High temperature stress and spikelet fertility in rice (Oryza sativa L.)

Abstract

In future climates, greater heat tolerance at anthesis will be required in rice. The effect of high temperature at anthesis on spikelet fertility was studied on IR64 (lowland indica) and Azucena (upland japonica) at 29.6 degrees C (control), 33.7 degrees C, and 36.2 degrees C tissue temperatures. The objectives of the study were to: (i) determine the effect of temperature on flowering pattern; (ii) examine the effect of time of day of spikelet anthesis relative to a high temperature episode on spikelet fertility; and (iii) study the interactions between duration of exposure and temperature on spikelet fertility. Plants were grown at 30/24 degrees C day/night temperature in a greenhouse and transferred to growth cabinets for the temperature treatments. Individual spikelets were marked with paint to relate fertility to the time of exposure to different temperatures and durations. In both genotypes the pattern of flowering was similar, and peak anthesis occurred between 10.30 h and 11.30 h at 29.2 degrees C, and about 45 min earlier at 36.2 degrees C. In IR64, high temperature increased the number of spikelets reaching anthesis, whereas in Azucena numbers were reduced. In both genotypes<or=1 h exposure to>or=33.7 degrees C at anthesis caused sterility. In IR64, there was no interaction between temperature and duration of exposure, and spikelet fertility was reduced by about 7% per degrees C>29.6 degrees C. In Azucena there was a significant interaction and spikelet fertility was reduced by 2.4% degrees Cd-1 above a threshold of 33 degrees C. Marking individual spikelets is an effective method to phenotype genotypes and lines for heat tolerance that removes any apparent tolerance due to temporal escape.

Climate Change and Population Growth in Timor Leste: Implications for Food Security

“…A drastic reduction in seed set at high temperatures has also been observed in rice. Jagadish et al (2007) observed that exposure of rice at peak anthesis to 34°C for 1 h at about 1100 h caused sterility, while exposure of rice spikelets to [35°C for 5 days at anthesis induced complete sterility (Satake and Yoshida 1978). In rice, genotypic variation in spikelet sterility at high temperature has been observed in a number of studies (Satake and Yoshida 1978;Matsui et al 2001;Prasad et al 2006), attributed to differences in the temperature threshold required to induce sterility (Nakagawa et al 2002).…”

“…In peanuts it was shown that genotypic variation in the optimum temperature for pollen germination varied from 25.5 to 35.0°C and for pollen tube growth from 30.5 to 36.8°C (Kakani et al 2002) suggesting that selection for high-temperature tolerance is feasible. Based on the observation that the floret is sensitive to high temperature at peak anthesis (Jagadish et al 2007), the parents used in mapping populations of rice have been screened for their sensitivity to high temperature (Jagadish et al 2007) for use in breeding of improved heat tolerance in rice. However, considerable further study needs to be conducted to determine the variation in acclimation to high temperatures and high temperature tolerance in crop species.…”

Spatial Assessment of Heat Stress Impact on Rice Production in Two Districts of Andhra Pradesh, India

“…They also found pollen viability is sensitive to high temperatures with lowland rice genotypes being more vulnerable than upland ones. Jagadish et al [6] found both upland and lowland rice spikelet sterility induced with less than 1 hr of exposure to an air temperature of at least 33.7°C and higher, based on a controlled environment experiment. Lowland indica rice exhibited a reduction in spikelet fertility by 7% per°C increase of temperature above 29.6°C whereas spikelet fertility was reduced by 2.4% per°C increase above 33°C for upland japonica rice [6].…”

“…Jagadish et al [6] found both upland and lowland rice spikelet sterility induced with less than 1 hr of exposure to an air temperature of at least 33.7°C and higher, based on a controlled environment experiment. Lowland indica rice exhibited a reduction in spikelet fertility by 7% per°C increase of temperature above 29.6°C whereas spikelet fertility was reduced by 2.4% per°C increase above 33°C for upland japonica rice [6]. In japonica rice, the critical temperatures to induce 50% sterility were estimated to be about from 36.5 to 38.5°C [2].…”

Field level evaluation of rice introgression lines for heat tolerance and validation of markers linked to spikelet fertility

“…The impact of heat stress on rice yield depends on the genotype, the growth stage at which heat stress is received and the period of the stress (Liao et al 2014;Poli et al 2013;Zhou et al 2012;Ye et al 2011;Jagadish et al 2010a;Prasad et al 2006;Morita et al 2005). In general, when rice plants are exposed to temperature greater than 35°C for more than one hour at anthesis, it results in increased sterility (Jagadish et al 2007). High temperature stress caused abnormal anther dehiscence and poor pollen germination which in turn increased spikelet sterility (Matsui and Omasa 2002;Jagadish et al 2010a).…”