Combining abilities and genetic parameters for grain yield and some agronomic traits in maize (Zea mays L.)

摘要

Background The improvement of maize hybrids relies on significant genetic variability among the inbred lines used and the degree to which it is transferred to progeny. Understanding the genetic parameters and heritability of traits in every population is an essential precondition for selection program. This study was designed to estimate the magnitude of genetic parameters and heritability of traits in line x tester mating design. Fifteen yellow maize inbred lines derived from different sources were crossed with two lines as tester i.e., Gm-1001 and Gm-1002 in 2019 summer season. During 2020 season, the resulted 30 crosses along with check hybrid SC-168 were evaluated in a yield trial at two locations: Gemmeiza and Sids Agric. Res. Station. Results The mean squares among two locations were highly significant for all studied traits except KR-1. The L-1 and L-3 had the best general combiners for GY ard fed(-1). In addition, the T-1 as a tester was a GCA effects good combiner for earliness, shorter plants and lower ear placement traits. While T-2 was good combiner for grain yield and some of attributes. Crosses L-5 x T-1 and L-7 x T-2 had positive and significant SCA effects for grain yield. The GCA variances were higher than SCA variances for all studied traits except for ED trait, indicating that additive genetic variance played the major role than non-additive genetic variance in the inheritance of these traits. Generally, phenotypic coefficient of variability was higher than genotypic coefficient of variability for all studied traits, suggesting that there was an influence by environments in the expression of these traits. Recorded heritability percentage in broad sense ranged from low for (ear position, no. of ears/100 plants, ear diameter and grain yield) traits, medium for (days to 50 silking, plant height, ear height and no. of kernels/row) traits to moderate high for ear length trait. Conclusion Our investigation concluded that most of the studied lines exhibited highly general combiners and the superior crosses were as a result of a good x good combiner for most of yield components traits.