PHYSIOLOGICAL AND BIOCHEMICAL EFFECT OF PLANT GROWTH REGULATORS AND BORON ON POLLEN FERTILITY AND YIELD OF RICE (Oryza sativa L.) UNDER WATER STRESS
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Date
2022-08-10
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guntur
Abstract
The present investigation entitled “Physiological and Biochemical Effect of Plant Growth Regulators and Boron on pollen fertility and yield of rice (Oryza sativa L.) under water stress” was undertaken at Agricultural College Farm, Bapatla during late kharif, 2020-21. The experiment was laid out in a split plot design with two main treatments i.e., M0 - no water stress and M1 – water stress and eight sub treatments viz., no spray (S0), 25 ppm of GA foliar spray (S1), 0.01 mg of Brassinosteroids foliar spray (S2), 2.5 ppm of Boron foliar spray (S3), 25 ppm of GA + 0.01 mg of Brassinosteroids foliar spray (S4), 25 ppm of GA + 2.5 ppm Boron foliar spray (S5), 0.01 mg of Brassinosteroids + 2.5 ppm of Boron foliar spray (S6), 25 ppm of GA + 0.01 mg Brassinosteroids + 2.5 ppm of Boron foliar spray (S7) with three replications.
The results of the study revealed that, significant differences were observed among the main treatments, sub treatments and their interactions. Plant height decreased under water stress conditions, and the decrease was 11.4 per cent over the irrigated conditions. Foliar spray of 25 ppm of GA + 0.01 mg Brassinosteroids + 2.5 ppm of Boron at flowering stage increased the plant height by 17.3 per cent over the control plants.
Leaf water potential was decreased by two folds over the irrigated rice crop. Foliar spray of 25 ppm of GA + 0.01 mg Brassinosteroids + 2.5 ppm of Boron helped to increase the leaf water potential of the rice crop. Higher membrane injury index was recorded by the water stress compared to irrigated conditions, indicating increased lipid peroxidation under water stress conditions. Foliar spray of 25 ppm of GA + 0.01 mg Brassinosteroids + 2.5 ppm of Boron helped in minimizing the damage to cellular membranes by recording lesser membrane injury index values.
In the present study, pollen characters viz., pollen fertility, percent pollen germination, protein content in pollen, total soluble sugars in pollen were adversely affected under water stress. Percent pollen germination, protein content in pollen, total
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soluble sugars in pollen were reduced by 8.1, 48.8 and 69.6 per cent over the irrigated rice crop. Foliar spray of 25 ppm of GA + 0.01 mg Brassinosteroids + 2.5 ppm of Boron exhibited superior performance in enhancing the pollen characters under water stress conditions. Proline content in leaves was increased by 91 per cent under water stress conditions over the irrigated crop. Foliar spray of 25 ppm of GA + 0.01 mg Brassinosteroids + 2.5 ppm of Boron significantly increased the proline content in leaves by 28.6 per cent compared to untreated control plants.
In the present study, the yield parameters viz., number of panicles m-2, length of the panicle, number of filled spikelets per panicle, sterility percentage, test weight and yield were decreased by 17.0, 8.5, 21.8, 36.3, 16.0 and 13.7 per cent, respectively, under water stress conditions over irrigated crop. Foliar spray of 25 ppm of GA + 0.01mg of Brassinosteroids +2.5 ppm of Boron increased the number of panicles m-2, length of the panicle, number of filled spikelets per panicle, sterility percentage, test weight and yield increased by 6.3, 14.7, 17.3, 50.8, 18.9 and 21.2 per cent respectively over the control under water stress conditions.
Based on the results obtained in the present investigation, it can be concluded that the morpho-physiological, pollen characters, seed yield and its components were drastically reduced when the rice crop was exposed to water stress during flowering and anthesis stages, that reflected the reduction on the above parameters. Foliar spray of 25ppm of GA + 0.01mg of Brassinosteroids +2.5 ppm of Boron improves the pollen characters, growth, yield and its components of rice crop under normal as well as water stress conditions. The use of 25 ppm of GA + 0.01mg of Brassinosteroids +2.5 ppm of Boron at flowering and anthesis stages especially under water stress conditions could alleviate the negative effects of water stress on growth and yield of rice crop by improving the pollen characteristics of the crop and maintaining less membrane injury index, higher pollen germination percentage, protein content in pollen, total soluble sugars in pollen, proline content in leaves which helped the rice crop to ameliorate the adverse effects of water stress at flowering and anthesis stages. Hence, foliar spray of 25 ppm of GA + 0.01mg of Brassinosteroids + 2.5 ppm of Boron at 100 DAS at flowering stage in late sown rice crop to ameliorate the adverse effects of water stress.
Description
PHYSIOLOGICAL AND BIOCHEMICAL EFFECT OF
PLANT GROWTH REGULATORS AND BORON ON POLLEN FERTILITY AND YIELD OF RICE (Oryza sativa L.) UNDER
WATER STRESS