Articles

Effect of the few-branched-1 (Fbr1) tassel mutation on performance of maize inbred lines and hybrids evaluated under stress and optimum environments


Abstract


Yield can be increased under stress conditions by manipulating the traits that limit yield under these conditions. Tassel size is one such trait. A few branched-1 mutation (Fbr1) was introduced into the maize breeding programme of CIMMYT as a strategy to improve drought tolerance. The aim of this study was to evaluate yield performance of Fbr1 maize lines and hybrids under optimum and stress environments, and to determine associations between tassel size and grain yield under stress and optimum environments. Genotype effects were highly significant for all traits and genotype by environment (GxE) interaction effects were significant for all traits except for kernel row number and anthesis silking interval. Generally Fbr1 x Fbr1 hybrids had lower grain and pollen yields, and were less adapted to abiotic stress conditions. Positive relationships between grain yield components and pollen yield components were found except for association of prolificacy with tassel branch number and total tassel length under drought stress and optimum conditions. We were expecting that the Fbr1 genotypes could potentially in- crease grain yield under drought stress. It seems that grain yield improvement and stress tolerance is determined by multiple factors, which, when put together can additively contribute to increased yield performance. Although reduction in tassel size could be one of these many factors that contribute to improved grain yield under stress conditions, the factor cannot bring significant improvement on its own. Our results show that the Fbr1 trait reduce pollen production in genotypes with few tassel branches resulting in reduced kernel set and the problem worsens under drought and low N stress. We recommend selection for shorter and lighter tassels to improve grain yield without compromising on tassel size to ensure sufficient pollen availability, especially under stress environments.

Keywords

maize (Zea mays L), drought stress, low N stress, few-branched-1 (Fbr1) tassel mutation

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Maydica - A journal devoted to maize and allied species

ISSN: 2279-8013