Exogenous growth regulators amplify the morpho-physiology, root architecture and dry-matter accumulation in seed potato

Enhancing the productivity of seed potato production systems by improving the size of the tubers is a primary concern. Punjab, a state located in the northwest region of India, meets 60% of the country's seed requirements. In order to optimize the morpho-physiological aspects, root structure, and overall yield of seed-sized tubers, research trials were carried out at Punjab Agricultural University, Ludhiana over two consecutive years. The trial consisted of 11 different treatments and was conducted using a randomized complete block design with three replications. The application of Gibberellic acid at a concentration of 200 ppm, at 45 and 60 days after sowing (DAS), resulted in significantly higher yields of seed-sized tubers measuring <4.5 cm. This treatment also exhibited superior root architecture parameters and accumulation of dry matter, outperforming all other growth regulation treatments. Compared to the untreated control group, the Gibberellic acid application led to a remarkable increase of 45.9% and 39.8% in seed-sized tuber yields. Furthermore, it significantly boosted the protein, starch, antioxidant (total phenols), sugar (total and reducing), and mineral content (nitrogen, phosphorus, and potassium) in the tubers, surpassing the effects of all other growth regulation treatments. These results suggested that the exogenous use of gibberellic acid (200 ppm) at 45 and 60 DAS substantially improved the physiology, root architecture, and yield of seed-sized tubers.