Combining Ability for Quantitative Traits Under Normal And Heat Stress Conditions in Maize (Zea Mays L.)

Abstract

Investigation was carried out to ascertain the genetic architecture for heat tolerance and yield components from diallel crosses in maize (Zea mays L.). The combining ability in both the normal and heat stress conditions revealed highly significant mean squares due to general combining ability (GCA) and specific combining ability (SCA) in both the direct and reciprocal crosses for all the characters except for anthesis-silking interval in normal condition of the reciprocal crosses. Estimate of components of variance for 13 characters revealed higher SCA variance than that of GCA and reciprocal crosses for all the characters. CML 411 was good general combiner for grain yield in both the conditions, whereas, CML 306 and CML 307 were good general combiners in heat stress condition, and CML 164, CML 304 and CML 305 were average general combiners in normal condition. On the basis of high yield, high SCA and at least high GCA of seed parent, the CML 411*CML 305 and CML 411*CML 307 were identified as promising hybrids for normal and heat stress conditions, respectively. Bangladesh J. Bot. 50(3): 659-669, 2021 (September)

A Study on the Specific Combining Ability in Several Inbred Lines of Maize

“…An F-test was conducted to study the effect of genotype. Analysis of Line x Tester used quantitative genetic analysis by SCA criteria as follows: (1) positive and high if SCA is positive and equals/ more than one of its standard error, (2) negative and high if SCA is negative and equals/more than one of its standard error, (3) positive and low if SCA is positive and less than once of its standard error, and (4) negative and low if SCA is negative and less than once of its standard error (Akula et al, 2016;Bhusal & Lal, 2020;Natol, 2017;Rani et al, 2018;Yadesa et al, 2021).…”

“…General combining ability (GCA) and specific combining ability (SCA) may have positive and negative effects. Positive means that the inbred lines or the hybrids are better than the negative ones (even have the same traits), while negative means that the inbred lines or the hybrids, with the same characteristics, are inadequate in comparison with the positive ones (Karim et al, 2018;Natol, 2017;Rani et al, 2018). The problem in assembling maize hybrid varieties is the proper selection of inbred lines.…”

Genetic Potential of Tropically Adapted Exotic Maize (Zea mays L.) Heat-Tolerant Donor Lines in Sub-Tropical Breeding Programs

“…Climate projections show that heat stress frequency, duration, and severity is increasing and that a temperature rise of 0.3 • C is expected to reach approximately 1 • C above the present value by the year 2025 [6,7], and this will cause a decline in global maize grain yield potential by 45% [8]. Hence, acceleration of breeding for heat stress tolerance became a priority objective in maize breeding to ensure food security under these predicted climatic scenarios [9].…”