No abstract

Wheat grain yield is affected by several biotic and abiotic factors. Among the abiotic factors heat stress is the most important factor that greatly affects the productivity of wheat. A study was carried out in loamy-sand soil to evaluate the effect of sowing at different thermal environments and its interaction with foliar spray of bio-regulators on growth indices and yield of wheat during rabi 2016–17 and 2017–18 at S K N Agriculture University, Jobner, Jaipur, Rajasthan. The experiment was laid out in a split plot design with four replications consisting of 24 treatments. Wheat sown at 20ºC temperature, reported maximum growth indices i.e. LAD, CGR, RGR and NAR at 30–60 DAS and 60–90 DAS which were significantly higher than D1 (sowing at 18ºC) and D3 (sowing at 22ºC). The significantly higher LAI was recorded under B4 (SA @200 ppm) over all other treatments, while it remained at par with B3, B7 and B8 at 60 DAS and B6 and B8 at 90 DAS. At 30–60 DAS and 60–90 DAS, significantly higher LAD, CGR and RGR were noticed under the treatment B4 (SA @200 ppm) which superseded over rest of the treatments while it remained at par with B8 except CGR at 60–90 DAS. It is concluded that salicylic acid @200 ppm may be sprayed on 20ºC temperature sown crop, plays a major role in mitigating the abiotic stress via creation of favourable micro-climate; thereby increasing the productivity.

Aim: The aim of the present study was to evaluate the effect of sowing at different thermal environments and its interaction with foliar spray of bio-regulators on yield and yield contributing traits in wheat. Methodology: The present study was conducted by using split plot design with four replications consisting of 24 treatments, namely, main plots: three sowing at different thermal environments (22oC, 20oC and 18oC) and sub plots: eight foliar spray of bioregulators (control, water spray, salicylic acid @ 100 ppm, salicylic acid @ 200 ppm, thio salicylic acid @ 100 ppm, thio salicylic acid @ 200 ppm, thioglycolic acid @ 100 ppm and thioglycolic acid @ 200 ppm). Results: The results indicated that sowing at 20oC recorded the maximum yield parameters viz, effective tillers/m row length, length of ear, no. of grains per ear, test weight, days to maturity and grain, straw and biological yield of wheat over sowing at 22oC and 18oC temperature. Sowing at different thermal environment treatments was found to be non-significant with harvest index of wheat. Among the foliar spray of bioregulators, the treatment B4 (SA @ 200 ppm) significantly increased the yield components and yield, while remaining at par with B6 (TSA @ 200 ppm) and B8 (TGA @ 200 ppm) proved superior in comparison to rest of the treatments. However, the significantly higher harvest index was obtained under B4 (SA @ 200 ppm) treatment and was statistically at par with all other treatments, except B1 and B2. Interpretation: It is concluded that salicylic acid @ 200 ppm at tillering (40-45 DAS) and ear emergence (60-65 DAS) stage may be sprayed on 20oC temperature sown crop is a viable option to improve wheat yield under semi-arid environment.