Browsing by Author "Talabi, A.O."
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Item Gains in Grain Yield of Extra-Early Maize during Three Breeding Periods under Drought and Rainfed Conditions(Crop Science, 2018-07) Badu-Apraku, B.; Talabi, A.O.; Ifie, B.E.; Chabi, Y.C.; Obeng-Antwi, K.; Haruna, A.; Asiedu, R.12 Drought is a key maize (Zea mays L.) production constraint in sub-Saharan Africa (SSA). Fourteen, 13 15 and 25 extra-early maturing maize cultivars, with varying Striga resistance, drought and low soil 14 nitrogen tolerance, were developed from 1995 to 2000 (Period 1), 2001 to 2006 (Period 2) and 2007 to 15 2012 (Period 3), respectively. The objectives of this study were to examine yield gains in the cultivars, 16 investigate inter-trait relationships and yield stability under six drought and 17 rain-fed conditions in 17 West Africa, 2013-2016. Annual rate of yield increase across cultivars was 0.034 Mg ha-1 (3.28 %) 18 and 0.068 Mg ha-1 (2.25 %) while yield gains per period were 0.17 and 0.38 Mg ha-1 under drought and 19 rain-fed environments, respectively. Yield gains under drought and rain-fed environments were related 20 to prolonged flowering period, increased plant and ear heights, improved stalk lodging, ear and plant 21 aspects, whereas delayed leaf senescence and increased number of ears per plant (EPP) accompanied 22 yield improvement under drought only. Ear aspect and EPP were primary contributors to yield and 23 could be used as selection criteria for yield enhancement under drought and rain-fed conditions. High 24 yielding and stable cultivars across all environments based on additive main effects and multiplicative 25Item Genetic variances and heritabilities of early yellow maize population following cycles of improvement for Striga resistance and drought tolerance(Crop Science, 2018-07) Badu-Apraku, B.; Ifie, B.E.; Talabi, A.O.; Obeng-Bio, E.; Asiedu, R.Drought and Striga are principal constraints to maize production in sub-Saharan Africa. An early yellow maize population, TZE-Y Pop DT STR that 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 variances and interrelationships among traits under drought-stress and optimum environments. Two hundred and forty S1 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, 2010 – 2012. Genetic improvements in grain yield of 423 and 518 kg ha-1 cycle-1 were achieved under drought-stress and optimum 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 C3 was accompanied by reduced days to silking, anthesis-silking interval, improved plant aspect, 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 some few other traits were maintained under drought and optimal environments in the population. Presence of residual genetic variability for yield and other assayed traits in C3 indicated that progress could be made from future selection in the population depending on the ability of breeders to identify outstanding genotypes and precision level of experimentation. Substantial improvement has been made in yield and drought tolerance in C3 of population.