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Not AvailableRice grows mostly in tropical and subtropical regions, but it is very sensitive to higher temperature during reproductive stage especially flowering and anthesis. It is necessary to identify genetic donors for heat stress from high temperature rice growing environments. Temperature stress effects at reproductive stage by adopting three different planting dates with 15 days interval each in Environment-1(E1), Environment-2(E2) and Environment-3(E3) with forty three rice genotypes was studied. The temperature regimes were 35.6°C (E1) to 39.2°C (E3) at reproductive stage. From the results of AMMI analysis, the environment (E2) was found to be ideal for better identification of genotypes for heat tolerance with desirable traits. The elevated temperature at the time of flowering and maturity determines the yield per se of the genotypes. The hybrids adapted better than parental lines, showing the buffering nature and heterosis for stress tolerance. Under high temperature stress, the response of genotypes depended on developmental stage, but highest sensitivity was recorded at reproductive stage. The time of sowing, days to flowering (duration group), heat escape (early morning flowering) and inbuilt tolerance were the crucial factors in determining the performance of genotypes to varying temperature. Hence, it is necess ary to select genotypes by keeping in view the above factors for different temperature stress within and across the environment.Not Availabl

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Not AvailableRice is generally shows variable level of sensitivity to salinity during its developmental stages and remarkably sensitive during young seedling stage and early reproductive phase. Quantifying the level of salt tolerance based on salt stress indices is an effective method in identification of tolerant genotypes. In this study, the salt stress indices were used to identify best performing genotypes based on salt susceptibility indices (SSI) and salt response indices (SRI) as relevant parameters. Among the 39 genotypes studied, 29 showed better endurance to salt susceptibility indices, among them Pokkali, IR72132-AC-6-1 and IR70869-B-P-13-2 performed well with least SSI, which refers more tolerance with lesser yield reduction, whereas IR29 was vice-versa to the above. Genotypes IR72593-B-19-2-3-1, IR73104-B-1-1-3-2-1 and IR74802-3R-7-1-2 had a better performance with early flowering and highly responsive to salt stress with lower percent yield reduction. The phenotypic variation is higher than genotypic variation for all traits except for flowering duration and it indicates presence of variability for different traits. High heritability with variability, genetic advance and better salt stress indices indicates involvement of additive gene action and can be manipulated and utilized in further breeding program.Not Availabl

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Not AvailableRice grows mostlyICAR-Indian Institute of Rice Researc

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Not AvailableCombining ability and heterosis studies conducted in three different temperature stress regimes at reproductive stage by adopting three different planting dates in fifty seven hybrid rice parental lines and different hybrid combinations. The temperature regimes were 39.80 C to 27.50 C at reproductive stage. From the results of ANOVA and kempthroren line x tester analysis, few hybrid combinations were found to be ideal for better parental lines development for heat tolerance with desirable traits. The elevated temperature at the time of flowering and maturity determines the yield per se of the genotypes. The hybrids adapted better than parental lines, showing the buffering nature and heterosis for stress tolerance. Under high temperature stress, the response of genotypes depended on developmental stage, but highest sensitivity was recorded at reproductive stage. Flowering stage was very sensitive to high temperature which cause pollen sterility ultimately leads to spikelet sterility. In hybrid rice seed production practices, the pollen fertility plays major role for cross pollination. The time of sowing, days to flowering, temperature at flowering time, combing ability with different CMS lines and significant positive heterosis were the crucial factors in determining the performance of hybrids to varying temperature. Hence it is necessary to select parental lines and cross combinations to identify future better hybrids. By keeping in view the above factors for different temperature stress within and across the environment.Not Availabl

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Not AvailableTo assess the efficiency of different molecular markers which are linked to fertility restorer genes Rf3 and Rf4 of WA-CMS system, 103 breeding lines with no information on fertility restoration were screened with the help of molecular markers linked to major fertility genes Rf3 and Rf4. The breeding lines were crossed with APMS6A and the Pis were evaluated for pollen and spikelet fertility to identify restorers and maintainers. The SSR primer RM6100 linked to Rf4 gene of chromosome 10 and RM10313 linked to Rf3 gene of chromosome 1 showed eighty five and eight one percentage efficiency respectively in identifying restorer lines. Therefore, these markers are useful tool for evaluating large number of breeding lines to know about their fertility restoration in a short period of time without generating and evaluating large number of test crosses. The potential restorers may be identified with hundred percentage efficiency based on molecular screening itself, if candidate genes based markers are developed and validated for both Rf4 and Rf3 genes.ICAR-Indian Institute of Rice Researc

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Not AvailableCombining ability and heterosis studies conducted in three different temperature stress regimes at reproductive stage by adopting three different planting dates in fifty seven hybrid rice parental lines and different hybrid combinations. The temperature regimes were 39.8 deg C to 27.5 deg C at reproductive stage. From the results of ANOVA and kempthroren line x tester analysis, few hybrid combinations were found to be ideal for better parental lines development for heat tolerance with desirable traits. The elevated temperature at the time of flowering and maturity determines the yield perse of the genotypes. The hybrids adapted better than parental lines, showing the buffering nature and heterosis for stress tolerance. Under high temperature stress, the response of genotypes depended on developmental stage, but highest sensitivity was recorded at reproductive stage. Flowering stage was very sensitive to high temperature which cause pollen sterility ultimately leads to spikelet sterility. In hybrid rice seed production practices, the pollen fertility plays major role for cross pollination. The time of sowing, days to flowering, temperature at flowering time, combing ability with different CMS lines and significant positive heterosis were the crucial factors in determining the performance of hybrids to varying temperature. Hence it is necessary to select parental lines and cross combinations to identify future better hybrids. By keeping in view the above factors for different temperature stress within and across the environment.Not Availabl

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Not AvailableTo assess the efficiency of different molecular markers which are linked to fertility restorer genes Rf3 and Rf4 of WA-CMS system, 103 breeding lines with no information on fertility restoration were screened with the help of molecular markers linked to major fertility genes Rf3 and Rf4. The breeding lines were crossed with APMS6A and the F1s were evaluated for pollen and spikelet fertility to identify restorers and maintainers.The SSR primer RM6100 linked to Rf4 gene of chromosome 10 and RM10313 linked to Rf3 gene of chromosome 1 showed eighty five and eight one percentage efficiency respectively in identifying restorer lines. Therefore, these markers are useful tool for evaluating large number of breeding lines to know about their fertility restoration in a short period of time without generating and evaluating large number of test crosses.The potential restorers may be identified with hundred percentage efficiency based on molecular screening itself, if candidate genes based markers are developed and validated for both Rf4 and Rf3 genes.Not Availabl

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Not AvailableRice grows mostly in tropical and subtropical regions, but it’s very sensitive to higher temperature during reproductive stage especially flowering anthesis. It is necessary to identify genetic donors for heat stress from high temperature rice growing environments. Temperature stress effects at reproductive stage by adopting three different planting dates with 15 days interval each in Environment-1 (e1), Environment-2 (e2) and Environment-3 (E3) with forty-three rice genotypes was studied. The temperature regimes were 35.60C (E1) to 39.2 (E3) at reproductive stage. From the results of AMMI analysis, the environment (E2) was found to be ideal for better identification of genotypes for heat tolerance with desirable traits. The elevated temperature at the time of flowering and maturity determines the yield per se of the genotypes. The hybrids adapted better than parental lines, showing the buffering nature and heterosis for stress tolerance. Under high temperature stress, the response of genotypes depended on developmental stage, but highest sensitivity was recorded at reproductive stage. The time of sowing, days to flowering (duration group), heat escape (early morning flowering) and inbuilt tolerance were the crucial factors in determining the performance of genotypes to varying temperature. Hence, it is necessary to select genotypes by keeping in view the above factors for different temperature stress within and across the environment.Not Availabl

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Not AvailableIn rice WA (Wild Abortive) CMS system is commercially used for hybrid seed production. In WA-CMS fertility restoration is governed by two independent and dominant genes namely Rf4 and Rf3. Conventionally, the process of screening for the trait of fertility restoration is by tedious testcross progeny evaluation. In this study, earlier reported SSR markers RM6100 and RM 10313 linked to Rf4 and Rf3, respectively have been utilized to screen one hundred breeding lines and identified that 61 lines to carry both Rf3 and Rf4 genes and these lines can be utilized in hybrid rice breeding as restorers. A set of eighteen restorer lines with different combination of Rf4 and Rf3 were selected for crossing with five CMS lines viz., APMS6A, Pusa 5A, IR58025, IR68897, IR79156 and IR68888 and seventy test cross progenies were evaluated for their fertility restoration based on pollen and spikelet fertility. The hybrids viz., APMS6A X GQ-86, IR 79156A X IR-55778R, APMS 6A X VG-269 and IR 68888A X BR-827- 35 were observed to have more than 90% spikelet fertility. In this study observed that restoration ability varied with different CMS lines hence CMS lines also playing major role achieving higher heterosis.Not Availabl

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Not AvailableAn experiment was conducted at Indian Institute of Rice Research, Hyderabad, toassess the response of 34 hybrid rice parental lines to 120mM Nacl salt stress at germination stage. All the genotypes significantly responded to salt stress and most of the genotypes showed tolerance to threshold salt level and the results clearly depicted that germination stage is moderately tolerant to salinity. Root and shoot length of all cultivars were significantly affected by salt stress, The genotypes BK49-76, BK36-167, INDAM300-007, AjayaR, FL-478 and DRRH-2 manifested maximum tolerance where as genotypes BCW 56, IR 58025B, APMS6B showed susceptibility on par with IR28 at germination stage. The most of the genotypes were tolerant to salinity at seed germination which is an indicator for raising nursery in salt affected soils.Not Availabl