Estimation of Heterosis and Combining Ability Effects on Grain Yield and Some Agronomic Traits of Sorghum under Three NPK Fertilizers Levels

Abstract

ETEROSIS and combining ability for grain yield and some …….agronomic traits were studied among thirty F1 grain sorghum crosses and their elven parents under three NPK levels during 2014 and 2015 seasons. Significant differences among genotypes were found for all studied traits, indicating wide genetic diversity. The interaction of genotypes with each of years and NPK levels were significant in most studied traits. The analysis of variance for combining ability revealed that the mean square due to entries, parents, parents vs. crosses, crosses, lines, testers, lines × testers turned up significant for all studied characters and suggesting that the experimental materials possessed considerable variability that both general and specific combining ability were involved in the genetic expression of these characters. The female line ICSB610 showed significant and negative general combining ability (GCA) effects for days to 50% heading and panicle length and positive for grain yield and plant height. It may be used to develop high yielding, early flowering, and tall hybrids with short panicles. For specific combining ability (SCA), effects, the crosses ICSA613 × ICSR89028 and ICSA20 × ICSR53 gave positive and highly significant SCA effects which indicated that these crosses can be considered desirable combiners. These crosses had also high grain yield per se and one of the parents with highest GCA effects. The observations on portioning of combining ability variance into additive and dominance variances indicated the role of both additive and dominance gene action. The magnitude of non-additive variance was higher than the additive variance by many folds for all studied traits.

Combining ability and heterosis studies in different crop sites for yield and yield contributing traits in sorghum (Sorghum bicolor (L.) Moench)

“…The estimates of σ 2 sca were more than σ 2 sca for all the traits studied and the ratio of σ 2 sca/ σ 2 gca is more than unity indicating non-additive gene action operating in the inheritance of yield contributing traits. Similar results have also been reported in sorghum by Mengistu et al (2020), Kumari et al (2018), Akata et al (2017), Sayed and Said (2016), and Aruna et al (2010). The findings of this study, such as non-additive genetic variance for grain yield and yield components, suggested that in early generations of sorghum, selection and accumulation of desired alleles for the enhancement of yield and yield components is likely to be effective.…”

“…The general combining ability effects (Table 2) revealed that among the lines ISCA 435 and ICSA 433 were good general combiners for days to 50 % flowering, days to maturity and plant height. For 100 seed weight, ICSA 418 and ICSA 419 were good general combiners whereas, lines ICSA 427 and ICSA 433 were found to be good general combiners for grain yield per plant, grain yield per Sayed and Said (2016), Aruna et al (2010) and Kenga et al (2004).…”