Water regime variability during the flowering phenophase of white and yellow grain maize hybrids and the relation with grain yield

Variabilidade do regime hídrico durante a fenofase de florescimento de híbridos de milho de grãos brancos e amarelos e sua relação com a produtividade de grãos

ABSTRACT

The impact of low water availability on maize yield depends on the severity of the water deficit and the phenological stage of the crop. The objective of this study was to evaluate the variability of the water regime during flowering in white (GB) and yellow (GA) maize hybrids and its effects on grain yield. The study was conducted under field conditions in a pelic vertisol soil in Celaya, Guanajuato, Mexico. The drought condition of the crop was 75% of soil humidity with a soil water potential of -1.5 MPa. Hydraulic conductivity (Lp), water (Ψr) and osmotic (Ψs) potentials of the roots (during flowering phenophase), grain yield and water productivity were the evaluated variables. As results, significant variability of the water regime variables was obtained among the evaluated hybrids, resulting in variation of grain yield. The white-grain hybrids with the highest Lp were GB4 and GB5 and for yellow-grain GA2 and GA10, all exceeding 347.75 mg m^-1 s^-1 MPa^-1. In some hybrids Ψr and Ψs, decreased to more than -1.85 and -2.80 MPa, respectively, showing positive responsiveness during flowering to the drought condition of the soil. There was positive and significant correlation between Lp x Yield, and highly significant negative correlation between Ψs x Yield. The highest yielding hybrids were GB4 (8000 kg ha^-1) and GA2 (7800 kg ha^-1). These hybrids will continue to be evaluated for other variables for validation and recommendation for drought conditions.

Index terms:
Hydraulic conductivity; osmotic potential; water potential; Zea mays L.