The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Kazuhiro Ohba - One of the best experts on this subject based on the ideXlab platform.
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impact of humidity on temperature induced grain sterility in rice oryza sativa l
Journal of Agronomy and Crop Science, 2008Co-Authors: W M W Weerakoon, A. Maruyama, Kazuhiro OhbaAbstract:High temperature-induced grain sterility in rice is becoming a serious problem in tropical rice-growing ecosystems. We studied the mechanism of high temperature-induced grain sterility of different rice (Oryza sativa L) cultivars at two relative humidity (RH) levels. Four varieties of Indica and Japonica rice were exposed to over 85 % RH and 60 % RH at 36/30 °C, 34/30 °C, 32/24 °C and 30/24 °C day/night air temperatures from late booting to maturity inside sunlit phytotrons. Increasing both air temperature and RH significantly increased Spikelet sterility while high temperature-induced sterility decreased significantly with decreasing RH. Neither Indica nor Japonica rice types were superior to the other in the response of their Spikelets to increased air temperature and RH. Increased Spikelet sterility was due to increased pollen grain sterility which reduced deposition of viable pollen grains on stigma. Reduction in sterility with decreased RH was more due to decreased Spikelet temperature than to air temperature. Thus the impact of RH should be considered when interpreting the effect of high temperature on grain sterility. Spikelet fertility was curvilinearly related to Spikelet temperature. Grain sterility increased when Spikelet temperature increased over 30 °C while it became completely sterile at 36 °C. The ability of a variety to decrease its Spikelet temperature with decreasing RH could be considered as avoidance while the variability in Spikelet sterility among varieties at a given Spikelet temperature could be considered as true tolerance.
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Impact of humidity on temperature-induced grain sterility in rice (Oryza sativa L)
Journal of Agronomy and Crop Science, 2008Co-Authors: W M W Weerakoon, A. Maruyama, Kazuhiro OhbaAbstract:High temperature-induced grain sterility in rice is becoming a serious problem in tropical rice-growing ecosystems. We studied the mechanism of high temperature-induced grain sterility of different rice (Oryza sativa L) cultivars at two relative humidity (RH) levels. Four varieties of Indica and Japonica rice were exposed to over 85 % RH and 60 % RH at 36/30 degrees C, 34/30 degrees C, 32/24 degrees C and 30/24 degrees C day/night air temperatures from late booting to maturity inside sunlit phytotrons. Increasing both air temperature and RH significantly increased Spikelet sterility while high temperature-induced sterility decreased significantly with decreasing RH. Neither Indica nor Japonica rice types were superior to the other in the response of their Spikelets to increased air temperature and RH. Increased Spikelet sterility was due to increased pollen grain sterility which reduced deposition of viable pollen grains on stigma. Reduction in sterility with decreased RH was more due to decreased Spikelet temperature than to air temperature. Thus the impact of RH should be considered when interpreting the effect of high temperature on grain sterility. Spikelet fertility was curvilinearly related to Spikelet temperature. Grain sterility increased when Spikelet temperature increased over 30 degrees C while it became completely sterile at 36 degrees C. The ability of a variety to decrease its Spikelet temperature with decreasing RH could be considered as avoidance while the variability in Spikelet sterility among varieties at a given Spikelet temperature could be considered as true tolerance.
P Q Craufurd - One of the best experts on this subject based on the ideXlab platform.
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Spikelet proteomic response to combined water deficit and heat stress in rice oryza sativa cv n22
Rice, 2011Co-Authors: S Krishna V Jagadish, Raveendran Muthurajan, Zhongwen W Rang, Richard Malo, Sigrid Heuer, J Bennett, P Q CraufurdAbstract:In future climates, rice crops will be frequently exposed to water deficit and heat stress at the most sensitive flowering stage, causing Spikelet sterility and yield losses. Water deficit alone and in combination with heat stress significantly reduced peduncle elongation, trapping 32% and 55% of Spikelets within the leaf sheath, respectively. Trapped Spikelets had lower Spikelet fertility (66% in control) than those exserted normally (>93%). Average weighted fertility of exserted Spikelets was lowest with heat stress (35%) but higher with combined stress (44%), suggesting acquired thermo-tolerance when preceded by water-deficit stress. Proteins favoring pollen germination, i.e., pollen allergens and beta expansin, were highly up-regulated with water deficit but were at normal levels under combined stress. The chaperonic heat shock transcripts and proteins were significantly up-regulated under combined stress compared with either heat or water deficit. The importance of Spikelet proteins responsive to water deficit and heat stress to critical physiological processes during flowering is discussed.
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high temperature stress and Spikelet fertility in rice oryza sativa l
Journal of Experimental Botany, 2007Co-Authors: S V K Jagadish, P Q Craufurd, T R WheelerAbstract: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 :511 h exposure to >= 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.
W M W Weerakoon - One of the best experts on this subject based on the ideXlab platform.
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impact of humidity on temperature induced grain sterility in rice oryza sativa l
Journal of Agronomy and Crop Science, 2008Co-Authors: W M W Weerakoon, A. Maruyama, Kazuhiro OhbaAbstract:High temperature-induced grain sterility in rice is becoming a serious problem in tropical rice-growing ecosystems. We studied the mechanism of high temperature-induced grain sterility of different rice (Oryza sativa L) cultivars at two relative humidity (RH) levels. Four varieties of Indica and Japonica rice were exposed to over 85 % RH and 60 % RH at 36/30 °C, 34/30 °C, 32/24 °C and 30/24 °C day/night air temperatures from late booting to maturity inside sunlit phytotrons. Increasing both air temperature and RH significantly increased Spikelet sterility while high temperature-induced sterility decreased significantly with decreasing RH. Neither Indica nor Japonica rice types were superior to the other in the response of their Spikelets to increased air temperature and RH. Increased Spikelet sterility was due to increased pollen grain sterility which reduced deposition of viable pollen grains on stigma. Reduction in sterility with decreased RH was more due to decreased Spikelet temperature than to air temperature. Thus the impact of RH should be considered when interpreting the effect of high temperature on grain sterility. Spikelet fertility was curvilinearly related to Spikelet temperature. Grain sterility increased when Spikelet temperature increased over 30 °C while it became completely sterile at 36 °C. The ability of a variety to decrease its Spikelet temperature with decreasing RH could be considered as avoidance while the variability in Spikelet sterility among varieties at a given Spikelet temperature could be considered as true tolerance.
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Impact of humidity on temperature-induced grain sterility in rice (Oryza sativa L)
Journal of Agronomy and Crop Science, 2008Co-Authors: W M W Weerakoon, A. Maruyama, Kazuhiro OhbaAbstract:High temperature-induced grain sterility in rice is becoming a serious problem in tropical rice-growing ecosystems. We studied the mechanism of high temperature-induced grain sterility of different rice (Oryza sativa L) cultivars at two relative humidity (RH) levels. Four varieties of Indica and Japonica rice were exposed to over 85 % RH and 60 % RH at 36/30 degrees C, 34/30 degrees C, 32/24 degrees C and 30/24 degrees C day/night air temperatures from late booting to maturity inside sunlit phytotrons. Increasing both air temperature and RH significantly increased Spikelet sterility while high temperature-induced sterility decreased significantly with decreasing RH. Neither Indica nor Japonica rice types were superior to the other in the response of their Spikelets to increased air temperature and RH. Increased Spikelet sterility was due to increased pollen grain sterility which reduced deposition of viable pollen grains on stigma. Reduction in sterility with decreased RH was more due to decreased Spikelet temperature than to air temperature. Thus the impact of RH should be considered when interpreting the effect of high temperature on grain sterility. Spikelet fertility was curvilinearly related to Spikelet temperature. Grain sterility increased when Spikelet temperature increased over 30 degrees C while it became completely sterile at 36 degrees C. The ability of a variety to decrease its Spikelet temperature with decreasing RH could be considered as avoidance while the variability in Spikelet sterility among varieties at a given Spikelet temperature could be considered as true tolerance.
Onoriode Coast - One of the best experts on this subject based on the ideXlab platform.
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high night temperature induces contrasting responses for Spikelet fertility Spikelet tissue temperature flowering characteristics and grain quality in rice
Functional Plant Biology, 2015Co-Authors: Onoriode Coast, R H Ellis, A J Murdoch, Cherryl Quinones, Krishna S V JagadishAbstract:Climate change is increasing night temperature (NT) more than day temperature (DT) in rice-growing areas. Effects of combinations of NT (24−35°C) from microsporogenesis to anthesis at one or more DT (30 or 35°C) at anthesis on rice Spikelet fertility, temperature within Spikelets, flowering pattern, grain weight per panicle, amylose content and gel consistency were investigated in contrasting rice cultivars under controlled environments. Cultivars differed in Spikelet fertility response to high NT, with higher fertility associated with cooler Spikelets (P 27°C was estimated to reduce grain weight. Generally, high NT was more damaging to grain weight and selected grain quality traits than high DT, with little or no interaction between them. The critical tolerance and escape traits identified, i.e. Spikelet cooling, relatively high Spikelet fertility, earlier start and peak time of anthesis and shorter Spikelet anthesis duration can aid plant breeding programs targeting resilience in warmer climates.
Zhenlin Wang - One of the best experts on this subject based on the ideXlab platform.
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plant density effect on grain number and weight of two winter wheat cultivars at different Spikelet and grain positions
PLOS ONE, 2016Co-Authors: Yong Li, Yingli Ni, Mengjing Zheng, Dongqing Yang, Jin Chen, Zhenlin WangAbstract:In winter wheat, grain development is asynchronous. The grain number and grain weight vary significantly at different Spikelet and grain positions among wheat cultivars grown at different plant densities. In this study, two winter wheat (Triticum aestivum L.) cultivars, ‘Wennong6’ and ‘Jimai20’, were grown under four different plant densities for two seasons, in order to study the effect of plant density on the grain number and grain weight at different Spikelet and grain positions. The results showed that the effects of Spikelet and grain positions on grain weight varied with the grain number of Spikelets. In both cultivars, the single-grain weight of the basal and middle two-grain Spikelets was higher at the 2nd grain position than that at the 1st grain position, while the opposite occurred in the top two-grain Spikelets. In the three-grain Spikelets, the distribution of the single-grain weight was different between cultivars. In the four-grain Spikelets of Wennong6, the single-grain weight was the highest at the 2nd grain position, followed by the 1st, 3rd, and 4th grain positions. Regardless of the Spikelet and grain positions, the single-grain weight was the highest at the 1st and 2nd grain positions and the lowest at the 3rd and 4th grain positions. Overall, plant density affected the yield by controlling the seed-setting characteristics of the tiller spike. Therefore, wheat yield can be increased by decreasing the sterile basal and top Spikelets and enhancing the grain weight at the 3rd and 4th grain positions, while maintaining it at the 1st and 2nd grain positions on the Spikelet.
