Screening lentil (Lens culinaris) for cold hardiness under controlled conditions

Abstract

This study describes the development of a highly repeatable cold screening procedure for lentil (Lens culinaris Medik.) using controlled conditions which involve first, acclimation of the plants at the vegetative stage in a growth chamber and second, freeze testing in a freeze chamber. The seeds were first germinated in Petri dishes and then planted in styrofoam trays with individual cells. Initial growing temperatures in the growth chamber for two weeks were 25 °C day and 10 °C night with a 12 h photoperiod. In the third week the photoperiod was changed to 10 h and in the fourth the temperatures were changed to 10 °C day and 0 °C night to acclimate the plants. Using a modified freeze chamber (household deep freezer), a freeze test temperature of −15 °C, following a 6–8 weeks acclimation period (because both acclimation times had the same effect for cold tolerance of the genotypes), at 2 and 3 °C/h cooling rate, and an exposure time of 3 h at −15 °C were appropriate to detect significant (P<0·01) differences among several lines at a comparatively low degree of injury for the most cold-hardy genotypes.