Pollination asynchrony and kernel abortion in maize

CÁRCOVA, J.; OTEGUI, M.E.

CROP SCIENCE

Crop Science Society of America

Lugar: Baltimore; Año: 2001 vol. 41 p. 1809 - 1815

0011-183X

Maize (Zea mays L.) kernel set can be improved through synchronous pollination within and between ears. Reductions in kernel set could be expected due to asynchronous pollination between early- and late-appearing silks. We analyzed the effect of (i) selective ear heating around silking, and (ii) different time gaps between early- and late-pollinated silks in an attempt to modify kernel set. Tip ear heating was expected to minimize the advantage of early silking ovaries. Lateral heating and pollination gaps were expected to exaggerate this advantage. Three pollination gaps (2, 4, and 6 days) were tested for two plant populations (3 and 9 plants m-2). Ear temperature in the heated zone averaged 4.5 °C above air temperature. Temperature in the non-heated side closely followed air temperature. Treatments promoted greater differences in KN ear-1 (73 % variation) than in the number of silks exposed 5 days after silking (6% variation). Lateral ear heating reduced KN ear-1 inin comparison with the non-heated control, but tip ear heating did not modify KN ear-1. At 9 plants m-2, synchronous pollination resulted in ~15% increase in KN plant-1.  Pollination gaps of 2 and 4 days reduced KN plant-1 drastically (up to 51%), but the reduction was smaller for the 6-day gap. This study (i) gives evidence of the negative impact of delayed pollination timing among silks on kernel set, which was not related to reduced silk receptivity, and (ii) defines the time gap for maximum interference of early- on late-pollinated ovaries, a period shorter than 4 days.in comparison with the non-heated control, but tip ear heating did not modify KN ear-1. At 9 plants m-2, synchronous pollination resulted in ~15% increase in KN plant-1.  Pollination gaps of 2 and 4 days reduced KN plant-1 drastically (up to 51%), but the reduction was smaller for the 6-day gap. This study (i) gives evidence of the negative impact of delayed pollination timing among silks on kernel set, which was not related to reduced silk receptivity, and (ii) defines the time gap for maximum interference of early- on late-pollinated ovaries, a period shorter than 4 days.