SCREENING OF CAMELINA (Camelina sativa L.) DOUBLED HAPLOID LINES FOR FREEZING TOLERANCE IN THE SEEDLING STAGE

Freezing stress is an important abiotic stress that limiting the yield and the spatial distribution of many important crops. This study was undertaken to screen 136 doubled haploid (DH) lines of camelina (Camelina sativa L.) along with four canola (Brassica napus) cultivars (Hyola 401, Lord, Roska and Cascade) as experimental control under freezing stress conditions (-14 degrees C for 6 h) to identify lines with high or low level of tolerance to freezing stress for further studies. First, a protocol was developed for large scale screening of camelina germplasm under freezing stress conditions. For this purpose, an experiment with different freezing temperatures (-5, -10, -15 and -20 degrees C) was conducted to find an appropriate temperature that discriminated best between genotypes (i.e. the LT50 temperature). The LT50 values for camelina lines were varied between -10.2 and -17.1 degrees C with an average of -13.94 degrees C for all of the camelina lines. Therefore, we selected the -14 degrees C exposure for 6 h as an appropriate temperature to screening of camelina lines. The principal components of measured parameters (LT50, survival percentage, relative conductivity and scoring) was using principal component analysis that determine freezing-tolerant and freezing-sensitive lines. Among 136 doubled haploid lines, some lines (58, 62 and 101) had higher level of freezing tolerance and some of them (8, 16, 32, 91 and 107) were freezing sensitive. The selected lines in a preliminary freezing screening are useful for further evaluations.