Selection for Freezing Tolerance in Chickpea (Cicer arietinum L.) by in vitro Culture

Freezing stress affected some vital processes of plant, and causing disturbance on the plant growth. In order to study the effect of low temperatures on freezing tolerance of chickpea (Cicer arietinum L.) a factorial experiment with 4 replications carried out using 3 chickpea genotypes (MCC496، MCC763 and MCC798) and 7 freezing temperatures (-4, -6, -8, -10, -12, -14 and -160C). Explants were cultured on MS medium with 2mg. l-1 BAP and 0. 125 mg. l-1 IBA. For acclimation, explants were transfered to 4ºC for 12 days. Then explants were freezed in thermo- gradient freezer. The percentage of survival and injury were determined after 3 weeks. Result showed that the effect of different freezing temperatures were significant on survival and injury percentage (P≤0. 05). By temperature decreasing, survival percentage decreased, wherease injury percentage increased but between 3 genotype differences were not significant. LT50 (injury percentage) in genotypes MCC763 and MCC798 were -15 ºC and in genotype MCC496 was -15/5 ºC. Also, LT50 (survival percentage) in 3 genotypes MCC496, MCC763 and MCC798, were -13, -12 and -12/5 ºC. This study suggests that in vitro screening of chickpea genotypes for cold tolerance is satisfactory and can be replaced by selection in the field, mainly due to its high repeatability.