Please use this identifier to cite or link to this item:
Keywords: Applied Sciences
Agriculture & related technologies
Garden crops(Horticulture)
Issue Date: 2016
Abstract: Lady’s finger or Okra is a member of family malvacae. It is multipurpose crop; its fibrous tender fruits called pods are used as vegetable; seeds, stem and roots used for industrials purposes. In past it was considered as minor crop and no care was taken for its improvement at national and international level in research programs. It grows well at temperature ranges of 18 to 35oC and gives highest yield. Heat and drought events will be intensified due change in climate, activating modifications in the ecosystem and failure or low productivity of crops which are prone to abiotic stresses and same case is with okra. Major constraint which affects vegetative and reproductive phase of okra is heat stress. Heat stress damage quality as well as yield of okra. The research was conducted with the aim to screen out genetically diverse and improved germplasm while eradicating physiological and genetic basis of better adaptation under thermal stress and enhancement of heat tolerance by foliar application of proline. In first experiment comparative performance of one hundred okra genotypes was investigated under heat stress condition. For this purpose one hundred (100) okra genotypes were grown under control environmental conditions of high temperature 45/35°C (day/night). Data for morphological attributes (root length, shoot length, shoot and root fresh weight, number of leaves and root and shoot dry weight) and physiological attributes (transpiration rate, stomatal conductance to water, photosynthetic rate, leaf surface temperature, chlorophyll contents, sub-stomatal CO2 and water use efficiency) was recorded. According to recorded data genotypes were classified on the basis of their performance against heat stress conditions. Under heat stress conditions genotypes showed significant different response and genotypes were divided into heat sensitive and heat tolerant ones. VI051062 and VI060131 were categorized as most heat tolerant and VI046554, while VI048594 were categorized as most heat sensitive ones. In second experiment twenty five okra genotypes screened out from one hundred okra genotypes in experiment # 1 in growth room, (twenty heat tolerant and five heat sensitive genotypes) were sown in summer 2014, in the field conditions at vegetable research area of Institute of Horticultural Sciences, University of Agriculture, Faisalabad. Genotypes were sown at three different sowing dates (02, April, 12, April and 22, April) to check the effect of heat stress on different morpho-physiological and yield attributes. All the cultural practices were kept same for all sowing dates and for all genotypes. There were four replications and each replication contained five plants. In this experiment genotypes VI051062 and VI060131 proved to be most heat tolerant while VI046554 and VI048594 proved to be most heat sensitive under field conditions on the basis of morpho-physiological and yield parameters In third experiment four okra genotypes, two tolerant (VI051062 and VI060131) and two sensitive (VI046554 and VI048594) selected from experiment # 2, were exposed to heat stress (45/35°C day/night temperature) under controlled environmental conditions, two weeks after exposure to heat stress plants were sprayed with proline (control, 1.0, 1.5, 2.0, 2.5 and 3.0mM) to optimize best dose of proline for enhancement the heat tolerance in okra VII genotypes. Morphological and physiological were studied to optimize the best dose of proline for enhancement of heat stress tolerance in okra genotypes. Results revealed that proline application @ 2.5 mM is best for enhancing the heat tolerance potential of okra. Fourth experiment was carried out to check the effect of optimized dose of proline (in experiment # 3) on the morphological, physiological and biochemical attributes of four okra genotypes two heat tolerant and two heat sensitive, under controlled environmental conditions at high temperature 45/35°C (day/night). It was noted that exogenous application of proline @ 2.5 mM significantly affected morphological, physiological, biochemical, water related and enzymatic attributeswhich in turn enhanced the heat tolerance potential of okra genotypes. It can be concluded from the study that by sowing the heat tolerant genotypes, identified in research, the growth period of okra can be extended. Exofenous application of proline @ 2.5 mM can further alleviate the drastic effects of high temperature and growing period can be extended.
Appears in Collections:PhD Thesis of All Public / Private Sector Universities / DAIs.

Files in This Item:
File Description SizeFormat 
Rashid_Hussain_Horticulture_2016_HSR_UAF_23.02.2017.pdfComplete Thesis2.41 MBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.