Studies On Reproductive Abscission And Seed Yield Of Mungbean ( Vigna radiata ) In Sub-Humid Savanna Of Nigeria

A field study was conducted on the Research and Experimental Farm of the University of Agriculture Makurdi (7°41’N, 08°37’N, and 400 m above mean sea level), Nigeria, in 2001 and 2002 to examine the abscission of reproductive structures in mungbean ( Vigna radiata ). Four exotic cultivars (VC 2768A, VC 1178A, VC 2778A and VC 1973A) and a local cultivar (Ex–Zaria) were used for the study, which was laid out in a randomized complete block design and was replicated four times. Grain legumes generally undergo considerable abscission of their reproductive structures during flowering and fruiting stages. In this study the abscissions of flowers and pods differed widely among the cultivars. The abscissions of flowers and young pods varied from 14.4 to 36.8% and 12.3 to 38.5%, respectively. The number of flowers and harvestable pods per plant also varied from a high of 77.2 and 48.8 in VC 2768A to a low of 49.1 and 24.0 in VC 2778A, respectively. Conversely, young pods varied in number from 56.0 in VC 1973A to 38.9 in VC 2778A. In all the cultivars, more flowers occurred at the bottom of the canopy where abscission was also highest. The cultivar VC 2778A had highest (50.8) percent total abscission compared to the lowest of 29.1percent in VC 1973A. Seed yield ranged from 541.67 kg/ha in VC 2778A to 2000.2 kg/ha in VC 2768A. Seed weight and the number of seeds per pod, however, did not vary significantly. There was a high positive correlation (r = 0.94) between flowers and harvestable pods. Seed yield also correlated positively with the number of flowers, harvestable pods, seed weight and the number of seeds per pod. This study has shown that reproductive abscission exists in mungbean but it is of less intensity when compared to other legumes. The lower rate of abscission coupled with low incidences of pests and diseases and high nutritive value make the crop a dependable source of protein for resource-poor rural farmers in the tropics.