ASSESSMENT OF SENSITIVITY TO FROST IN OCHRUS CHICKLING (LATHYRUS-OCHRUS (L) DC) BY CHLOROPHYLL FLUORESCENCE ANALYSES

Ochrus chickling (Lathyrus ochrus (L.) D.C.) is a promising feed legum e for rain-fed farming systems in the Mediterranean environments of We st Asia and North Africa (WANA) because of its drought tolerance and r esistance to broom rape (Orobanche crenata Forsk.). However, it is hig hly susceptible to cold and improving its resistance would further imp rove its adaptation. The potential of the chlorophyll fluorescence tec hnique in screening for frost sensitivity in seedlings of five Lathyru s ochrus genotypes and one each of Vicia ervilia (L.) Wild and V. sati va L. was assessed by measuring the rate of rise in induced or variabl e chlorophyll fluorescence of fully developed leaflets after cold hard ening in the open and subsequent exposure to freezing. The method diff erentiated the highly frost-susceptible L. ochrus genotypes from the m ore tolerant Vicia species. Testing the technique with nine genotypes of L. ochrus in which the plants were established, cold-hardened and f rost-stressed under controlled conditions confirmed its sensitivity ev en to reveal the narrow inter plant differences that generally exist w ithin a cultivar or genotype to frost. It is therefore considered as a useful screening technique for cold/frost tolerance in L. ochrus.