Heterosis, Inbreeding Depression, and Heritability Estimates in a Systematic Series of Grain Sorghum Genotypes¹

Abstract

Ten genetic sets of grain sorghum (Sorghum bicolor L. Moench) each consisting of two pure lines, their F1, F2, and first backcrosses were studied at two locations in two years. Of characteristics observed, grain yield showed the highest heterosis [(F1—better parent)(100)/better parent] as averaged over the 10 sets and likewise had the greatest inbreeding depression [(F1—F2) (100)/F1]. Heterosis was low for plant height and negative for days‐to‐first‐bloom and kernel weight. Narrow sense heritability estimates, for the F2 generation, varied among sets. The estimates for days‐to‐first‐bloom, plant height, and kernel weight were relatively high. In contrast, grain yield had low heritability. Expected genetic advance in F3 yield under selection, was higher than actual advance for most sets, suggesting epistasis.

Hybrid performance of sorghum and its relationship to morphological and physiological traits under variable drought stress in Kenya

“…It is therefore imperative to improve the genetic resistance of heterozygotes to lodging under terminal drought stress. The observed effects of heterozygosity for characters other than grain yield generally support previous findings in sorghum (Kambal and Webster 1966, Kirby and Atkins 1968, Liang et al 1972.…”

“…Lower values were drought stress was found by Flower et al (1990) and Tangusually obtained with crosses of adapted parent hnes (Kambal p^emsri et al (1991 a,b) for sorghum and by Guei and Wassom and Webster 1966, Kirby and Atkins 1968, Reich and Atkins (1993 fo^ maize (Zea mays L.). Similarly, populations of mea-1970, Liang et al 1972), while high estimates were most often ^ow fescue (Festuca pratensis Huds.) ranked differently when reported from studies that involved exotic germplasm (Niehaus evaluated for drought resistance in pots from which water was withheld, and in the laboratory under artificial osmotic stress (Thomas et al 1996).…”

Dissecting repulsion linkage in the dwarfing gene Dw3 region for sorghum plant height provides insights into heterosis

“…Sorghum plant height shows 6-72% high-parent heterosis (23)(24)(25)(26)(27)(28). In maize, high-parent heterosis of plant height can reach 32-120% (13,29,30).…”

Yield and Yield Stability of Four Population Types of Grain Sorghum in a Semi‐Arid Area of Kenya

“…Similarly, heritability estimates were found to be slightly lower under of all reported cases in barley (Hordeum vulgare L.), the superiority of mixtures was statistically significant. stress conditions for grain yield in wheat (Ud-Din et al, 1992) and pearl millet (Bidinger et al, 1994), and Blending reduced estimated entry ϫ environment interaction variances and deviation mean squares at the independent from the stress intensity for grain yield of barley (Ceccarelli et al, 1987;Ceccarelli, 1994). homozygous but not at the heterozygous level.…”