Heterosis and Combining Ability in Barley¹

Abstract

Eight parental varieties of barley and the 28 possible F1 and F1 populations were evaluated in spaced plantings in two environments. The traits studied were yield, kernel weight, kernels per head, heads per plant, and height.The average heterosis values of F1's based on midparent means for yield, kernel weight, kernels per head, heads per plant, and height were 21.5, 5.9, 7.1, 7.6, and 3.2%, respectively. When the F1's were compared to the high parent, the average heterosis for yield was 9.1%. The average inbreeding depression for yield in the F2 generation was 26.1%General and specific combining ability variances were obtained from the F1 data, using Griffing's experimental method 4, model II. A substantial amount of additive and nonadditive genetic variance for yield was indicated. Most of the genetic variance for kernel weight, heads per plant, kernels per head, and height was additive.The yield of the best hybrid exceeded the highest yielding parental varieties, Liberty and Traill, by 22 and 38%, respectively. A hybrid advantage of this degree combined with evidence of considerable nonadditive genetic variance for yield indicates the desirability of additional research on hybrid barley. The results reported indicated that performance per se can be used as a basis for initial screening in evaluating potential parental varieties for use in a hybrid breeding program.

Heterosis and Combining Ability of Barley Hybrids in Densely and Widely Seeded Conditions

“…The results were not as promising as those reported by This supports the finding that the hybrids responded difierently in the two environments. (12) and in wheat (I,7).…”

Heterosis and Hybrid Seed Production in Barley

“…Carleton and Foote (1968) did not find heterosisi for yield or for leaf area in tworow by six-row crosses, even though the parents differed reciprocally for components of yield and for components of leaf area. Upadhyaya and Rasmusson (1967) also found some hybrids that exhibited no heterosis for yield, even though the parents differed reciprocally for the components of yield. However, they did find several hybrids that exhibited heterosis which involved parents that showed reciprocal differences in yield components, as well as hybrids that exhibited heterosis from crosses where the parental varieties did not differ reciprocally for the components of yield.…”

“…Gustafsson and Dormling (1972) reported heterosis arising from interaction between maturity alleles at one locus, overdominance, in barley grown in a growth chamber, while Aastveit (1964) reported that heterosis found in the F 1 was ,based on non-allelic interactions and could be fIxed in true breeding form. Upadhyaya and Rasmusson (1967) reported data concerning heterosis and combining ability in the 28 F 1 and F 2 populations obtained from crossing 8 parental varieties in all possible combinations. They stated that a substantial amount of additive and non-additive genetic variance for yield was indicated.…”

“…The maximum amount of heterosis, as measured above the yield of the high-yielding parent, occurs in hybrids among low-yielding cultivars (Upadhyaya and Rasmusson 1967;Gebrekidan and Rasmusson 1970;Matchett and Cantu 1977). Lehmann (1982) states that specific combining ability is very important in hybrid barley.…”

Barley improvement

“…Unfortunately reports have sometimes been based on 'heterosis' relative to mid-parent values, using spaceplanted seeds, where the extra tillering capacity of the F 1 plant shows to advantage, which it does not do under normal agricultural conditions [66,140]. Thus large-scale agricultural trials are indispensable for evaluating this idea [131,158]. In one set of trials heterosis for forage was from 8 to 31% and for grain yields, 8-37%.…”