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  • Author or Editor: S. C. Shankhdhar x
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A two-year field experiment was conducted to study the effect of three zinc levels 0, 20 kg ZnSO4 ha−1 and 20 kg ZnSO4 ha−1 + foliar spray of 0.5% ZnSO4 solution on plant height, leaf area, shoot biomass, photosynthetic rate and chlorophyll content in different wheat genotypes. Increasing zinc levels was found to be beneficial in improving growth and physiological aspects of genotypes. Soil application + foliar spray proved to be the best application in improving all the parameters. Zinc application brought about a maximum increment limit of 41.8% in plant height, 101.8% in leaf area, 86% in shoot biomass and 51.1% in photosynthetic rate irrespective of stages and year of study. A variation was found to occur among genotypes in showing responses towards zinc application and PBW 550 was found to be more responsive.

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Global warming is rising as a serious concern affecting agricultural production worldwide. Rice is a staple food crop and the threshold temperature for its pollination is 35 °C. A rise in temperature above this value can cause pollen sterility and may severely affect fertilization. Therefore, a study emphasizing the rise in temperature with respect to pollen viability was conducted with eleven rice genotypes during kharif seasons of 2010 and 2011 in indigenous field conditions. Increasing mean temperature by 12 °C at full flowering was found to severely affect the spikelet attributes of the crop. All genotypes showed spikelet sterility above 90% during both seasons. The study indicated that increased temperature may limit rice yield by affecting spikelet fertility and grain filling. The net reduction in grain yield was 30.4% and 27.6% in 2010 and 2011, respectively. A clear reduction in pollen size under high temperature was shown by scanning electron microscopy.

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Nitrogen use efficiency, more specifically physiological nitrogen use efficiency depends primarily on management of N, one of the major essential nutrients. It is required in increased agricultural production and may possibly cause soil toxicity if fed in excess. Rate of N fertilizer application in fertile agricultural field and improved productivity in sterile soils require the improvement of NUE. A field experiment was therefore conducted to evaluate the effect of different N levels (N0, N50, N100 and N200) on rice genotypes. Vegetative plant growth was found to be reduced under N0 while improved at N200 level. Among the genotypes, highest PNUE (34.94) and correspondingly higher yield (7.15 ton ha−1) was observed for Krishna Hamsa. The other traits viz. plant height, no. of productive tillers and LAI exhibited higher values for Krishna Hamsa as well. Hence these can be utilized as physiological markers for the selection of rice genotypes efficient in N use.

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