Is boron required to improve rice growth and yield in saline environment

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), BG402-4 (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 in the presence (80 mol m) and absence (0 mol m) of NaCl salinity whereas in solution culture, B was applied @ 1.5, 3.0 and 6.0 kg ha artificially to prepare saline (ECe 9.0 d Sm, SAR 5.46, pHs 7.8), and saline-sodic soils (ECe 9.0 d Sm, 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 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 in the saline and saline sodic soils. Nevertheless the highest B application @ 6 kg B ha 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.