Study the effect of different sowing dates on qualitative and quantitative traits of soybean in Khuzestan region

In order to determine the best sowing date in two soybean cultivars, an experiment was done in Ramhormoz Agricultural Research Farm in split plots on the basis of randomized complete blocks design with three repetitions in 2017. Treatments includes three planting dates 1 August, 16 August, 1 September were placed in the main plots and two soybean varieties including 504 and Saland in subplots.Results showed that planting date had significant effect on plant height, number of pod per plant, number of seed per pod, number of seed per plant, number of plant per square meter, harvest index and seed protein percent. The effect of cultivar was significant on plant height, number of seed per pod, number of plant per square meter, total dry weight, biological yield and grain yield. Saland cultivar in the second planting date produced the highest 1000-grain weight with an average of 148.2 g and on the third planting date, the smallest one was obtained with an average of 103.8 g. Saland cultivar in the second sowing date had the highest grain yield (2059 kg. ha-1) and the highest biological yield (3305 kg. ha-1). In the third planting date, Saland cultivar yielded the lowest grain yield (506 kg. ha-1) and the lowest biological yield (954.3 kg. ha-1).Seed oil percentage was not significant in any of treatments, but in the third planting date it was less than two other planting dates. Seed protein percentage was affected by planting date and in the third planting date its reduction was significant.Thousand-grain weight had significant positive correlation with grain protein percentage at 1% probability level, which indicates that with increasing grain weight, more protein is stored in the grain.In general, it is possible to recommend Saland cultivar for sowing date in 16 August and 504 for sowing date in 1 August and 1September.