Generation mean analysis to determine genetic components of drought tolerance in safflower (Carthamus tinctorius L.)

Safflower (Carthamus tinctorius L.) is one of the important oilseed crops grown commercially in Iran. The production of cultivars with high seed yield and oil content is the most important purpose of safflower breeding. Study of genes action to improve morphological traits especially under drought stress condition is very important. For this purpose, an experiment was conducted in 2013- 2015 in the researching farm in Isfahan, Iran using the generations of the crosses between two pure lines (KIR1015×Ac-Sunset) under drought stress and non-stress conditions based on randomized complete block design with three replications. The results of generation mean analysis showed that for plant biomass in both stress and control conditions and for plant seed yield, number of head per plant in control condition m and [a] were the best fitted. For number of head per plant and number of branches in stress condition and for 100 seed weight in control condition, m, [a] and [d] were shown to be the best fit of generation means. The dominant variance of plant seed yield, 100 seed weight and number of branch in stress condition and plant height, plant seed yield, 100 seed weight and number of branch in control condition were higher than additive variance. Broad sense and narrow sense heritabilities of oil content were 59.82 and 89.47 in control and drought stress conditions, respectively. Yield traits such as plant seed yield, number of head per plant and oil content were controlled by additive effects, which suggest scope for breeding and selection for improved drought tolerance in safflower.