Untitled

Abstract

Low and erratic rainfall constitutes a major constraint to sorghum production, and impedes sorghum improvement in semi-arid tropics. To estimate quantitative-genetic parameters for sorghum under variable stress conditions, three sets of factorial crosses between four by four lines each were grown with parents and a local cultivar in eight macro-environments in semi-arid areas of Kenya. Fourteen traits were recorded including grain yield, above-ground drymatter, harvest index, days to anthesis, leaf rolling score, and stay-green. Environmental means for grain yield ranged from 167 to 595 g m −2. Mean hybrid superiority over midparent values was 47, 31, and 9% for grain yield, above-ground drymatter, and harvest index, respectively. Differences among both lines and hybrids were highly significant for all traits. Genotype × environment interaction variances were larger than genotypic variances for grain yield, above-ground drymatter, and harvest index. Corresponding heritabilities ranged between 0.72 and 0.84. Variation among hybrids was determined by GCA and SCA effects for most characters. Predominance of additive-genetic effects was found for grain yield components, plant height, and leaf rolling score. Lack of variation in GCA was noted among female lines for major performance traits. While low leaf rolling score was correlated with high grain yield, there was no such association for stay-green. Hybrid breeding could contribute to sorghum improvement for semi-arid areas of Kenya. To increase selection progress for major performance traits, genetic variation among female lines should be enhanced. Importance of genotype × environment interaction underlines the necessity of evaluating breeding materials under a broad range of dryland conditions.

Combining ability and heterosis using line by tester analysis on some hybrids of grain sorghum under normal and saline soil

“…In general, crosses which had positive and significant SCA effects for grain yield per plant were high in grain yield per plant. These results are in line with those reported by Haussmann et al, (1999), Mahmoud (2002), Amir (2004), Mahmoud (2007), Amir (2008), Mahmoud et al, (2013), Tag El-Din (2015) and El-Sagheer (2019). For the percentage of protein, the crosses no.…”

Evaluation of Yield Potential and Combining Ability in Thai Elite Cassava Varieties for Breeding Selection

“…The difference between GCA and SCA was calculated by considering the standard error and referring to the tabulated t-value. Additionally, the GCA:SCA ratio was determined by comparing the mean squares of GCA and SCA [24,25]. The Baker's (BR) ratio was also calculated, with a value above 0.5 indicating that additive gene effects are more prominent than dominant effects [26].…”

Combining Ability and Heterosis Estimation in Elite Sorghum [Sorghum bicolor (L) Moench] Inbred lines Under Moisture Stress Areas of Ethiopia

“…23.05 to 51.50%,-19.20 to 142.40%and 15.43 to 104.57% over mi-parent, better parent and standard check respectively. From the obtained results, hybrids have more tolerance to abiotic stress and resistance to premature leaf and stalk death induced by post-owering drought(Crasta et al, 1999).…”