Pollen fatty acid composition associated with heat tolerance of tropical rice

A nascent rice industry is expanding in Northern Australia. For this industry to be sustainable, it is critical that abiotic stressors are understood and managed. In particular, yield losses due to heat stress causing spikelet sterility will need to be managed through the development of heat tolerant rice varieties. Understanding the physiology of superior heat tolerant genotypes will be important in breeding efforts. Six selected rice genotypes grown under controlled environment growth cabinets under standard, transient and prolonged heat treatments were evaluated for spikelet sterility and fatty acid composition of the anthers. Nagina 22, was the only genotype that demonstrated heat tolerance across transient and prolonged heat stress, with low and moderate spikelet sterility, respectively. Other genotypes (Hayayuki, Teqing, Sasanishiki, Lemont and Moroberekan) showed severe spikelet sterility with prolonged heat stress. Nagina 22 also consistently showed significantly higher level of saturated and unsaturated fatty acids levels and concentration of 16 and 18 C fatty acids than the other genotypes. The fatty acid content and the composition of the anther tissue may be linked with heat tolerance, expressed as low spikelet sterility at higher temperature in rice.