Prolificacy and grain yield components in modern argentinian maize hybrids.

OTEGUI, M.E.

MAYDICA

Maydica

Lugar: Bergamo; Año: 1995 vol. 40 p. 371 - 376

0025-6153

ABSTRACT. The number of ears plant-1 is always considered as a selection criterion by maize plant breeders, and recent studies indicate that modern canadian hybrids have an increased number of ears plant-1. The objective of this work was to analyse the relationship between kernel number (KN) plant-1 and grain yield with prolificacy (ears plant-1) in a set of modern Argentinian hybrids. Sowing date (from August to November) and plant population (from 2 to 16 plants m-2) experiments were conducted at three sites (S1: 34°08´S; S2: 34°33´S; and S3: 37°45´S) in Argentina, on silty clay loam soils (Typic Argiudol) during 1990-1995, with no water or nutrient restrictions. Subapical ear contribution to KN plant-1 was greatest (P<0.05) with early sowings (Aug-Sep) and low plant populations (< 5.5 plants m-2), and increased significantly (r²= 0.867, n= 47) with increasing prolificacy. Spikelet abortion in the apical ear decreased (P<0.01) with increasing prolificacy. Nonprolific hybrids showed greater variability in the proportion of aborted spikelets in the uppermost ear (31 % ± 14) than the prolific ones (19 % ± 6). Changes in KN plant-1 were mainly related to the apical ear in prolific hybrids and to the subapical ear in the prolific types. Grain yield m-2 was always  associated with KN m-2, but two different (P<0.001) linear equations were fitted depending upon grain yield response to kernel weight. Increases in grain yield associated with the number of ears plant-1 of prolific hybrids can be achieved by the nonprolific ones through changes in KN of the apical ear and kernel weight.