Division of Plant Physiology and Biochemistry, Indian Institute of Horticultural Research
A study on assessment of source-sink relationship was conducted by altering the source in okra cvs. Arka Anamika and Pusa Makhamali. Source was manipulated by defoliating at lower (1 to 4 nodes), middle (5 to 8 nodes), upper (ninth node upwards) and from all the nodes regularly during reproductive stage. Defoliation has considerably affected total dry-matter accumulation and its partitioning to developing fruits and seeds. In Arka Anamika, there was about 9–95% reduction in biological yield after partial or complete defoliation, while it was 11–82% in Pusa Makhamali. The effect on biological yield was minimum in plants where defoliation was effected on leaves of upper nodes (ninth node upwards). Cultivar variation was distinct in the pattern of dry-matter partitioning among fruit sinks at different positions on the plant. This variation in fruit dry-matter accumulation is attributed to a decrease in the partitioning of photoassimilates to the developing fruits after the source manipulation. The change in dry-matter partitioning resulted in reduction in seed dry matter at different positions and thus affecting the yield of seeding okra. The lower and middle node leaves are major source of photoassimilates for fruit development.
