IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Inter-plant variation of grain yield components and kernel composition of maize crops grown under contrasting nitrogen supply
Autor/es:
MAYER, L.; ROSSINI, M.A. AND MADDONNI, G. A.
Revista:
FIELD CROPS RESEARCH
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 125 p. 98 - 108
ISSN:
0378-4290
Resumen:
Little information exists about the impact of N supply on inter-plant variability of grain yield per plant (GYP), GYP components (KNP: kernel number per plant; KW: kernel weight), and kernel composition, together with those of their physiological determinants, i.e. plant growth (PG) rate around silking (PGRS), PGRS per kernel (PGRS KNP-1) and PG during the effective grain-filling period per kernel (PGGF KNP-1). Two maize hybrids with contrasting tolerance to crowding (tolerant AX820 and intolerant AX877) were cultivated at high-stand densities (9 and 12 pl m-2) under contrasting N supplies (N0: control and N200: 200 kg N ha-1) without water restrictions. For AX877, plant-to-plant variability of PGRS exhibited a normal distribution in both N levels, and N fertilization only produced a displacement of data to higher PGRS values (0-5.5 and 1-6.6 g pl-1 d-1 for N0 and N200, respectively). For AX820, by contrast, the ranges of PGRS in N0 (1.0-7.4 g pl-1 d-1) and in N200 (1.2-7.4 g pl-1 d-1) were similar, but with a frequency distribution skewed to the right in N0 and with a normal symmetry in N200. The effect of inter-plant variability of PGRS on the coefficient of variation (CV) of KNP was of a greater magnitude order in AX877 than in AX820 due to the more linear KNP response to PGRS of the former. For both hybrids, mean values of KW increased and the CVs decreased in response to high N supply. Hybrid AX820 with the lowest KNP response to PGRS (i.e. highest CVs of PGRS KNP-1) had the largest CVs of KW. For each hybrid, differences among plants and N levels in KW were related to the duration of the effective grain-filling period. At low N supply, protein concentration decreased and starch concentration increased in response to the reduced PGGF KNP-1. Inter-plant variability of protein and starch concentration was higher in N0 than in N200, but that of oil concentration was not affected by N supply.