Evaluation of the effects of limitations of source and sink on traits of soybean genotypes planted at different dates in Mazandaran

ABSTRACT: An experiment was conducted at the Agricultural Research Station of Baye–Kola in 2010 in the form of split- split using the randomized complete block design in order to evaluate the effects of imposing source – sink limitations on some traits of soybean genotypes as planted at different dates. The factors studied in this experiment included the planting date as the main factor, four soybean genotypes as the sub-factor, and five levels of source – sink limitations as the sub-sub factor. Results showed that the different soybean genotypes significantly differed in all the traits studied, except in the harvest index and the number of pods on the main stem, the effects of planting date were significant only on the length of the pods, the number of unfilled pods on the main and lateral shoots, and the harvest index. The effects of source – sink limitations were significant on the distance of the first pod from the soil surface, the seed yield, the number of unfilled pods on the lateral shoots, and the number of pods on the main stem and on the lateral shoots. According to the results we obtained, Line 033 had the highest seed yield, the largest number of nodes, the tallest plants, the greatest distance of the first pod from the soil surface, and the maximum pod length.