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Subject: Crop Physiology × Author: Konwar, Priti Bandana × End date: 2016 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    PHYSIOLOGICAL PERFORMANCE OF SOME SALI RICE GENOTYPES UNDER DELAYED DATES OF SOWING
    (2015) Konwar, Priti Bandana
    A study was conducted during the sali seasons of 2012 and 2013 at the experimental field of Instructional cum Research (ICR) farm, and at the Department of Crop physiology, Assam Agricultural University, Jorhat to assess the physiological performance of seven selected sali rice genotypes namely, Satya (G1), Luit (G2), Monoharsali (G3), Jaya (G4), Bordhan (G5), Basundhara (G6) and Srimanta (G7) under delayed dates of sowing. All agricultural practices were followed as recommended while raising the crop in the field. The experiments in the field were laid out in split plot design with three replications where five sowing dates were allocated the main plots and seven genotypes were allocated sub-plots. Uptake kinetics studies were carried out in the laboratory using Hoagland solution. Results obtained during the investigation revealed that delayed dates of sowing had significant influence on various morpho-physiological, biochemical and yield attributes. As compared to timely sowing, delayed sowing resulted in progressive reduction in the values of parameters namely leaf area index, leaf area duration, in-vivo leaf nitrate reductase activity, total leaf chlorophyll content ,chlorophyll stability index, starch content in culm, leaf soluble protein, rate of photosynthesis, plant biomass, accumulated nitrogen in above ground biomass , longest root length, root volume, days to panicle emergence and yield attributing traits. However, net assimilation rate showed an increase upto 27th July sowing and there after it decreased upto 10th August sowing. Root to shoot ratio, chlorophyll a to b ratio, proline content and chaffy grain percentage showed an increasing trend with deferred dates of sowing. While comparison was made between timely sowing and the deferred dates of sowing lowest reduction in the values of grain yield were recorded in genotype Manoharsali and Srimanta (G3 and G7) (35.66 % and 35.03 % under D2 ) , (42.89% and 58.57% under D3), (58.07% and 65.32 % under D4 ) and ( 78.07% and 77.73 % under D5). These two genotypes recorded better performance in terms of parameters like leaf area index, leaf area duration, total leaf chlorophyll content, proline content in leaf, starch content in culm, leaf soluble protein, photosynthetic rate, nitrogen accumulation in biomass and plant biomass etc. Uptake kinetic studies revealed that the genotype Basundhara (G6) and Srimanta (G7) showed lowest Km values and the latter genotype also showed highest accumulation of nitrogen in plant biomass. Plant biomass at physiological maturity stage and grain yield at harvest showed significant positive correlation with leaf area index, leaf area duration, starch content at dough stage and leaf soluble protein. The genotype Srimanta (G7) showed higher grain yield in timely sowing situation and its percent reduction with delayed dates of sowing was lowest. Therefore the genotype Srimanta (G7) can be regarded as better genotype for delayed sowing. The genotypes Satya (G1), Monoharsali (G3) and Srimanta (G7) were found to be superior in terms of nitrogen uptake efficiency; however, their physiological nitrogen utilization efficiency were lower as compared to other genotypes.