Influence of Micro Climatic Indices on Growth and Yield of Direct Seeded Upland Rice (Oryza sativa L.) Varieties in Assam.

Background: Rice (Oryza sativa L.) is the major cereal crop grown in India. Rice plays a pivotal role in the socio-cultural life of the people of Assam. The main objective of this study to investigate the influence micro climatic indices in relation to crop growth and yield of upland rice varieties with different dates of sowing in Assam. Methods: A field experiment was carried out at Instructional cum Research Farm, Assam Agricultural University, Jorhat during autumn season of 2017. The experiment consisted of four micro-climatic regimes (M) along with four different rice varieties (V). Result: The results of the experiment revealed that micro climatic indices viz., canopy temperature, growing degree days, soil moisture content, soil temperature, light intensity, depth of ground water table associated with 1st April sown crop recorded positive effect on growth and yield parameters in terms of plant height, leaf area index, number of filled grains per panicle, test weight, harvest index and grain yield (3004 kg/ha), followed by the micro-climate associated with 16th March sown crop. Among the varieties evaluated, CR-Dhan 203 recorded the highest grain yield of 2860 kg/ha and was significantly superior to that of other varieties except Inglongkiri. [ABSTRACT FROM AUTHOR]