Plant Population Effects on the Seed Yield of Phaseolus vulgaris L.1

Abstract

AbstractSeed yields of Phaseolus vulgaris L. have not increased under the current production systems even with more precise management inputs. Recent studies of snap beans grown for processing suggested that yields could be increased by high density planting. Our study was made to evaluate the effects of plant populations on the seed yields of four representative field and snap bean cultivars grown under sprinkler irrigation on a Portneuf silt loam (Xerollic Calciorthid).Two cultivars each of bush snap beans and semivining field beans were grown in plant populations of 107,600 to 968,700 plants/ha in nearly equidistant plant arrangements. The optimum plant population for seed yield for the bush cultivars was approximately 400,000 plants/ ha and less than 300,000 plants/ha for the semivining cultivars. At smaller plant populations, seed yields decreased for the bush cultivars and remained constant for the semivining cultivars. The harvest index (seed weight/ total plant weight) increased slightly for the bush cultivars as their plant population decreased, but remained constant for the semivining cultivars up to 300,000 plants/ ha, then increased rapidly. The production index (seed yield/amount seeded) increased curvilinearly as plant population decreased for all cultivars. Plant maturity was advanced 7 to 10 days at the highest plant populations for all cultivars. Pods were located at upper nodes on the plants as the populations increased. These results suggest that greater seed yields could be expected with the equidistant plant arrangements as compared with conventional row plantings for the bush cultivars, but not for the semivining cultivars, primarily because of the ability of the semivining cultivars to compensate for the increased area/plant at smaller plant populations.