Heterosis Analysis And QTL Mapping For Individual Traits In Barley(Hordeum Vulgare L.)

Barley is planted worldwide with extensive utilization as the important raw material for feed and malting industry as well as Tibetans' principal food.As the rapid development of China's economy,human demand for meat,milk,eggs and beer increases.Therefore,the demand for barley used as raw materials is increasing.Barley is a diploid crop with strong heterosis,the research of barley heterosis can lay a foundation for improving the yield of barley and promoting the stable development of barley industry in China.In this study,113 double haploid(DH)lines derived from a cross(Naso Nijo ×TX9425)were used to construct an "immortalized F2"(IF2)population.Three plant height related traits-plant height(PH),spike length(SL)and internode length below spike(SIL)together with five yield related traits-spike per plant(SP),kernel per spike(KS),thousand kernel weight(TKW),kernel weight per plant(KWP)and dry weight per plant(DWP)were measured in four environments,and heterosis and stability of each trait were analyzed.According to the genotype information developed by genotyping-by-sequencing(GBS)of DH lines and parents,the genotypes of each F1 hybrid were calculated.And then the genetic linkage map was constructed.QTL mapping was performed based on the heterosis of F1 generations.The main results are as follows:1.The heterosis of eight different traits exhibited differently.The occurrence rate of mid parent heterosis were higher in PH,SL,SIL and TKW than in SP,KS,KWP and DWP.Mid-parent heterosis was more common,while better-parent heterosis was less in barley.2.The performance of barley heterosis was significantly influenced by not only genetic factors but also by environment factors and the interaction between the genotype and environment.The stability analysis showed that the stability was different in diverse traits and combinations:PH,SL,SIL and TKW were more stable than SP,KS,KWP and DWP in barley.3.In IF2 population,8 characters and their heterosis showed continuous variation with large coefficient of variation and variation range.The genotypes were significant or extremely significant differences among F1 generation,indicating that the genetic information of the population was rich.4.For 3 plant height related traits,a total of 13 mid-parent heterosis QTL were detected in 4 environments,among these,1 QTL for PH and 2 QTL for SL were identified in 2 environments,and 1 QTL for SIL was identified in 3 environments.For 5 yield related traits,a total of 13 mid-parent QTL were detected,while all of the 13 QTL were only identified in 1 environment.A total of 16 plant height related better-parent QTL were detected,3 QTL for SIL were identified in 2 environments,and 1 QTL for PH was identified in 3 environments.For yield related traits,a total of 22 yield traits better-parent QTL were detected in 4 environments,and 1 QTL for TKW on 5H(147-186cM)was identified in 3 environments.