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Genetic Variances and Heritabilities of Traits of an Early Yellow Maize Population after Cycles of Improvement for Striga Resistance and Drought Tolerance
Author(s) -
Badu-Apraku B.,
Ifie B. E.,
Talabi A. O.,
Obeng-Bio E.,
Asiedu R.
Publication year - 2018
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2017.10.0628
Subject(s) - biology , striga , agronomy , drought tolerance , population , selection (genetic algorithm) , genetic variability , anthesis , yield (engineering) , genetic gain , genetic variation , genotype , cultivar , genetics , demography , germination , materials science , artificial intelligence , sociology , computer science , gene , metallurgy
Drought and Striga are principal constraints to maize ( Zea mays L.) production in sub‐Saharan Africa. An early yellow maize population, TZE‐Y Pop DT STR, which had undergone five cycles of selection for resistance to Striga , followed by three cycles of improvement for drought tolerance, was investigated for yield gains, changes in genetic variance, and interrelationships among traits under drought stress and optimum environments. Two hundred and forty S 1 lines comprising 60 each from the base population and subsequent populations from three selection cycles improved for grain yield and drought tolerance were assessed under drought and optimal environments in Nigeria from 2010 to 2012. Genetic improvements in grain yield of 423 and 518 kg ha −1 cycle −1 were achieved under drought stress and optimal environments. Predicted improvements in selection for yield were 348 and 377 kg ha −1 cycle −1 under drought stress and optimum environments, respectively. The highest yield observed in C 3 was accompanied by reduced days to silking and anthesis–silking interval, improved plant aspect and ear aspect, and increased plant height and ears per plant across research environments, as well as improved stay‐green characteristic under drought. The level of genetic variability for yield and a few other traits were maintained under drought and optimal environments in the population. The presence of residual genetic variability for yield and other assayed traits in C 3 indicated that progress could be made from future selection in the population depending on the ability of breeders to identify outstanding genotypes and the precision level of experimentation. Substantial improvement has been made in yield and drought tolerance in C 3 of the population.