assessment of freezing tolerance in lentil genotypes (lens culinaris) by electrolyte leakage index

lentil (lens culinaris. medik) is one of the major cool season pulse crops which could suffer damage under severe cold. some physiological parameters such as electrolyte leakage (el) have been used to assess the response of crops to cold conditions. in order to evaluate the possibility of using the el index for assessing the freezing tolerance of lentil genotypes, a factorial experiment carried out with seven lentil genotypes (mlc7, mlc60, mlc185, mlc225, mlc357, ghazvin and robat) and nine freezing temperatures (0, -3, -6, -9, -12, -15, -18, -21 and -24oc) on the base of completely randomized design with three replications on the fall 2008. results showed that, in all genotypes, el was increased with decreasing the temperature, and there was significantly difference (p<0.05) between genotypes for el. robat and mlc7 had the highest (28/5%) and the lowest (19/4%) el%, respectively. the rate of el% increasing with decreasing the temperature also varied between genotypes, and slop of el curve in mlc225 and ghazvin was more than other genotypes. there were differences between genotypes for temperature of maximum el%. mlc7, mlc185, mlc225 and robat genotypes reached their maximum el% at -21°c, whereas temperature of maximum el% were -15°c for mlc357 and -18°c for mlc60 and ghazvin genotypes, respectively. there was also significantly difference between genotypes for lt50el and that ranges were from -10.7oc in (mlc357) to -16.2oc in (mlc225).