Relaciones hídricas del grano y control de la duración del período de llenado en híbridos de maíz.

GAMBÍN, B.L.; BORRÁS, L.; OTEGUI, M.E.

Rosario, Santa Fe, Argentina

Congreso; VIII Congreso Nacional de Maíz.; 2005

A.I.A.N.B.A.

Kernel water relations play a key role in the control of grain-filling duration. The moment when maximum water content (MWC) is attained defines the duration by determining the timing when kernels remain above the critical moisture content at which biomass accumulation stops. However, recent results in sorghum have shown that the pattern of kernel water content replacement by biomass once MWC is reached can also affect the timing when this critical moisture content is attained. We tested if genotypic differences in maize grain-filling duration were related to differences in the moment when MWC was reached or in the desiccation pattern of kernels during late grain filling. We also tested genotypic differences in the capacity to generate kernel volume late in kernel development. Twelve commercial hybrids were evaluated, and kernel weight, kernel water content and kernel volume were measured. In order to address differences in kernel desiccation, we calculated a ratio between the kernel dry matter accumulated and the kernel water content from MWC to physiological maturity. Genotypes showed no difference in the moment when MWC or maximum kernel volume was reached; maximum kernel volume was always achieved later in development than MWC. Genotypic differences in grain-filling duration were related to variations in the calculated desiccation ratio, showing that kernel water relations during late grain filling affected the duration of grain filling. Differences in the desiccation ratio were related to differences in the capacity to generate kernel volume once MWC is reached, suggesting that the capacity of the kernels to continue expanding during late grain filling might be playing a key role in maize grain-filling duration.