PHYSIOLOGICAL AND BIOCHEMICAL RESPONSES OF SEED PRIMING IN MAIZE (Zea mays L.) UNDER SALINITY STRESS
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Date
2023-11-30
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Acharya N G Ranga Agricultural University
Abstract
The present investigation entitled “Physiological and biochemical responses of seed priming in maize (Zea mays L.) under salinity stress” was undertaken in pot culture at Net house, Department of Crop Physiology, Agricultural college, Bapatla and field study at Farmer field, Cherukuru village, Bapatla, respectively during rabi season of 2021-22 to understand the impact of different priming treatments on physiological and biochemical components under salinity stress which in turn influence the productivity of maize. The pot culture and field experiment were taken up in completely randomized design (CRD) and randomized block design (RBD) with 7 treatments and replicated thrice. The treatments comprised of T1: Normal water irrigated (control), T2: 100 mmol L-1 of NaCl, T3: 200 mmol L-1 of NaCl, T4: 100 mmol L-1 of KCl, T5: 200 mmol L-1 of KCl, T6: 100 mmol L-1 1 of CaCl2.2H2O and T7: 200 mmol L-1 of CaCl2.2H2O.
The data on morpho-physiological parameters viz., germination percentage root-shoot length and seedling vigor were recorded at 15 and 30 days in pot culture study and germination percentage, number of days to emerge, plant height, drymatter production, leaf area and relative water content were recorded at 30, 60 and 90 days in field experiment. Biochemical parameters viz., proline and superoxide dismutase activity and chemical constituents viz., Na+, K+ and Ca+2 were estimated at vegetative and reproductive stages. The data on yield and yield components were recorded at harvest.
Under pot culture study, seed priming with CaCl2. 2H2O 200 mmol L-1 (T7) and CaCl2. 2H2O 100 mmol L-1 (T6) resulted in an increased germination percentage (14.2 and 10.6%), seedling vigor (27.3 and 29 %), root and shoot length (25, 24.5 and 20, 19.8 %) over control.
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Under field conditions, seed priming with CaCl2. 2H2O 200 mmol L-1 (T7) and CaCl2. 2H2O 100 mmol L-1 (T6) resulted in an increase in germination percentage (20.7 and 19.2 %), days to emergence, plant height (21.3 and 18.36 %), maintained higher leaf area and higher RWC in leaves (17.91 and 16.93 %) with higher drymatter partitioning (30.01 and 27.60 %) than the control (T1). Higher drymatter partitioning at 90 days after sowing indicated the positive impact of seed priming with these chemicals in accumulating drymatter.
Biochemical parameters like proline content and superoxide dismutase activity in leaf increased with seed priming treatment of CaCl2. 2H2O 200 mmol L-1 (T7) and CaCl2. 2H2O 100 mmol L-1 (T6). Seed priming with CaCl2. 2H2O 200 mmol L-1 (T7) recorded the lowest Na+/K+ ratio and Na+/Ca+2 ratio than the remaining treatments. All these biochemical parameters and lower Na+/K+ and Na+/Ca2+ ratio contributes for alleviating salinity stress in maize cultivated in coastal regions, where the salinity is the major problem.
Seed priming significantly increased the yield and yield attributes. Among all the treatments, seed priming with CaCl2. 2H2O 200 mmol L-1 (T7) and CaCl2. 2H2O 100 mmol L-1 (T6) produced higher yield and it is associated with more number of rows per cob, test weight, cob length.
Overall, it is concluded from the study that seed priming with CaCl2. 2H2O 200 mmol L-1 (T7) and CaCl2. 2H2O 100 mmol L-1 (T6) has shown good performance in rice fallow maize in enhancing the productivity by altering the physiological and biochemical constituents of the plant under salinity stress conditions.