Genetic analysis of safflower populations under water stress and nonstress conditions

An important target in safflower (Carthamus tinctorius L.) breeding programs is its genetic improvement aimed at enhancing drought tolerance. The present experiment was carried out to study the combining ability and the nature of gene action for agronomic and physiological traits in safflower populations under water stress and non-stress conditions. In this study, 28 entries (21 F-2 populations derived from a half-diallel cross along with their seven parental lines) were evaluated under the above conditions. The interactions of general and specific combining abilities (GCA and SCA) with irrigation regimes were significant for the measured traits. A higher ratio of GCA/SCA effects (>0.70) for all the traits under both conditions indicated the greater importance of additive gene effects for their genetic control. The parental lines C129 and K115 were identified as superior general combiners for high seed yield (367.4 and 228.4 under nonstress; 166.1 and 175.2 under stress), and the parental line Saffire showed a good GCA for early maturity (-3.36 and -2.69, respectively, under nonstress and stress conditions). It may, therefore, be claimed that these parents can be beneficially exploited as the genetic materials in safflower breeding programs to improve seed yield, early maturity, and developing drought-tolerant cultivars.