Assessment of Agrometeorological Indices in Summer Groundnut Cultivars in South Saurashtra Agro-Climatic Zone of Gujarat

Aims: To study the agrometeorological indices, heat use efficiency and phenothermal index of summer groundnut cultivars. Study Design: Strip Plot Design. Place and Duration of Study: The experiment was taken in summer 2024 at Instructional Farm, Department of Agronomy, College of Agriculture, Junagadh Agricultural University, Junagadh Methodology: The experiment contained three replication and twelve treatment combinations, where horizontal plot consisted of four different sowing dates viz., D1: 4th SMW, D2: 6th SMW, D3: 8th SMW and D4: 10th SMW and vertical plot consisted of three different groundnut varieties viz., V1: GJG-31, V2: GG-34 and V3: GG-37. The study assessed several agrometeorological indices viz., Growing Degree Days (GDD), Photothermal Unit (PTU), Heliothermal Unit (HTU), Hygrothermal Unit-I (HgTU-I) and Hygrothermal Unit-II (HgTU-II). The study also evaluated the Heat Use Efficiency (HUE) and Phenothermal Index. Results: The study also evaluated the Heat Use Efficiency (HUE) and Phenothermal Index. The results showed 4th SMW sowing time takes the highest GDD (2230 ℃ day), PTU (27426 ℃ day hrs.), HTU (21579 ℃ day hrs.) and HgTU-I (151772 ℃ per cent) while 10th SMW sowing time takes highest HgTU-II (54048 ℃ per cent). HUE is highest in 6th SMW sowing time (1.16 kg ha-1 day-1) and Phenothermal Index is highest in 10th SMW (19.94 ℃ day hrs./day). Among the varieties, GJG-31 variety takes lowest GDD (2107 ℃ day), PTU (26226 ℃ day hrs.), HTU (20082 ℃ day hrs.) and HgTU-I (142443 ℃ per cent), HgTU-II (48686 ℃ per cent) and Phenothermal Index (17.99 ℃ day hrs./day). GJG-31 have the highest heat use efficiency (1.1 kg ha-1 day-1). Conclusion: Based on this experiment it can be concluded that the GDD, HTU, PTU and HgTU-I decreased with delay in sowing and it was highest in 4th SMW. The highest HgTU-II and phenothermal index was observed in 10th SMW. HUE was found highest in the 6th SMW. Among the varieties, GJG-31 variety takes lowest agrometeorological indices and Phenothermal Index to reach the maturity respectively and had the highest HUE.