Effect of planting date on qualitative characteristics and milling index of some rice cultivars in Amol, Iran

To investigate the effect of planting date on some quantitative and qualitative characteristics of rice cv. Binam, Tarom Mahali and Koohsar, a field experiment was conducted as factorial based on complete block design with three replications during three planting dates of 21 and 31 March, and 10 April in Deputy of the Rice Research Institute, Mazandaran Branch Amol, Iran. Three months after planting, 400 g of paddy sample for each plot was collected and evaluated to measure characteristics such as head and broken rice percentage, milling recovery, paddy hull and bran percentage, grain length before and after cooking, grain elongation ratio, milling degree, amylose percentage, gel concentration and gelatinization temperature. The effect of planting date and cultivar was significant on all characteristics in 1% probability level. The head rice percentage at first planting date and bran percentage, grain length after cooking, milling degree, gelatinization temperature, and grain elongation ratio at second planting date were better in Tarom Mahali cultivar. Grain length after cooking, grain elongation ratio and amylose percentage in Binam at the second planting date and bran percentage and grain length before cooking in Koohsar at the third planting date were better. The amount of broken rice percentage was lower at the first planting date in Binam and Koohsar cultivars compared with second and third planting dates. On the whole, transplanting at late April is recommended to get optimal quality of rice grains in this region