Please use this identifier to cite or link to this item: http://prr.hec.gov.pk/jspui/handle/123456789/2452
Title: PHYSIOLOGICAL STRATEGIES TO IMPROVE STAND ESTABLISHMENT AND YIELD OF SPRING MAIZE UNDER EARLY AND LATE SOWN CONDITIONS
Authors: AHMAD, IJAZ
Keywords: Applied Sciences
Agriculture & related technologies
Agronomy
Issue Date: 2011
Publisher: UNIVERSITY OF AGRICULTURE, FAISALABAD PAKISTAN
Abstract: Although the yield potential of spring maize is much higher than autumn maize, high temperature at reproductive stage is one of the main problems in spring especially in late sown conditions. Early sowing of the crop seems an ideal solution to escape the crop from heat spell but low temperature causes poor emergence and seedling establishment. Under these temperature extremes, osmotic and oxidative stresses are major reasons of crop damage. Exogenous application of various physiological strategies like antioxidants, osmoprotectants and plant hormones may lessen the damage. Initially in first two experiments, three levels of ascorbic acid, salicylic acid and hydrogen peroxide (0, 20 and 40 mg L-1) were optimized as seed priming or foliar application strategies under net house condition using single maize hybrid (Hi Swan-9697). The optimization was done on the basis of emergence and seedling vigor in priming experiment, 20 mg L-1 was selected as an optimized level all these compounds as an effective priming strategy. Seed primed with AsA, SA and H2O2 resulted in faster emergence, better, more and uniform stands. Seed priming with AsA, SA and H2O2 improved seedling vigor by increasing leaf Chl, nutrient content and better defense system with stimulating activities of SOD, CAT and POD in seedling. Foliar application of AsA, SA and H2O2 improved seedling vigor by increasing chlorophyll, nutrient contents and improving antioxidant defense system. Both levels of solutions of foliarly applied AsA, SA and H2O2 are equally effective for improving seedling vigor so the lower level of (20 mg L-1) was selected. The field experiment was conducted to explore the role of AsA, SA and H2O2 as seed priming agent and foliar application at three sowing dates i.e early (1st February), optimum (22nd February) and late (15th March). Different priming treatment enhanced rapid emergence but both priming and foliar application strategies caused earlier tasselling, silking and physiological maturity at each sowing dates. Improving antioxidants and nutrient homeostasis enhanced chlorophyll which improved growth and development under early and late stress conditions. It is suggested that all physiological strategies increased grain yield associated with improvement in number of grain and size of grain at each sowing dates by improved antioxidants defense system and nutrient homeostasis which reduce oxidative damages and improving stress tolerance under late sown condition of spring maize.
URI:  http://prr.hec.gov.pk/jspui/handle/123456789//2452
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