Abstract

Safflower (Carthamus tinctorius L.) is one of the major oilseed crops worldwide and its genetic improvement for oil yield is very important in breeding of this crop. Effective analysis of obtained dataset from breeding programmes is important at all stages of plant improvement. The genotype by trait (GT) biplot was used for two-way safflower dataset as various genotypes with multiple traits. For this propose, 64 safflower genotypes with specific characteristics were tested. The GT biplot explained 79% of the total variation of the standardized data. The polygon view of GT showed sevenvertex genotypes as 34, 43, 45, 24, 61, 58 and 59. Genotype 34 had the highest values for all of the measured traits except plant height, total biornass and 1000-seed weight. The genotype 58 and the other genotypes of this sector had good amounts of 1000-seed weight, while the vertex genotype 24 and its related genotypes which fall in its sector were good for plant height. Generally, based on vector view, ideal genotype and ideal tester biplots, it was demonstrated that the selection of high seed yield will be performed via number of seeds per capitulum, harvest index, main capitulum diameter, lateral capitulum diameter and number of capitulum per plant. Also, for genetic improvement of oil yield, traits seed yield and harvest index must be considered. These traits should be considered simultaneously as effective selection criteria evolving high seed or oil yielding safflower genotypes because of their large contribution to these traits. The genotypes 34, 42, 43 and 60 could be considered for developing desirable progenies in selection strategy of safflower improvement programmes. Such a similar outcome could be applied in the future to delineate predictive, more rigorous selection strategies as well as to help define breeding concepts for improvement of new safflower cultivars and other crops in the other areas of the world.