Identification of drought resistance of rapeseed (Brassica napus L.) during germination stage under PEG stress

The growth indicators of 10 different varieties of rapeseed during the germination stage including seed germination stress index, relative germination rate, radicle / plumule ratio, root volume and so forth were measured under PEG stress, and the principal component analysis method was adopted to identify the drought resistance of rapeseed with multiple indicators. The four-grade drought-resistance evaluation indicator system was proposed, in which, the seed germination stress index, relative germination rate, root length stress index, seedling height stress index and relative root volume were the primary evaluation indicators, the relative germination potential, relative water content index of cotyledons and relative root length / seedling height ratio were the secondary evaluation indicators, and the relative radicle / plumule ratio and dry matter stress index were the third and fourth reference evaluation indicators. Based on the clustering result of drought-resistance value (D value) by using the screened indicators, the 10 tested varieties were divided into 3 groups with high, moderate and low drought resistance respectively.