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In 1990, the effects of 6 planting dates, at 15 days intervals from 21 April to 4 July, and 2 plant spacings, 7 and 14 cm with in row, on agronomic characterisitics, yield,yield components and their vertical distribution on branches and nodes of the main stem of 3 green gram (Vigna radiata L.)cultivars, parto., Gohar , and VC 1973, were evaluated in the Research station,College of Agricultiure, Isfahan University of Technology, located at Lavark, Najaf-Abad.
Generally ,the effects of planting date on yield and all the other traits, specially yield components of the main stem was statistically significant. The number of days to different growth stages was fewer in realy planting dates, and increased due to short day-length in the delayed planting dates, and therefore,since increased in the late season planting dates, and therefore, since the yield components of the main stem were more important, the grain yield was increased.
plant densities had no significant effect on grain yield and growth stages. All the yield components were increased in low plant density. Therefore,grain yield per unit area was the same in both densities. Among the cultivars, VC 1973, because of having larger seeds, production of more poods and seeds on the main stem, and uniformity of seed maturity, had the highest yield ,and was recognized as the best cultivar for the region.
According to the yield prediction equation ,the genotypes with more vegetative dry matter production, high harvest index and test weight, longer and heavier main stem, and shorter period from sowing to 50% heading stage would have higher yields.Therefore ,it seems possible to use these traits as indirect selection criteria for grain yield . generally 60% of the pods and seeds were produced on middle third nodes of the main stem. Also the first 3 branches had the most number of pods and seeds, the largest seeds, and produced more than 50% of the yield.