Evaluation of Foliar Chemical Sprays for Improving Seed Quality of Field Pea (Pisum sativum var. arvense L.) under Terminal Heat Stress

Abstract

Field pea is a significant pulse crop globally, with one-third of the global population relying on it as a staple food. Nonetheless, due to shifting climate conditions and the occurrence of elevated temperatures, heat stress has emerged as a significant factor restraining its productivity. Therefore, the current research was carried out with the aim of formulating an effective approach to address heat stress. The field trial took place during rabi 2023-24 and rabi 2024-25 in the Department of Seed Science and Technology at Chandra Sekhar Azad University of Agriculture and Technology, Kanpur. 12 different Chemicals were used for the present study. Heat stress was found to have a significant influence on the seed quality parameters. Germination percentage and Vigour Index I (VG I), 100 seed weight, seedling length, seedling dry weight reduced significantly under late sown condition. Similar trend was observed for Vigour Index II. (VG II) Foliar sprays with different chemicals viz. Salicylic acid (400ppm), Thiourea (400ppm), Salicylic acid (800ppm), Thiourea (200ppm), Ascorbic acid (10ppm), KCL (1%) were carried out at vegetative (booting stage) and Anthesis stage. Seeds harvested from heat stressed environment showed a significant increase seed quality parameters when sprayed with various foliar sprays. The findings also indicated that spraying salicylic acid at 400ppm and Thiourea at 400ppm effectively enhances multiple seed quality attributes such as 100 seed weight, germination rate, and seedling height (cm). The germination of seeds and VG I and II also displayed upward trends. The use of thiourea notably increased soluble sugars and proline levels in leaves, likely preserving a longer duration of green area with elevated leaf chlorophyll, which ultimately improves seed quality traits and may enhance heat tolerance. Therefore, all foliar applications successfully alleviated heat stress effects; however, salicylic acid at 400ppm and Thiourea at 400ppm were identified as the most effective.