Fine mapping of rice drought QTL and study on combined effect of QTL for their physiological parameters under moisture stress condition

The present investigation was undertaken to study the effect of different yield QTL (DTY2.2, DTY3.1 and DTY8.1) under drought and their physiological response to drought stress. Backcross Inbred Lines (BILs) of IR64 (CB-193 and CB-229) along with IR64, APO and the traditional rice variety Norungan were raised in green house condition under water stress and control to evaluate the effect of the QTL on grain yield. The BIL CB-193 recorded higher photosynthetic rate (22.051), transpiration rate (7.152) and Ci/Ca ratio (0.597) whereas the BIL CB-229 recorded high relative water content (80.76%). It was found that the combination of three QTL (CB-229) performed better than the susceptible parent and the line with two QTL (CB-193 Fine-mapping of two QTLs viz., qDTY2.2 and qDTY8.1, for grain yield (GY) were conducted using backcross derived lines. Composite interval mapping analyses resolved the originally identified qDTY2.2 region of 6.7 cM into a segment of 2.1 cM and two sub QTLs at region between RM23132 and RM1578 (75.75 cM- 77.66 cM), RM515 and RM1578 (75.11 cM-77.66 cM) were identified in qDTY8.1 region. However this study provides a unique opportunity to breeders to introgress such regions together as a unit into high-yielding drought-susceptible varieties through MAS

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Not AvailableOrobanche, ‘the total root parasite’ known for more than a century, causes large losses in the agriculture production system in most countries of Asian, African and European continents. A large number of crops such as tomato, sunflower, tobacco, hemp, many legumes and crucifers are parasitized by Orobanche spp. The cultural practices and application of herbicide were the measures being adopted for control of this weed which is usually involves high cost. Control through resistance breeding is the most cost effective approach to eradicate the weed. To breed any cultivar against Orobanche, it is first important to understand the host and weed complex completely. Here in this review attempts have been made to review the life cycle of parasite, host weed interaction, resistance breeding strategies in few crops and thus coming out with future research perspective for developing host plants resistant to Orobanche. Keywords: Orobanche, resistance breeding, strigolactones, host-parasite interaction.Not Availabl

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Not AvailableOrobanche, ‘the total root parasite’ known for more than a century, causes large losses in the agriculture production system in most countries of Asian, African and European continents. A large number of crops such as tomato, sunflower, tobacco, hemp, many legumes and crucifers are parasitized by Orobanche spp. The cultural practices and application of herbicide were the measures being adopted for control of this weed which is usually involves high cost. Control through resistance breeding is the most cost effective approach to eradicate the weed. To breed any cultivar against Orobanche, it is first important to understand the host and weed complex completely. Here in this review attempts have been made to review the life cycle of parasite, host weed interaction, resistance breeding strategies in few crops and thus coming out with future research perspective for developing host plants resistant to Orobanche.Not Availabl

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Not AvailableOrobanche, ‘the total root parasite’ known for more than a century, causes large losses in the agriculture production system in most countries of Asian, African and European continents. A large number of crops such as tomato, sunflower, tobacco, hemp, many legumes and crucifers are parasitized by Orobanche spp. The cultural practices and application of herbicide were the measures being adopted for control of this weed which is usually involves high cost. Control through resistance breeding is the most cost effective approach to eradicate the weed. To breed any cultivar against Orobanche, it is first important to understand the host and weed complex completely. Here in this review attempts have been made to review the life cycle of parasite, host weed interaction, resistance breeding strategies in few crops and thus coming out with future research perspective for developing host plants resistant to Orobanche.Not Availabl

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Not AvailableICAR-CTRI, Rajahmundry, as a National Active Germplasm Site (NAGS) for tobacco germplasm, maintaining 138 burley tobacco germplasm. The morphological diversity present in this germplasm was investigated for estimating the existing variability for its further utilization. Out of 29 characters studied, the genotypes were found to be diverse for 26 traits and no variation observed for three traits viz., leaf type, inflorescence position and seed testa colour. Principal component analysis (PCA) with 26 diverse characters indicated that majority of the observed variation (91%) in the agromorphological traits found to be explained by eighteen PCA components. PCA1 alone explained 16% of the variation and was loaded mainly on eight traits viz., colour of leaf blade, leaf angle of insertion, inflorescence shape, leaf colour of midrib, width of leaf blade, plant shape, flower development of stamens and leaf length. The biplot of principal coordinates shows that the genotypes are scattered throughout the plot indicating the presence of morphological diversity among the entries. Clustering through unweighted pair groups produced grouping that defined four distinct clusters in 0 to 8 distance. The dissimilarity matrix worked out between 138 burley genotypes ranged from maximum value of 0.99 between YB-24 and Ky-171 to minimum value of 0.065 between Ky160 and Ky-171. The morphological diversity observed in the study indicates that the burley germplasm maintained at ICAR-CTRI is having sufficient diversity and can serve as a valuable source for burley genotype improvement.Not Availabl

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Not AvailableICAR-CTRI, Rajahmundry, as a National Active Germplasm Site (NAGS) for tobacco germplasm, maintaining 138 burley tobacco germplasm. The morphological diversity present in this germplasm was investigated for estimating the existing variability for its further utilization. Out of 29 characters studied, the genotypes were found to be diverse for 26 traits and no variation observed for three traits viz., leaf type, inflorescence position and seed testa colour. Principal component analysis (PCA) with 26 diverse characters indicated that majority of the observed variation (91%) in the agro-morphological traits found to be explained by eighteen PCA components. PCA1 alone explained 16% of the variation and was loaded mainly on eight traits viz., colour of leaf blade, leaf angle of insertion, inflorescence shape, leaf colour of mid-rib, width of leaf blade, plant shape, flower development of stamens and leaf length. The biplot of principal coordinates shows that the genotypes are scattered throughout the plot indicating the presence of morphological diversity among the entries. Clustering through unweighted pair groups produced grouping that defined four distinct clusters in 0 to 8 distance. The dissimilarity matrix worked out between 138 burley genotypes ranged from maximum value of 0.99 between YB-24 and Ky-171 to minimum value of 0.065 between Ky-160 and Ky-171. The morphological diversity observed in the study indicates that the burley germplasm maintained at ICAR-CTRI is having sufficient diversity and can serve as a valuable source for burley genotype improvement.Not Availabl

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Not AvailableAmong the abiotic stresses, drought is the major factor for heavy yield losses in rice production. The present study was undertaken with an aim of understanding the effect of mega QTLs of Apo controlling yield under drought. The BILs viz., CB 229 and CB 193-3 were evaluated for their drought responses under green house conditions along with the parents Apo, IR64 and check Norungan during Summer 2015, Kharif 2015, Rabi 2015-16. The results from this study reported that, Apo and BILs had higher photosynthetic rate when compared to IR64 under drought. CB 229 had low reduction per cent of photosynthesis (45.25%), Ci/Ca (23.88%), conductance (52.38%) and RWC (25.72%) compared to susceptible parent IR64. Number of filled grains was much higher in Apo, CB229 and CB 193-3 when compared to IR64 under stress condition. The significant reduction in single plant yield under moisture stress condition was observed in all the genotypes especially in IR64 (65.15%). Reduction was relatively less in the donor Apo and BILs. CB 229 showed a greater RWC, conductance, moderate transpiration rate, increased water uptake, a higher assimilation rate and a higher grain yield under the moisture stress condition compared to the other BIL and IR64. It was found that CB 229 with three QTL, i.e., qDTY2.2, qDTY3.1 and qDTY8.1, showed better performance than CB 193-3 with two QTL, qDTY3.1 and qDTY8.1, under severe stress while in irrigated condition CB 229 was onpar with IR64.Not Availabl

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Not AvailableThe present investigation was undertaken to study the effect of different yield QTL (DTY2.2, DTY3.1 and DTY8.1) under drought and their physiological response to drought stress. Backcross Inbred Lines (BILs) of IR64 (CB -193 and CB-229) along with IR64, APO and the traditional rice variety Norungan were raised in green house condition under water stress and control to evaluate the effect of the QTL on grain yield. The BIL CB-193 recorded higher photosynthetic rate (22.051), transpiration rate (7.152) and Ci/Ca ratio (0.597) whereas the BIL CB-229 recorded high relative water content (80.76%). It was found that the combination of three QTL (CB-229) performed better than the susceptible parent and the line with two QTL (CB-193 Fine-mapping of two QTLs viz., qDTY2.2 and qDTY8.1), for grain yield (GY) were conducted using backcross derived lines. Composite interval mapping analyses resolved the originally identified qDTY2.2 region of 6.7 cM into a segment of 2.1 cM and two sub QTLs at region between RM23132 and RM1578 (75.75 cM- 77.66 cM), RM515 and RM1578 (75.11 cM-77.66 cM) were identified in qDTY8.1 region. However this study provides a unique opportunity to breeders to introgress such regions together as a unit into high-yielding drought-susceptible varieties through MAS.Not Availabl

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Not AvailableIn this study, four Backcross Inbred lines (BIL) with multiple QTL combinations ( and were studied qDTY , qDTY qDTY ) 2.2 3.1 8.1 to estimate their yielding ability and stability of yield gain as an effect of introgressed drought yieldQTL under moisture stress. The four BIL lines namelyCB-193-1 ( and ), CB-193-2 ( and ), CB-193-3 ( and qDTY qDTY qDTY qDTY qDTY 2.2 3.1 2.2 8.1 3.1 qDTY qDTY , qDTY qDTY 8.1 2.2 3.1 8.1 ) and CB- 229 ( and ) were observed for biometrical traits related to yield and physiological parameters under moisture stress. The results showed that the line CB-229 outperformed others under drought, which indicated that, the combination of three QTLs viz., and had a major effect on grain yield under qDTY , qDTY qDTY 2.2 3.1 8.1 moisture stress than single and 2-QTL lines. Graphical genotyping was carried out using polymorphic SSR markers on these lines and found that they were harbouring many chromosomal segments from Apo, the donor and the maximum recovery of IR64 was found in linkage group 2 and 6. The total protein content, osmotic adjustment and the chlorophyll 'a' were also found to be higher in these lines which conferred tolerance to drought stress. The slow reduction in RWC with higher photosynthetic rate and conductance were found in these lines as of the donor parentApo.Not Availabl

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Not AvailableOne of priority research area in rice is identification of suitable genotypes for rain fed condition. Quantifying the drought tolerance genotypes was done with different stress indices obtained from the yield data under severe drought and irrigated condition with four backcross inbred lines derived from the cross between IR64 (drought susceptible) and Apo (drought tolerant) which carried three mega QTL in different combination of classes namely qDTY2.2, qDTY3.1 and qDTY8.1. The genotype CB 229 is the highly tolerant one confirmed by tolerant and susceptible indices, which had three DTY QTL (qDTY2.2, qDTY3.1 and qDTY8.1) combinations maximizes the yield in drought condition. Among the selection indices, YI, MPI, DRI, STI, HM, GMP, MRP and RE are the best indices to identify tolerant genotype. Clustering based on principal component analysis exhibits that CB 229, CB 193-2 and CB 193-3 falls on the quarter where tolerant indices found. Overall study shows that the selection based on stress indices may be rewarded to identify superior genotypes under severe drought condition.Not Availabl