Classification of spring rapeseed genotypes by morphological and physiological traits related to salt tolerance

Agricultural productivity is severely affected by soil salinity, and the damaging effects of salt accumulation in agricultural soils have influenced ancient and modern civilizations. A split plot experiment was carried out to study the effect of salinity stress on morphological and physiological characteristics of several rapeseed genotypes. Three salinity levels (0, 150 and 300 mM NaCl) and 12 spring type rapeseed genotypes, were considered as the main and sub factors, respectively. Morphological parameters of shoot height, root length, root and shoot fresh weight, root and shoot dry weight, 100-seed weight, seed yield, osmotic potential, leaf water potential, leaf proline, Na+ content of leaf, K+content of leaf and leaves K+/Na+ ratio in rapeseed genotypes were studied. Analysis of variance showed highly significant differences between the studied genotypes in all traits. The methods of UPGMA were used to cluster analysis for grouping on the studied traits. Cluster analysis were classified the genotypes into two groups in which Heros and Comet were belong to the cluster with low mean with respect to all the traits. Therefore, these genotypes could be crossed with tolerant genotypes, Amica and Comet, for providing a genetic maps and QTL analysis. Furthermore, identification of tolerant and sensitive genotypes to salinity may provide a basis for molecular studies aiming to achieve a proper understanding of the mechanism of canola tolerance to salinity stress and involved genes in this process.