Efeect of sowing dates on phenology, chlorophyll index, symbiotic parameters and yield of spanish bunch groundnut (Arachis hypogaea) cultivars

A field experiment was conducted at the Punjab Agricultural University, Ludhiana, Punjab to study the effect of sowing dates on phenology, SPAD value, symbiotic parameters and yield of groundnut cultivars during spring-summer season of 2018 and 2019. It was laid out in a split plot design in three replications with 4 sowing dates (25 February, 10 March, 25 March and 10 April) as main plot and 4 cultivars (SG 99, TG 37A, TAG 24 and J 87) as sub-plot treatments. Study revealed that crop sown on 25 February took 6, 10 and 12 days more for emergence (17 days) and 11, 20 and 25 days more for maturity (133 days) than 10 March, 25 March and 10 April sowing dates, respectively. With delay in sowing from 25 February to 10 April, reduction in SPAD value was observed whereas symbiotic parameters were increased up to 25 March sowing date. Crop sown on 10 March produced highest pod (5608 kg ha⁻¹) as well as kernel (4109 kg ha⁻¹) yield and was at par with 25 February and 25 March sowing dates for pod and with 25 February sowing date for kernel yield. All these sowing dates produced significantly higher pod and kernel yield than 10 April sowing. Whereas, haulm yield of groundnut sown on 25 March (7906 kg ha⁻¹) was significantly higher than 25 February and 10 March sowing dates. Cultivar SG 99 took significantly more number of days for maturity (123) than other cultivars (117–119 days). Differences among cultivars were observed for various physiological traits such as SPAD value, nodule dry weight per plant, leghaemoglobin content in root nodules and gynophores. Cultivar J 87 sown on 25 February produced significantly higher kernel yield (5370 kg ha⁻¹) than all other cultivars (SG 99, TG 37A, TAG 24) sown on different dates.