Combining ability of maize grain yield under different levels of environmental stress

Pesquisa Agropecuária Brasileira

Leandro Vagno De Souza²  Glauco Vieira Miranda¹  João Carlos Cardoso Galvão¹  Lauro José Moreira Guimarães¹  Izabel Cristina Dos Santos¹ 

[1] ,Dow AgrosciencesJardinópolis SP ,Brazil

关键词: Zea mays;    abiotic stress;    breeding;    diallel;    drought;    Zea mays;    estresse abiótico;    melhoramento;    dialelo;    seca;   

DOI  :  10.1590/S0100-204X2009001000013

来源: SciELO

【 摘 要 】

The objectives of this work were to caracterize the tropical maize germplasm and to compare the combining abilities of maize grain yield under different levels of environmental stress. A diallel was performed among tropical maize cultivars with wide adaptability, whose hybrid combinations were evaluated in two sowing dates, in two years. The significance of the environmental effect emphasized the environmental contrasts. Based on grain yield, the environments were classified as favorable (8,331 kg ha-1), low stress (6,637 kg ha-1), high stress (5,495 kg ha-1), and intense stress (2,443 kg ha-1). None of the genetic effects were significant in favorable and intense stress environments, indicating that there was low germplasm variability under these conditions. In low and high stresses, the specific combining ability effects (SCA) were significant, showing that the nonadditive genetic effects were the most important, and that it is possible to select parent pairs with breeding potential. SCA and grain yield showed significant correlations only between the closer environment pairs like favorable/low stress and high/intense stress. The genetic control of grain yield differed under contrasting stress environments for which maize cultivars with wide adaptability are not adequate.

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