Effect of leaf and flower removal on seed yield of lentil [Lens esculenta(L.)]

SUMMARY Field studies were carried out to determine the sources of photosynthate for developing pods and to assess the effect of defoliation and flower removal at different stages on the performance of lentil. The leaves of flowering nodes were the primary source of assimilate to pods. Removal of 25–75% of leaves reduced seed yield by varying degrees depending on crop growth stage. The plants compensated for the loss of foliage to some extent, possibly through increased efficiency of the remaining leaves. One complete or 50% defoliation reduced seed yield to different extents at the vegetative, flowering, early pod formation and late pod formation stages, the greatest effect being seen at flowering and early pod formation. Plants compensated considerably by production of new leaves when defoliated at the vegetative phase. Increased moisture supply greatly enhanced the compensation ability of the lentil plants. Removal of all flowers up to 1–2 weeks after an thesis under unirrigated conditions and up to 3 weeks after anthesis in irrigated conditions did not adversely affect the seed yield. Flower removal beyond this period resulted in a significant reduction in seed yield. Little seed yield was obtained when flower removal was continued for either 6 or 8 weeks under unirrigated conditions. The plants compensated for the loss of earlier-formed flowers by setting pods from later-formed flowers. Compensation was greatly enhanced when the crop was irrigated during the reproductive phase. There was relatively little or no effect of the deflowering treatments on the number of seeds per pod or weight per seed. The flowering period of the deflowered plants was extended and their senescence was delayed. When 25% of the flowers were removed at different intervals during the reproductive phase, seed yield was not adversely affected. An increased intensity of flower removal decreased yield but the decrease was not proportional to the degree of flower removal. The plants apparently compensated by setting new pods.