Row width and maize grain yield

MADDONNI, G. A.; CIRILO, A.G., AND OTEGUI, M. E

AGRONOMY JOURNAL

American Society of Agronomy

Lugar: Madison, Wisconsin ; Año: 2006 vol. 98 p. 1532 - 1543

0002-1962

Maize (Zea mays, L.) grain yield (GY) increase in narrow rows (NR) is related to the improvement of light capture around silking, but percentages of GY increase are generally lower than those of light interception, suggesting a lower efficiency to convert the amount of intercepted photosynthetic active radiation (IPAR) into biomass. We analyzed the effects of plant population x row spacing on GY and its components, (i.e. kernel number (KN) and kernel weight (KW), and on the underlying processes, i.e. the IPAR around silking and during the effective grain filling period, and radiation use efficiency (RUE) during both periods. Field experiments were conducted in Argentina from 1997 to 2001. Five hybrids with contrasting KW (small KW<300 mg per kernel and large KW>300 mg per kernel) were cultivated at a wide range of plant population densities (3, 4.5, 9 and 12 pl m-2) and row spacings (0.35, 0.50, 0.70 and 1m). An enhanced IPAR around silking in NR was mainly recorded at low plant densities (ca. 8% and 4% for 3-4.5 and 9-12 pl m-2, respectively, P<0.05), where maximum leaf area index (LAI) values (2.46-3.79) were below the critical LAI (¡Ö4). Morphogenetic limitations in the reproductive organs of plants cultivated at low stand densities suppressed the slight benefits of enhanced light capture under NR, yielding  similar KNs and GYs at any row spacing. The post-silking RUE reduction (ca. 13-16%, 0.001<P<0.01) recorded in NR limited crop growth during the grain-filling period, which was reflected (P<0.05) in KW (208 vs 225 mg per kernel for NR and wide rows (WR), respectively) and GY (1021 and 1089 g m-2 for NR and WR, respectively) of small KW hybrids.