Development of Heat Tolerant Breeding Lines and Varieties in Rice

Rice cultivation is directly and significantly affected by climate change than other sectors of the economy.Agriculture is also a significant contributor to climate change and emission of nitrogenous oxide from rice field is one of the potent components causing global warming. Rice cultivation particularly in India is more affected by climate change and seasonal climate variability and its contribution is severe in yield reduction, crop failure and economic losses. The development of more sustainable, resilient agricultural systems could be achieved by identifying heat tolerant rice genotypes and development of new rice varieties for mitigating the yield losses under high temperature condition during summer and Kharif seasons. The chalky characteristic in rice grain is more prevalent with high temperatures that will bring quality and yield losses to rice growers. With a temperature rise of just 2 ºC is sufficient to trigger the trait, researchers have noted that a 4 ºC increase could ruin entire crop. The research focuses on identification of suitable rice genetic resources and development of heat tolerant rice varieties with high-quality grain and was carried out at Tamil Nadu Rice Research Institute, Aduthurai during 2007–08 and 2008–09. A total of 27 and 32 rice varieties from 7 countries, IRRI and WARDA were evaluated under International Rice Heat Tolerant Nursery (IRHTN, 2008 and 2009), the rice varieties viz., N22 and IDSA 77 were found to be high temperature tolerant. A total of 1669 F₄ breeding lines were screened for high temperature tolerance during June to September, 2009. A total of 154 breeding lines were advanced to F₅ generation and selection was carried out based on pollen sterility and spikelet sterility count (%), high-yielding potential with high grain quality above 35 ºC under field condition and 38 ºC under phytotron screening.