Mitigating terminal heat stress in wheat through micro-irrigation and foliar spray of osmoprotectants
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Date
2016
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Punjab Agricultural University, Ludhiana
Abstract
The present study entitled “Mitigating terminal heat stress in wheat through microirrigation and foliar spray of osmoprotectants” was carried out at Punjab Agricultural University, Ludhiana during rabi seasons of 2013-14 and 2014-15. The soil of experimental site was loamy sand in texture with normal pH and electrical conductivity, low in organic carbon and available N and medium in available P and K. In first experiment, foliar application of osmoprotectants was carried out to evaluate their effect on various physiological characteristics, crop growth and grain yield of wheat. The experiment was conducted in randomized complete block design with eleven treatments consisting of three osmoprotectants applied at three different concentrations, viz., thiourea @ 20, 40 and 60 mM, potassium nitrate @ 1, 2 and 3% and sodium nitroprusside @ 400, 800 and 1200 µg/ml along with water spray and control. During 2013-14, foliar application of sodium nitroprusside at 400 µg/ml, KNO3 2% and thiourea 20 mM recorded higher physiological parameters, i.e. chlorophyll index, gas exchange parameters, photosynthetic rate, relative water content and proline content than both water sprayed and control. During 2013-14, foliar application of sodium nitroprusside 400 µg/ml increased grain yield to the tune of 18.8 per cent, while the increase was 17.9 per cent by spray of KNO3 2% and 14.9 per cent by spray of thiourea 20 mM over control. During 2014-15, SNP 800 µg/ml, KNO3 3% and thiourea 40 mM performed better as compared to lower doses. The second experiment was carried out in randomised block design with thirteen treatments to evaluate the effect of combinations of three irrigation methods (check basin, drip and sprinkler irrigation) and four irrigation schedules (CPE:IW 0.6, 0.8, 1.0 and 1.2) along with recommended surface irrigation (7.5 cm depth) as control on growth, yield, water productivity and economics of wheat cultivation. The results showed that there was considerable improvement in plant height, leaf area index, dry matter accumulation, root growth parameters and grain yield in case of drip irrigation as compared to both check basin and sprinkler irrigation method. However, net return and B: C was higher in check basin method of irrigation. Among the irrigation schedules, plant growth, yield and net return increased markedly with increase in irrigation frequency, i.e. CPE: IW 0.6 to 1.2. Maximum water productivity was recorded in drip irrigation as compared to sprinkler and check basin methods during both the years
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Keywords
Wheat, osmoprotectants, micro-irrigation, grain yield, water productivity