Heterotic Response for Vegetative and Mature Plant Characters in Grain Sorghum, Sorghum bicolor (L.) Moench¹

Abstract

Comparative expressions of heterosis for 13 vegetative and mature plant characters were examined from 24 F1 hybrid populations of grain sorghum. Significant average heterosis was expressed by the hybrids for grain yield, mature plant height, stalk diameter and for measures of height and leaf number taken at a vegetative growth stage. Hybrids also exhibited longer and wider leaves giving more area per leaf, earlier blooming, more seeds per head, increased numbers of heads per plant and larger seed, but significance was not shown for the hybrid advantage in comparison with the parental means.Significant variation among hybrids for percentage heterosis was expressed for all characters except stalk diameter, seeds per head and heads per plant. Greatest heterotic response was observed for grain yield where hybrids averaged 122% of the mid‐parent values, with a range of 106 to 147% among individual hybrids.Variance analyses indicated that general combining ability effects were more often significant than were specific combining ability effects. However, significance for the s.c.a, component was shown for 6 of the 13 characters, and the mean square for parents vs. hybrids was significant for 5 of the characters, indicating that non‐additive gene effects were important in the expression of these traits.Inter‐character correlations among hybrids indicated that seeds per head was the character most highly associated with grain yield. Correlations between the mid‐parent mean and hybrid performance were significant for each character, but the coefficients for many of the characters were not large enough to indicate that mid‐parent values would be highly effective indicators of hybrid performance.

Combining ability and heterotic pattern in West African sorghum landraces

“…These results were in agreement with findings of Kenga et al (2004) reporting on prevalence of non-additive variance for days to anthesis, plant height, inflorescence length and grain yield per plant. Contrary to our study, earlier works have reported that additive gene effects were a predominant factor determining grain yield in sorghum (Beil and Atkins, 1967;Kirby and Atkins, 1968). The previous studies used breeding lines or previously characterized genotypes with known behaviour in cross.…”

Prediction of hybrid performance in grain sorghum using RFLP markers

“…Estimates of mid-parent heterosis for grain yield in sorghum range from 6 to 54% (Kirby and Atkins 1968;Walter 1968, 1969;Wenzel 1988). Generally the advantage of hybrids is in the order of 30-40% which is less than the figure of approximately 50% observed in maize (Duvick 1999).…”

“…Generally the advantage of hybrids is in the order of 30-40% which is less than the figure of approximately 50% observed in maize (Duvick 1999). Maturity, height and stay green also exhibit heterosis with estimates of mid-parent heterosis varying from -1 to -6% for maturity and 5 to 19% for height (Kirby and Atkins 1968;Liang and Walter 1968;Wenzel 1988). van Oosterom et al (1996) observed heterosis of 27% for absolute green leaf area duration which is highly correlated with stay green.…”

Quantitative‐genetic parameters of sorghum growth under striga infestation in Mali and Kenya

“…The superior yield of the F 2 populations over the corresponding homozygous parents points to the potential merit of heterozygous cultivars for striga-infested areas in Mali and Kenya. Earlier anthesis and increased plant height compared with the parents are other characteristic eects of heterozygosity in sorghum (Bartel 1949, Kirby and Atkins 1968, Blum et al 1990, Haussmann et al 1998. The reaction to striga of the F 2 populations relative to their parents varied with the parental combination.…”