Genetic Analysis And SSR Markers Associated With Quantitative Trait Loci For Fusarium Head Blight Resistance In Barley

Fusarium head blight (FHB) severity in the barley cross of Yan 96157 and Zhe 97-23 was analyzed by applying the major gene-polygene mixed inheritance model to a joint analysis of multi-generations (P1, F1, P2, B1, B2, F2). The combining ability of FHB resistance was also studied by a 4×4 diallel crossing of NCⅡ. In addition, simple sequence repeat (SSR) markers were screened in F2, F3 and F4 populations derived from the cross of Meilihuangjin and Epi 1 for FHB resistance quantitative trait loci (QTL). The results showed as follows:1. Genetic model of the resistance to Fusarium head blight in a novel resistant barley cultivar Yan 96157The FHB resistance in the cross of Yan 96157 and Zhe 97-23 was controlled by two major genes with additive-dominance-epistatic effects plus polygenes with additive-dominant-epistatic effects (E model). The major genes had high additive effects and obviously epistatic effects, in which the additive and dominance×dominance effects were favorable to enhance the FHB resistance in barley. Heritability values of major genes in B1, B2 and F2 populations were 44.67%, 68.01% and 83.87% respectively, while those of polygenes were 3.53%, 20.23% and 5.87% respectively. Variance of environment ranged from 10.26% to 51.80% in total variance, indicating the resistance to FHB was affected by both genotype and environment. Two major genes controlling the resistance to FHB in barley Yan96157 suggested that the resistant genes could be transferred to other commercial cultivars from Yan 96157 by conventional hybridization.2. Analysis of combining ability on resistance to Fusarium head blight in four novel barley cultivarsThe FHB resistance in barley fitted additive-dominance mode,mainly controlled by additive genetic components,with partial dominance effect. General combining ability (GCA) was more important than special combining ability (SCA) on FHB resistance in barley. Negative GCA effects of Phoenix,Yan 96157 and Jian 35 were similar and significantly decreased proportion of scabbed spikelets (PSS) of hybrid combinations. Broad sense heritability and narrow sense heritability were 76.27% and 57.81% respectively, indicating that it is feasible to select lines with FHB resistance in earlier generations.3. SSR markers associated with QTL for FHB resistance in a novel resistant barley cultivar Epi 1Narrow sense heritability in F2 and F3 populations derived from the cross of Meilihuangjin and Epi 1 were 43% and 51% respectively. Of the 292 SSR primers pairs screened, 43 pairs of primers (14.73%) showed polymorphism between Meilihuangjin and Epi 1. Eight SSR markers, which were located on chromosome 1H, 2H, 3H, 6H, 7H respectively, were identified to be associated with resistant QTL by single marker regression analysis. Six of the eight SSR markers mentioned above were from the resistant parent Epi 1. Markers Bmag0603, EBmag0794 and EBmac0853 had been detected at least in two populations, of which EBmac0853 detected in F3 population explained 11.34% of the variation in FHB resistance. These markers might be applied in marker-assisted selection (MAS) in barley breeding program.