EFFECT OF PRE-SOWING SEED TREATMENTS ON THE GROWTH AND YIELD OF BLACK GRAM (VIGNA-MUNGO [L])

Field experiments conducted in 2 seasons (pre-monsoon and late autumn) on presowing seed treatments of blackgram, the most important grain legume in India, revealed that soaking seeds in water, Na2HPO4, 6H2O (5 .times. 10-4 M), polyethylene glycol [PEG] (concentrations ranging from 10-2 to 10-4 M) and mixtures of PEG and Na2HPO4, 6H2O solutions for 4 h, and exposing seeds in partially saturated iodine vapor for 24 h, increased grain yield. This was mainly because of better utilization of stored soil moisture through enhancing the vigor of shoot and particularly root growth. Seed treatment with Na2HPO4 also appreciably increased the nitrogenase activity in root nodules. The best yield was obtained, particularly in Sept. sown crop which sustained its growth only on stored soil moisture, by treating seeds with mixtures of Na2HPO4 (5 .times. 10-4 M) + PEG (10-2 M) solutions; the increases in yield were 17% and 74% over the crops raised from untreated seeds for May and Sept. sown crops, respectively. The possible causes of such yield variations are discussed.