Desarrollo reproductivo en híbridos de maíz liberados entre 1980 y 2010 creciendo en condiciones contrastantes de disponibilidad de nitrógeno y densidad de plantas

MARIANO A. FERRARI; FERNANDA G. GONZÁLEZ; MARÍA A. ROSSINI

Pergamino

Congreso; Congreso Nacional de Maíz; 2018

AIANBA

Kernel number per ear (KNE) in maize crops is substantially less than the potential represented by the number of complete florets and the number of exposed silks per ear. This response is increased under stressful conditions that affect plant growth. Little is known about aspects of morphogenic development behind to the improved kernel number under stress conditions in modern hybrids. The objective of the present work was to analyze the variations of sub-components of morphogenic development of the ear (number of florets, exposed silks per ear, and kernel set) under contrasting conditions of N availability and stand density. We studied four hybrids released between 1980 and 2010 growing under combinations of stand densites (6, 9 and 12 pl m-2), and N availabilities (N0 without fertilization and N200 fertilized with 200 kg N ha-1). Silk emission explained variations in KNE in two hybrids (released in the decade of ´90 and ´00), mainly under low resources availabilities. The abortion of fertilized florets explained the variations in KNE of all hybrids. The most modern hybrid showed the lowest abortion values independently of resources availability. Both traits and their ecophysiological and/or genetic bases are promising for breeding for environments with low resources availabilities.