Genotype by Environment Interaction in Rice Under High Temperature Stress Condition in Cagayan

Abstract

Twelve rice genotypes were planted in four municipalities of Cagayan (Iguig, Peñablanca, Solana, and Tuguegarao). It aimed to assess genotype by environment interaction (GEI) of rice cultivated by farmers in Cagayan as well as their stability. This study was also designed to identify genotypes suited to high temperature-prone areas and the most discriminating environment to screen genotypes for high temperature tolerance. During anthesis, the recorded maximum temperature ranged from 33.6-42.4°C in Iguig, 32.9-44.80C in Peñablanca, 32.1-40.5°C in Solana, and 32.6-41.1°C in Tuguegarao. Panicle and canopy temperature were lower than air temperature in Iguig and Peñablanca but higher in Solana and Tuguegarao. Variance due to genotype, environment and GEI were found significant (p≤0.05) for yield. Environment contributed the greatest proportion to yield which was 43.1% of the total variance, while genotype contributed 35.5%, and GEI 21.5%. Spikelet fertility, panicle length, number of grains per panicle, and grain weight were not significantly affected by GEI. However, panicle length and spikelet fertility were significantly affected by genotype and environment, while number of grains per panicle and grain weight were significantly affected only by environment. NSIC Rc 152, Rc 218, Rc 222, PR40330, and PR42026 were found high-yielding with wide adaptation to high temperature conditions. NSIC Rc 152 and PR40330 were the most outstanding genotypes. These genotypes can be used as parents for development of new heat-tolerant lines. Iguig was the best location for screening and selecting generally adapted genotypes under high temperature condition.