Influence of sowing date and irrigation on the growth and yield of pinto beans (Phaseolus vulgaris) in a sub-humid temperate environment

Abstract

The growth and yield of pinto beans (Phaseolus vulgaris L.) cv. Othello in response to a total of six sowing dates (from October to December) and irrigation was examined over two seasons in Canterbury, New Zealand. In 1994/95, two irrigation treatments (nil and full) were combined with two sowing dates (27 October and 24 November). In 1995/96, Othello was examined under two irrigation treatments (nil and full) and four sowing dates (1 November, 15 November, 29 November and 13 December). The total rainfall for the two seasons was 50% and 60% of the long-term average, respectively. The mean temperatures for the seasons were similar to the long-term average. Both irrigation and sowing date had a marked effect on growth and seed yield. Averaged over both seasons, seed yield for fully irrigated crops was 337 g/m2, c. 50% higher than the yield of unirrigated crops. The irrigated crops yielded more than the unirrigated crops because they attained greater canopy closure, intercepting 84–95% of incident radiation. They also had on the average 47% higher leaf area duration (LAD), 72% higher maximum leaf area index (LAI) and greater utilization coefficient. The mid- to late November-sown crops yielded more than the late October to early November and December-sown crops because the leaf area of the former increased most rapidly, achieved a higher maximum LAI and LAD and consequently intercepted more photosynthetically active radiation (PAR). They also had faster pod growth rates and 26% of stored assimilates contributed to pod growth compared with 13% in late October to early November and 5% in December-sown crops. The results showed that pinto beans can grow and yield well in Canterbury, and that a yield advantage could be obtained when sown in mid- to late November and with irrigation.