Paper Title
ROOT ARCHITECTURE STUDY REVEALS THE BASIS OF EARLY HEAT STRESS TOLERANCE IN WHEAT (TRITICUM AESTIVUM L.) GENOTYPES

Abstract
Roots play an important role in early establishment of each and every plant. With respect to this, the present study was conducted to investigate the role of root architecture in early establishment of wheat crop under high temperature conditions. A screenhouse experiment was conducted on 12 selected (10 heat tolerant and two heat sensitive) wheat genotypes along with six check cultivars in Punjab Agricultural University Ludhiana during the year 2021-22. These twelve genotypes along with six check cultivars were grown under three sowing conditions (early (20th October), timely (14th November) and late (5th December) in polythene bags and PVC pipes respectively. The data was recorded at seedling (at 25 Days After Sowing (DAS) and at flowering stage. AT 25 DAS, the highest number (8) of seminal roots, seminal root length (35.90 cm) and lowest root emergence angle (58.4°) was recorded in the seedlings of heat tolerant genotype EWS 280 under early sown conditions over timely and late sown wheat genotypes. At flowering stage, the heat tolerant genotypes EWS 280 and EWS 145 had maximum (19) number of nodal roots under early sown conditions. The number of root branches were ranged from 48 to 84, 45 to 77 and 42 to 72 under early, timely and late sown conditions respectively. The heat tolerant genotypes had the maximum root volume and root length under early sown conditions, while the least root volume and root length was recorded in the heat sensitive genotypes EWS 171 and EWS 433 under late sown conditions. Thus, the present study enlightens the role of roots in early establishment of heat tolerant wheat genotypes under early sown conditions. Keywords - Roots, Architecture, Wheat, Heat Tolerant, Heat Sensitive, Genotypes, Emergence Angle