Evaluation of French bean genotypes for high temperature tolerance using Temperature Induction Response (TIR) technique Chaukhande Paresh1, Shetru Aghora, Hunashikatti Laxman*, Biradar Geeta, Singh Bijendra1 ICAR-Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Bangalore-560089 1ICAR-Indian Institute of Vegetable Research, Varanasi-221 305, U.P *Corresponding author, E-mail: laxmaniihr@gmail.com
Online published on 26 December, 2017. Abstract French bean is a cool season legume crop requires a temperature of 17°C-28°C for ideal growth. It is grown mainly during kharif and rabi seasons. But its cultivation is severely constrained during summer months due to prevailing high temperatures. Further, under climate change conditions high temperature episodes are likely increase and considerably affect pod yield. The identification of suitable cultivars is a prerequisite for adaptation to high temperature situations. Thus, the temperature induction response (TIR) technique, which involves exposure of seedlings to sub lethal temperatures to induce inherent cellular tolerance and consequent exposure to challenging temperatures was standardized and employed for screening French bean genotypes for high temperature stress tolerance. Two day old French bean seedlings were subjected to various challenging temperatures from 43°C to50°C for 3 hours and were allowed to recover at room temperature for 72 hours. Based on the least survival (11%) and highest growth reduction (92%) during recovery, 45°C for 3 hours was identified as challenging temperature. Consequently the induction temperature was identified by subjecting French bean seedlings to different induction temperature regimes. The gradual induction temperature from 30°C to 40°C for 3 hours at which 60% of the seedlings survival was observed during recovery and identified as the optimum induction temperature. Subsequently, ten French bean genotypes were screened by subjecting them to the standardized induction temperature of 30°C-40°C for 3 hours followed by challenging temperature of 45°C for 3 hours. The genotypes showed differences in percent seedling growth reduction during recovery period over control. The genotypes, (IC-525224 x IC-525239) IPS-1, (IC-525224 x IC-525239) 1–12 and Arka Anoop, with 60%, 65.27%, 66.30% reduction in seedling growth showed tolerance to high temperature stress. In this study we standardized the TIR technique as a screening method to evaluate and identify temperature tolerant French bean genotypes. Top Keywords French bean, High temperature tolerance, TIR, Induction temperature, Challenging temperature. Top |