Effect of boron on growth indices, physiological traits and productivity of rice (Oryza sativa) under north-west Indian conditions

Abstract

An experiment was conducted during the rainy season (kharif) of 2019 at the Punjab Agricultural University, Ludhiana, to explore the role of boron (B) in improving seed filling, vascularisation and yield of rice (Oryza sativa L.). The field experiment comprising 14 treatments, viz. foliar application of boron (B) @ 24, 28, 32 and 40 millimolar (mM) at boot-leaf stage (BL) or at 1 week after boot-leaf stage (1 WABL) as well as at both the stages (BL+1 WABL) along with foliar application of water and control (unsprayed), were laid out in randomised complete-block design, with 3 replications. Plants sprayed with 24 mM B at different stages showed improved photosynthetic efficiency in terms of chlorophyll content, carotenoid content and hill-reaction activity of leaf chloroplasts. Also, the yield-attributing traits, viz. 1,000-grain weight, panicle weight and panicles/m2, were significantly higher in plants treated with 24 mM B at BL + 1 WABL, followed by plants treated with 24 mM B at 1 WABL, which were similar to that treated with 24 mM B at BL or at 1 WABL. Increasing B concentration above 24 mM showed negative impact on the growth and yield of rice. Thus, foliar spray of 24 mM B at BL or 1 WABL may be used to improve the productivity of rice.