were influenced greatly by the environment.The distribution of most of the yield related traits showed basic normally distributed within the group.The QTLs of wheat yield-related QTLs were mapped into the linkage group,and three QTL hot loci were found on the 5A,2B and 4D chromosomes.A number of QTLs(Q.PY-5A)related to single plant yield and panicle length were also found,and the QTLs.(Q.PN-2B).for the number of tillers and the yield 'per plant were determined in different environments.A plant height QTL(Q.PH-4D)was determined in each environment,and it the QTL locus on chromosome 4D between barc288-wmc720,both sides of the loci spacing were 1.5 cM.It is a negative effects locus,and it can explain 15.2%of the variation rate.It is speculated that it may belong to wheat Rht gene families and near the dwarfing gene(RHt10).It was found that the main effect QTL of plant height is not located in the same linkage group with TKW ones,which suggested that is possible to reduce the plant height and increase the TKW at the same time.High stability coefficient method and subordinate function values analysis were used to examining the yield stability of the RIL population,and two main effect QTL were located.QTL(sQ.IH-5B)which adjacent with a TKW QTL(Q.GW-5B)was detected by both of the two method,QTL(sQ.EH-2A)which linkage with one of the plant yield QTL(Q.PY-2A1)and adjacent with photoperiod gene(Ppd-A1).It is also proved that the use of high stability coefficient method and subordinate function value method for QTL mapping in wheat yield stability is feasible. |
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