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Not AvailableThe study pertains to a series of training programs organized by ICAR-Indian Institute of Rice Research (ICAR-IIRR) under the TSP project for tribal farmers of Khammam District induring 2014-15. The rice technology package was demonstrated to the selected farmers with Improved Sambamahsuri (ISM) - a Bacterial Leaf Blight resistant variety, quality seed production, information on parthenium control measures and skill training on preparation of compost from parthenium. The objectives of the study were to assess the economics of rice production practices and quantify yield gaps and to provide rice intervention package to the selected tribal farmers and to elicit information on constraints in rice production and suggestions from women farmers to improve the effectiveness of training.It can be concluded that the average yield of Rice Interventions (RI) and the average yield of the Farmers Practice (FP) differ significantly in case of tribal farmers’ fields. The Rice Interventions had a yield advantage of 1.85 t ha-1, which could be attributed to the rice variety, improved Samba mahsuri, training on the package of practices and seed production and parthenium composting. There exists a yield gap of 27 per cent which, if shortened, will result in increase in production. Hence, efforts should be made to disseminate the improved rice varieties and information on good management practices.Not Availabl

Effect of salinity and use of stress indices of morphological and physiological traits at the seedling stage in rice

843-850Rice (Oryza sativa L.) is the most important cereal crop and a major staple food for majority of the human populations worldwide. Rice crop is sensitive to salinity. In spite of large number of studies on salinity tolerance of rice, our knowledge on the overall effect of salinity on rice seedling growth is limited. Improvement in salt tolerance of crop plants remains indescribable, largely due to the fact that salinity is a complex trait which affects almost every aspect of the physiology, biochemistry and genomics of plants. The present investigation was conducted to establish the relationship between various morphological, physiological traits and stress indices. A set of 131 rice accessions was evaluated in two levels namely, non-stress (EC ~ 1.2 dS/m) and saline stress (EC ~ 10 dS/m) in hydroponics at seedling stage. Root length and shoot lengths were reduced by 52 and 50%, respectively in saline stress compared to non-stress conditions. There was a significant correlation between various morphological and physiological parameters in non-saline in addition to saline stress as well as non-stress. The effect of the increased Na+ concentration in the medium is detrimental to root length and shoot length as observed by reduction in root length and a concomitant reduction in shoot length. Increased concentration of Na+ led to augmented Na+/K+ ratio with increased stress in the medium and decreased expression of traits. A significant positive correlation (r=0.60) was noticed between stress tolerance index (STI) of root and shoot length. The stress susceptibility index (SSI) for root length was expressed significant positive correlation with SSI for shoot length (r=0.43). SSI for K+ content was registered significant negative correlation with STI for Na+ content (r=-0.43). The three accessions namely, IC 545004, IC 545486 and IC 545215 were found to be the best performers adjudged on the morphological and physiological criteria in saline stress situation. These three rice accessions could be used as a donor parent or for genotypic studies in future breeding programs

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Not AvailableWith increasing population size, there is an urgent need to double the global food production by 2050, and the onus is on the agricultural scientists to develop new technologies and varieties to double the production. Development of new varieties in any crop varieties is time-consuming as it is dependent on generation period of a crop. Speed breeding or accelerated plant breeding is an emerging strategy among plant breeders to develop new cultivars in short span of time. Here, the plants are grown in controlled growth chambers or greenhouses using optimal light intensity and quality, particular day length and temperature, which accelerates various physiological processes in plants especially photosynthesis and flowering, thus shortening the generation time. Speed breeding can be used to achieve up to 4–6 generations per year instead of 2–3 generations under normal glasshouse conditions. Speed breeding approaches and protocols are well established and standardized for major crop species like wheat, barley and canola. This strategy is now being applied, and standardization protocols are in progress for other crops including perennial fruit crop like apple. Speed breeding could serve as a basic platform for integrating high-throughput phenotyping and genotyping techniques, marker-assisted/genomic selections and gene editing for improvement of the traits in crop species. The present chapter gives an overlook of speed breeding activities carried out in different crops and its importance in present situation of crop improvement under vagaries of environment due to climate change.Not Availabl

Effect of salinity and use of stress indices of morphological and physiological traits at the seedling stage in rice

Not AvailableRice (Oryza sativa L.) is the most important cereal crop and a major staple food for majority of the human populations worldwide. Rice crop is sensitive to salinity. In spite of large number of studies on salinity tolerance of rice, our knowledge on the overall effect of salinity on rice seedling growth is limited. Improvement in salt tolerance of crop plants remains indescribable, largely due to the fact that salinity is a complex trait which affects almost every aspect of the physiology, biochemistry and genomics of plants. The present investigation was conducted to establish the relationship between various morphological, physiological traits and stress indices. A set of 131 rice accessions was evaluated in two levels namely, non- stress (EC ~ 1.2 dS/m) and saline stress (EC ~ 10 dS/m) in hydroponics at seedling stage. Root length and shoot lengths were reduced by 52 and 50%, respectively in saline stress compared to non-stress conditions. There was a significant correlation between various morphological and physiological parameters in non-saline in addition to saline stress as well as non-stress. The effect of the increased Na concentration in the medium is detrimental to root length and shoot length as observed by reduction in root length and a concomitant reduction in shoot length. Increased concentration of Na led to augmented Na /K ratio with increased stress in the medium and decreased expression of traits. A significant positive correlation (r=0.60) was noticed between stress tolerance index (STI) of root and shoot length. The stress susceptibility index (SSI) for root length was expressed significant positive correlation with SSI for shoot length (r=0.43). SSI for K content was registered significant negative correlation with STI for Na content (r=-0.43). The three accessions namely, IC 545004, IC 545486 and IC 545215 were found to be the best performers adjudged on the morphological and physiological criteria in saline stress situation. These three rice accessions could be used as a donor parent or for genotypic studies in future breeding programs.Not Availabl

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Not AvailableTo improve grain yield under direct seeded and aerobic conditions, weed competitive ability of a rice genotype is a key desirable trait. Hence, understanding and dissecting weed competitive associated traits at both morphological and molecular level is important in developing weed competitive varieties. In the present investigation, the QTLs associated with weed competitive traits were identifed in BC1F2:3 population derived from weed competitive accession of O. glaberrima (IRGC105187) and O. sativa cultivar IR64. The mapping population consisting of 144 segregating lines were phenotyped for 33 weed competitive associated traits under direct seeded condition. Genetic analysis of weed competitive traits carried out in BC1F2:3 population showed signifcant variation for the weed competitive traits and predominance of additive gene action. The population was genotyped with 81 genome wide SSR markers and a linkage map covering 1423 cM was constructed. Composite interval mapping analysis identifed 72 QTLs linked to 33 weed competitive traits which were spread on the 11 chromosomes. Among 72 QTLs, 59 were found to be major QTLs (> 10% PVE). Of the 59 major QTLs, 38 had favourable allele contributed from the O. glaberrima parent. We also observed nine QTL hotspots for weed competitive traits (qWCA2a, qWCA2b, qWCA2c, qWCA3, qWCA5, qWCA7, qWCA8, qWCA9, and qWCA10) wherein several QTLs co-localised. Our study demonstrates O. glaberrima species as potential source for improvement for weed competitive traits in rice and identifed QTLs hotspots associated with weed competitive traits.Department of Biotechnology, Government of India Grant no. BT/PR17115/NER/95/434/2015