Growth, Phenophases, Growing Degree Days Requirement and Yield of Rice Cultivars under Semi-arid Tropics

Background: In India, several varieties are being developed by agricultural universities and research institutes which need to be tested for their suitability at a specific location. An experiment was conducted to identify rice cultivars suitable for Odisha and to know the effect of growing degree days at different phenophases on grain yield of rice under transplanted conditions. Methods: An experiment was conducted with fourteen cultivars during kharif season of 2023 having a duration of 120 to 150 days from sowing to harvest in randomized block design, replicated three times. The growing degree days (GDD) of rice calculated to understand the temperature requirement of the crop at different phenophases. Result: The cultivar CR Dhan 319 recorded significantly higher grain,straw and biological yield as compared to all other varieties. The GDD at vegetative stage ranged from 530 to 1204 Celsius, at reproductive stage 543 to 572Celsius and ripening stage 461 to 545 Celsius and the total GDD ranged between 1648 to2195Celsius. The GDD was higher at vegetative stage in long duration cultivars while it was higher at reproductive stage in short duration varieties. The cultivars 148 days duration recorded higher yield (4870 kg ha-1) beyond which there was decrease in yield and the crop receiving total GDD of 2060 from transplanting to harvesting recoded maximum yield (4860 kg ha-1). The optimum GDD at each phenophase found to be 120 at PI and young panicle stage, 245 at young panicle stage to reduction division, 178 at reduction division to anthesis, 113 at anthesis to ripening and 365 at ripening to maturity stages. This study is related SDG goals 1,2, 4 and 15 of United Nations.