Heterosis And Genetic Analysis Of Principal Traits In Barley (Hordeum Vulgare L.)

The performances of barley hybrid F₁ and correlated with its parents, the characteristics of heterosis and associated with the row-types of parents,and the combining ability and concerned genetic parameters for 13 quantitative traits, including plant height (abbreviated to PH), spike length excluding awns(SL), rachis inter-node length (RIL), spikes per plant(SP), kernels on main spike(KMS), kernels per spike(KPS), kernels per plant(KP), kilo-grain weight(KW), kernel weight per plant(KWP), dry matter weight per plant(DWP), kernel yield(KY), protein content (PC)and lysine content(LC) in kernels, were investigated in 9 CMS lines and corresponding maintainers, 9 restorers and their 7x4=28, 5x5=25, 7x5=35, total 88 F₁ hybrids which distributed in three field experiments from 1999 to 2003. All CMS lines, maintaners and restorers are newly bred by Barley Research Institute of Yangzhou University. The results are summarized as follows.(1) Most traits had significantly genetic difference among parents, and their hybrids F₁'s usually had the superiority over high-parent in the agronomic and yield component traits. However, the linear correlation degree of the average ofF₁ with that of its male and female parents was less than the alienation degree in most traits. The fact suggests that it should be difficult to precisely predict the performance of F₁ from the phenotypic value of its male and female parents.(2)The heterosis of hybrid F₁ from mid-parent value, H_m, often existed and the occurrence rates of positively and negatively significant H_m were 46% and 12%, respectively. But the occurrence rate of the significant H_b , the heterosis of hybrid F₁ over better parent value, was 28% on average, ranging from 0% (PH and KMS) to 79% (IL), varied with the traits. In the present study, the crosses of 3×13,3×18,3×19, 5×11, 5×17, 5×l9and 8×17 had strong heterosis.(3)The hybrids from 2-rowx2-row barley had longer spike, more spikes per plant and higher kilograin weight, and 6-rowx6-row hybrids had more kernels per spike and plant, and higher kernel yield than 2-rowx2-row hybrids. Hybrids in hetero-row mating group(2-row X 6-row and 6-row X 2-row) tended to be longer culm and rachis internode, and heavier kernel weight, and might easily produced biomass superiority, compared with that in homo-row mating group .The homo-row mating hybrids (i.e., 2-row×2-row and 6-row×6-row) were benefit to economic yield superiority.(4) Combined the general combining ability with mean squares (MS) of specific combining abilities of 13 traits . The maintainer 3B and its CMS line as well as restorers 15R were the most ideal parents. The maintainer 2B,9B and their CMS lines as well as restorers 17R and 18R were ideal parents. The maintainer 1B, 4B, 6B, 7B and their CMS lines and restorers 16R were less worth for utilization because of their lower general combining ability and less MS of specific combining abilities. The others were regarded as general parents.(5)The significant additive effect existed in most traits of parents, but theadditive effect for male parents (restorers) was larger than that for females (maintainers). The performances of hybrid F₁ in traits PH, SL, RIL, SP, KP, KW, KWP and DWP tended to higher parent, and tended to lower parent in traits KMS and KPS. For genetic background effect, female parent was preferable in PH and KGW traits, and male was preferable in KMS, KPS, KP, KWP and DWP traits. Most traits had higher broad heritability, ranging from 0.194 to 0.992. but SP, KWP and DWP traits were easily affected by environment.