Estimates of Combining Ability and Heterosis in Converted Exotic Sorghums1
- Paisan Laosuwan and
- R. E. Atkins2
The agronomic performance and breeding behavior of 11 restorer lines (R-lines) derived from sorghum (Sorghum bicolor L. Moench) conversion program materials were evaluated in four environments in Iowa. Data for grain yield and the primary components of yield were obtained from single crosses and three-way hybrids involving the R-lines as male parents.
For both types of hybrids, general combining ability (g.c.a.) effects of the R-lines accounted for the largest portion of the variation expressed for grain yield, hea~ls/~laent, 100-seed weight, and seeds/head. Significant tfcts for g.c.a. (females) were expressed for all characters in the single crosses, but this effect was significant only for seeds/head in the three-way hybrids. Variation attributable to specific combining ability (s.c.a.) effects provided the smallest contribution to the inheritance of all traits in both types of hybrids.
Heterosis for grain yield was greater than that for any of the components of yield. Mean heterosis and hetcrobeltiosis for yield in the single crosses averaged 49 and 37%. In average performance with all females, the single crosses with 10 of the 11 R-lines exceeded the mean yield of the check hybrid ‘RS 610’.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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