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Author: Singh, A. K. ×

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    ArticleItemOpen Access
    Determine Physiological Traits Associated with Flowering Stage Drought Tolerance in Lowland Rice (Oryza sativa L.) Genotypes
    (International Journal of Current Microbiology and Applied Sciences, 2017) Singh, A. K.
    Drought stress significantly reduced the RWC and LWP of the rice plant. Moreover, Azucena (DT check), NDR-359, NDR-97, DSU-18-6, Vandana, TN-1 and Moroberekan showed less depression. Result revealed that capacity to maintain high LWP is promising traits for selection to improve tolerance against flowering stage drought tolerance. Grain yield under water deficit at the flowering stage is negatively correlated with spikelet sterility and later associated with genotypic variation in maintenance of LWP. Correlation studies between RWC and per cent grain sterility and LWP vs. per cent sterility indicated that maintenance of RWC is necessary but not significant to ensure good yield. These result suggested that other feature are at least as important as RWC in determining response to flowering stage drought tolerance. Grain yield is well correlated with RL and RWD but strong regression coefficient was obtained between root length and RWC. This result indicated that root length did not contribute directly grain yield under drought at flowering stage. But, it indirectly helps to maintained higher plant water status. Assimilate accumulate prior to flowering are of permanent importance when plant experience drought stress at flowering stage. Present study indicated that translocation of soluble sugar for grain growth is supported by ACR and ATR was higher in stress. Grain yield was significantly correlated with ACR and ATR.
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    ArticleItemOpen Access
    GENETIC ARCHITECTURE, HETEROSIS AND INBREEDING DEPRESSION FOR YIELD AND YIELD ASSOCIATED PHYSIOLOGICAL TRAITS IN RICE (Oryza sativa L.) UNDER DROUGHT CONDITION
    (SAARC J. Agri, 2015) Singh, A. K.
    Simple and joint scaling tests led to similar inferences in respect of presence or absence of epistasis in majority of cases across the fourteen characters of six crosses in two conditions. The generation mean analysis revealed importance of additive (d) and/or dominance (h) gene effects as well as one or more of the epistatic gene interactions (i, j, l) for all the seven characters in most of the crosses under both the conditions. However, nature and magnitude of gene effects and epistatic interactions for a character exhibited considerable variation across the six crosses and two environmental conditions. Significance of dominance gene effects and epistatic interactions for most of the traits in six crosses under two conditions indicated that exploitation of heterosis through hybrid varieties appears to be a potential alternative. Only in drought condition, considerable number of crosses exhibited positive and significant estimates of standard heterosis across seven characters. Present study indicated apparent lack of desirable heterosis of requisite degree. It appears that extremely diverse nature of parents involved in six cross combinations may have resulted in incompatible gene combinations or genetic architecture in crosses resulting into poor performance and lack of heterosis for most of the characters. The positive and significant heterobeltiosis was noted for relative water content and membrane thermo stability in cross VI in irrigated condition.