Photosynthetic efficiency among Indian peanut cultivars and influence of seasonal variation and zinc

Abstract

Sixty high yielding Indian peanut cultivars were studied for net photosynthesis (PN), transpiration (E), stomatal conductance (gs), water use efficiency (WUE), radiation use efficiency (RUE), SPAD chlorophyll meter reading (SCMR) and chlorophyll fluorescence (Fv/Fm) at 70–75 days and pod and fodder yields at harvest in field during both the Kharif (Wet) and Rabi-summer (Dry) seasons to find out the efficient cultivars and seasons. The dry season crop showed higher values of these parameters except E and Fv/Fm than that of wet season crop and application of Zn increased all these but reduced gs and SCMR. On an average, the peanut cultivars showed 29.9 and 19.4 lmol (CO2) m2 s–1 PN, 0.57 and 0.26 m s-1 gs, 11.4 and 13.2 m mol m-2 s-1 E, 2.67 and 1.49 WUE, 0.018 and 0.012 RUE, 38.2 and 36.3 SCMR and 0.843 and 0.850 Fv/Fm during dry and wet seasons, respectively. The foliar application of zinc as 0.2% zinc-sulphate, during dry season, influenced all these parameters, with an average of 30.6 and 29.3 lmol (CO2) m-2 s-1 PN, 0.54 and 0.60 m s-1 gs, 11.7 and 11.2 m mol m-2 s-1 E, 2.69 and 2.65 WUE, 0.019 and 0.018 RUE, 37.8 and 38.7 SCMR and 0.844 and 0.842 Fv/Fm with and without Zn, respectively. The study identified several photosynthetically efficient cultivars. There were 18 cultivars with high PN and gs, 18 cultivars with high PN and E and 17 cultivars with high PN and pod yield. Based on the overall performance the peanut cultivars being recommended are Tirupati 3, TG 37A, CSMG 884, RS 1, S 230, LGN 2, TPG 41 nand SG 99 for dry season and GG 20, Tirupati 4, M 197, ALR 2, JL 501 and RG 141 for wet season.