Effects of plant density on growth parameters and yield of sugar bean (Phaseolus vulgaris L.) in Swaziland

Abstract

Field bean (Phaseolus vulgaris L.) consumed in Swaziland is mostly imported. Small- scale farmers can grow this crop in the country and obtain good yields if the correct planting density is identified. A field study was conducted during the growing season of 2004/2005 to determine the influence of different planting densities on growth parameters and yield of field bean. The experiment consisted of a randomised complete block design, with four replications. There were five planting densities (400,000; 200,000; 133,333; 100,000 and 66,667 plants/ha studied for 11 weeks. Results showed that Absolute Growth Rate (AGR) was significantly (P < 0.01) higher in the lower populations. The lowest population had AGR of 7.0 g/week whereas the highest plant population had AGR of 2.4 g/wk between 7 and 10 weeks after planting (WAP). At 7 WAP, the highest plant population had a significantly (P <0.01) higher leaf area index, LAI, of 4.6 while the lowest plant population had LAI of 0.7. At 400,000 density of plants/ha, though the seed yield (695.8 kg/ha) was low, however, it was 56% higher than the yield (445.5 kg/ha) of the recommended plant population. Planting density of 400,000 plants/ha is suggested.