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Twenty-four promising drought tolerant genotypes of IRRI and different parts of India were evaluated for genetic variability and drought susceptibility index (DSI) for 12 quality characters and grain yield under irrigated (E1) and drought (E2) conditions. In the present study differences among the genotypes are highly significant for all the characters; between the environments head rice recovery, alkali spreading value, water uptake, kernel length after cooking and yield were significant, while genotype × environment interaction was only significant for hulling, milling, head rice recovery and water uptake. Head rice recovery, alkali spreading value, water uptake and amylose content were observed to be governed by additive gene action under both the environments. Grain yield was positively correlated with kernel width and amylose content under stress environment while, kernel width was positively correlated with hulling and milling and kernel length was correlated with amylose content. The path coefficient analysis revealed that only kernel width in both the environments and amylose content in E2 had positive direct effect on yield. Most of the genotypes expressed low DSI value (<1) for yield and quality characters. However, Swarna and IR 78877-181-B-1-2 were identified as stable genotypes with low DSI value for seed yield and quality characters.

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The aim of this study was to determine the susceptibility to drought of selected genotypes of pea and yellow lupine. An analysis was made of the changes in protein and phenolics content and how they affect the yield parameters. The plant material consisted of six genotypes of pea and yellow lupine. Seedlings (plants with 5–6 leaves) were subjected to drought at 25% field water capacity for 2 weeks. Soil drought decreased the relative water content (RWC) in the leaves of pea and lupine. On the 14th day of drought the increase in protein content was almost two-folds higher in lupine plants than in pea. The phenolics content showed an increase in both pea and lupine plants on the 1st day of drought (20% and 15%, respectively), while on the 14th day the phenolics content decreased by 2% in pea, and was not significantly different in lupine. Soil drought reduced the values of almost all yield components. Only the 1000-seed weight increased under drought conditions. Based on the drought susceptibility index values for RWC, protein and phenolics content, seed yield and biomass, the least drought-susceptible genotypes were Batuta (pea) and Morocco 4 (lupine), as they had the lowest values of these parameters.

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Thirty diverse elite Indian wheat genotypes varying in their yield performance and drought tolerance were evaluated to examine differences for some drought tolerance characters and to determine relationship between these characters. Genotypes differed in their response for grain yield, days to heading, excised-leaf water loss and relative water content under both conditions over years. Under irrigated conditions differences in the genotypes for water retention traits were not clear. The varieties HPW251, Hindi 62, HPW184, VL 892 and VL 907 showed a good combination of drought resistance, water retention and high grain yield, whereas C 306, VL 421 and NI 5439 had high grain yield only under drought stress conditions and showed better water retention in the leaves. These genotypes may be used for exploitation of drought tolerance in wheat breeding programmes. Drought response index (DRI) appeared to be an important trait as the genotypes having high DRI values also had high grain yield, high water retention and low score of drought susceptibility index (DSI) under drought stress.

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The relative efficiency of in vitro and in vivo screening techniques for drought tolerance, comprising various parameters, namely germination (%), shoot length, root length, coleoptile length, root number, root/shoot ratio and seedling vigour index (SVI) under in vitro conditions and morpho-physiological and yield-contributing traits under in vivo conditions, was studied using 78 winter × spring wheat-derived doubled haploid lines of bread wheat along with 13 parental genotypes and two check varieties, HPW 155 and PBW 343. Analysis of variance for different in vitro parameters in control (0 MPa) and stress (−0.7 MPa) environments and various in vivo parameters under irrigated and rainfed environments indicated sufficient genetic variability and the differential response of the genotypes to the different stress levels for all the in vitro and in vivo parameters. Correlation studies revealed the significance of percentage germination, root number, coleoptile length and seedling vigour index under in vitro conditions and relative water content and excised leaf water loss under in vivo conditions as important selection criteria for drought tolerance, as these parameters were related with each other as well as with the drought susceptibility index (S). The significant positive rank correlation between the in vitro (−0.7 MPa) and in vivo (rainfed) stress conditions indicated that the performance of a genotype under field conditions is very similar to its performance under laboratory conditions. Hence, the selection precision for a crucial and complex trait like drought tolerance in wheat can be enhanced by exercising in vitro selection coupled with evaluation in the field. The drought susceptibility index ‘S’ should not be taken as the sole criterion to categorize genotypes as drought-tolerant or susceptible ones.

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In order to locate QTLs controlling the phenotypic stability and drought tolerance of yield and yield components in barley, seven disomic addition lines were sown together with their parents (donor and recipient) in a randomized complete block design with three replications under four rainfed and irrigated conditions. The descriptive diagram of yield and yield components exhibited a genotype (G) × environment (E) interaction and moderate variability over different environments, indicating the possibility of selection for stable and drought-tolerant entries. The AMMI stability value (ASV) and yield stability index (YSI) discriminated addition lines 2H and 4H as the most stable and droughttolerant.Path analysis revealed that the relative contribution of the number of seeds per plant (NSPP) (0.71) to grain yield (GY) was higher than that of the number of seeds per spike (SPS) (−0.44) and of thousand-seed weight (TSW) (−0.14). Therefore, the contribution of NSPP to the stability of GY over different environments was higher than that of other yield components. In other words, the instability of GY was caused by TSW and SPS in different environments. Path analysis on the drought susceptibility index revealed that most of the QTLs controlling drought tolerance and drought susceptibility in barley are located on chromosomes 3H and 6H, respectively.

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Drought tolerant maize (Zea mays L.) hybrids are crucial to sustainability of maize production in West and Central Africa (WCA). Two studies were conducted at three locations in Nigeria for 2 yr to (i) assess performance of 156 early-maturing maize inbreds and three hybrid types and (ii) determine heterosis among the lines and relationship between lines per se and hybrid performance. The inbreds and their hybrids were evaluated separately under drought and well-watered conditions. Genotype, environment and genotype × environment interactions were significant for grain yield under the research conditions. Grain yield of inbreds ranged from 0.06 t ha−1 for TZEI 123 to 1.92 t ha−1 for TZEI 17 under drought. While differences in grain yield among hybrid types (single, three-way and double-cross hybrids) were not significant under drought, significant differences were detected among hybrid types under optimal conditions. GGE biplot analysis identified three inbreds, TZEI 18, TZEI 56, and TZEI 1 and hybrids TZEI 129 × TZEI 16, (TZEI 17 × TZEI 16) × TZEI 157 and (TZEI 16 × TZEI 157) × TZEI 129 as ideal across research conditions. Midparent heterosis (MPH) and high-parent heterosis (HPH) for grain yield were higher in the well-watered conditions than under drought. Positive and significant correlations existed between MPH, HPH and yield under both research conditions. Drought tolerant hybrids with stable and high yield are available for promotion for adoption by farmers in WCA.

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Villegas, D., Garcia del Moral, L. F., Rharrabti, Y., Martos, V., Royo, C. (2007): Morphological traits above the flag leaf node as indicators of drought susceptibility index in durum wheat. J. Agron. Crop Sci. , 193 , 103

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248 Villegas, D., Garcýa del Moral, L.F., Rharrabti, Y., Martos, V., Royo, C. 2007. Morphological traits above the flag leaf node as indicators of drought susceptibility index in durum wheat

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