Title: Evaluation of nitrogen and planting date on heat tolerance rice cultivars in Khuzestan
Author: Abdolali Gilani
Abstract: This study planned to determine heat tolerance rice cultivars’ response to high temperature in growth duration by change nitrogen and planting date. The experiment was laid out in a randomized complete design on factorial-split with three factors and replications for two years (2017- 2018) in Shavoor agriculture research station. planting date as main plot included three levels (d1- 5/20, d2– 5/30 and d3- 6/9) and subplot were on factorial of rice cultivars namely (V1=IR64197-3B-15-2, ,V2=N22(ACC4819)+RAJBHOG V3=GHARIB(ACC32307+ GHARIB and V4-H0vazeh ) with three levels nitrogen ( n1-50,n2-75 and n3-100 kg/ha). The results of the combined analysis of variance showed a significant difference for grain yield, total dry matter, panicle number/ m2, seed per panicle, and %50 panicle exertion in %1 and 1000 grain weight in %5 level. The highest grain yield (3785 kg/ha) related to d3n2v1 treatment. The lowest and highest harvest index with 16/4 and 45/6 percentage obtained in d3n3v3 and d3n2v1 respectively. Panicle number/ m2 with 582 and 244 related to d1n2v1 and d3n2v2. The treatments of d3n3v3 and d1n1v2 with 126 and 39 had the highest and lowest grain per panicle.
Keywords: Rice lines, Dry bed seeding, Floret infertility, Yield loss, Yield components, Nitrogen nutrition.