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IS BORON REQUIRED TO IMPROVE RICE GROWTH AND YIELD IN SALINE ENVIRONMENT?

EHSAN-UL-HAQ MEHMOOD^1*, RIZWANA KAUSAR^2, MUHAMMAD AKRAM¹ AND SHER MUHAMMAD SHAHZAD²

Abstract: The nutritional functions of boron were investigated in improving rice growth and yield, both in solution and soil culture environments. Three rice cultivars [viz., KS-282 (salt-tolerant), BG-402-4 (mixed behavior) and IR-28 (salt-sensitive)] of differential salinity tolerant were used to investigate the ameliorative nutritional aspects of boron. Boron was applied @ 25, 50, 100, 200, 400 and 800ng B mL^-1 in the presence (80 mol m^-3) and absence (0 mol m^-3) of NaCl salinity whereas in solution culture, B was applied @ 1.5, 3.0 and 6.0 kg ha^-1 artificially to prepare saline (ECe 9.0 d Sm^-1, SAR 5.46, pHs 7.8), and saline-sodic soils (ECe 9.0 d Sm^-1, SAR 28.2, pHs 8.2). Application of B improved all growth parameters i.e., tillering capacity, shoot and root length, and shoot and root weight because of external B application @ 200-400ng mL^-1 in solution culture in the presence and absence of NaCl salinity. In shoot Na⁺ and Cl^- decreased; whereas K⁺ concentration and K ⁺: Na⁺ ratio improved because of B supplied to saline medium. The ameliorative effect on paddy and straw yield and paddy: straw ratio was recorded at all external B supplied as compared to control. The highest improvement was recorded at 1.5kg B ha^-1 in the saline and saline sodic soils. Nevertheless the highest B application @ 6 kg B ha^-1 had shown an adverse affect on paddy and straw production in saline sodic soils in all the three cultivars as compared with all other B rates and control. The beneficial effect of B was due to reduced shoot Na⁺ and Cl^- concentration and better ratio of K⁺ and Na⁺ in shoot. Seed setting was improved in all the three cultivars because of external B supply to saline and saline sodic soils.

¹Pesticide Quality Control Laboratory, Multan, Pakistan

²Instituite of Soil & Environmental Science, University of Agriculture, Faisalabad, Pakistan.