Document Type: Research Paper
MSc of Plant Breeding, Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-8311, Iran.
Isfahan University of Technology
MSc student of Plant Breeding, Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-8311, Iran.
Development of drought-tolerant cultivars is hampered by a lack of effective selection
criteria. In this research, response of 36 genotypes of rapeseed from seven species of Brassica
including B. napus, B. rapa, B. juncea, B. carinata, B. oleracea, B. nigra and B. fruticulosa was
assessed under three moisture levels (no stress, mild stress and intense stress) in the field during
2011-2012. Five drought-tolerance indices were calculated: stress tolerance (TOL), stress
susceptibility index (SSI), mean productivity (MP), geometric mean productivity (GMP) and
stress tolerance index (STI). Increasing water stress levels caused significantly more reductions
in the seed yield of all species. Species B. napus had the highest yields in normal and intense
stress conditions while B. carinata showed better performance in mild stress condition.
Correlation coefficients revealed that among drought tolerance indices, GMP, STI and MP are
superior criteria for selecting high-yield genotypes under stress and non-stress conditions.
B. napus and B. carinata were the most drought tolerant while B. rapa and B. oleracea were the
most susceptible species of Brassica based on yield potential. Application of principle
component analysis (PCA) for distinguishing drought and susceptible species are discussed.