Identification of heat tolerant rice (Oryza sativa L.) genotypes under two environmental regimes

• Published in: Philippine Journal of Crop Science (Philippines) Vol. 34; no. 1
• Main Authors: Sierra, S.N, Laza, M.A., International Rice Research Inst. Los Baños, 4031 Laguna (Philippines), Manigbas, N.L., Philippine Rice Research Inst., Maligaya, Science City of Muñoz, 3119 Nueva Ecija (Philippines), Bartolome, V, Nora, L., International Rice Research Inst., Los Baños, 4031 Laguna (Philippines), Barroga, O.W.V, Noriel, J.M., Philippine Rice Research Inst., Maligaya, Science City of Muñoz, 3119 Nueva Ecija (Philippines), Redoña, E.D., International Rice Research Inst. Los Baños, 4031 Laguna (Philippines)
• Format: Journal Article
• Language: English
• Published: 01.05.2009
• Subjects: CROP PERFORMANCE; DESEMPENO DE CULTIVOS; DRY SEASON; ENVIRONMENT; ENVIRONNEMENT; ESTACION SECA; ESTRES TERMICO; FILIPINAS; GENOTIPOS; GENOTYPE; GENOTYPES; GRAIN; GRANOS; HEAT STRESS; HEAT TOLERANCE; http://www.fao.org/aos/agrovoc#c_11486; http://www.fao.org/aos/agrovoc#c_11488; http://www.fao.org/aos/agrovoc#c_2400; http://www.fao.org/aos/agrovoc#c_2593; http://www.fao.org/aos/agrovoc#c_3225; http://www.fao.org/aos/agrovoc#c_3346; http://www.fao.org/aos/agrovoc#c_35199; http://www.fao.org/aos/agrovoc#c_5438; http://www.fao.org/aos/agrovoc#c_5783; http://www.fao.org/aos/agrovoc#c_6070; http://www.fao.org/aos/agrovoc#c_6514; http://www.fao.org/aos/agrovoc#c_8488; INSTITUCIONES DE INVESTIGACION; INSTITUTION DE RECHERCHE; MEDIO AMBIENTE; ORYZA SATIVA; PERFORMANCE DE CULTURE; PHILIPPINES; POLEN; POLLEN; RENDEMENT; RENDIMIENTO; RESEARCH INSTITUTIONS; SAISON SECHE; STRESS THERMIQUE; TOLERANCE A LA CHALEUR; TOLERANCIA AL CALOR; YIELDS
• ISSN: 0115-463X

Rice (Oryza sativa L.) is sensitive to high temperature ( 35 deg C), especially during flowering, which results in spikelet sterility and reduced grain yield. With global warming, breeding rice varieties that can tolerate high temperature is needed. However, little is known about germplasm resources suitable for breeding heat tolerant rice varieties. The authors assessed the variability of 34 genotypes for heat-tolerance-related traits during the 2008 dry season at IRRI, Los Baños, Laguna and PhilRice, Muñoz, Nueva Ecija under heat-stressed and non-stressed trials. Significant differences were observed among the genotypes in the two environmental regimes. On the average, yield under heat stress was reduced by 79% to 16% relative to yield in non-stressed trials in PhilRice and IRRI, respectively. Grain sterilities at PhilRice and IRRI under heat stress were 30% and 15%, respectively, while being 18 and 14%, respectively, under non-stressed conditions in the two sites. Pollen sterilities under heat stress were 40% and 26% while being 31 and 27% under non-stressed conditions at PhilRice and IRRI, respectively. A negative correlation was observed between grain yield and pollen sterility (r=0.38*) and between grain yield and peak anthesis (r=037*) under heat stress at PhilRice. Performance of the genotypes were confirmed under controlled conditions during the 2009 DS. Pollen sterility ranged from 23 to 70%. Potential donors identified included IR22, IR2307-247-2-2-3, IR6, and Ganjay (76349). Diversity of the genotypes will be assayed further using SSR markers.