Genotype by Trait Biplot Analysis of Trait Relations in Safflower

In the present investigation, 81 safflower genotypes were studied in a 9×9 simple lattice design for several plants per plot (NPP), plant height (PH), the height of the first lateral branch (HFL), the height of the first lateral capitulum (HFC), stem diameter (SD), number of lateral branches per plant (NLB), number of main branches per plant (NMB), number of capitula per plant (NCP), number of seeds per main capitulum (SMC), number of seeds per lateral capitulum (SLC), seed yield (SY) and thousand seed weight (TSW). The genotype by trait (G×T) interaction biplot tool was used to indicate the pattern of G×T interaction two-way interaction data in a graph with 73% description of observed variation whereas the first principal component (PC) effect explained 49%, and the second PC, 24%, of the observed interaction variability. The vector view displayed that NCP with NMB, and SMC with SY were positively associated while there was a negative association between HFC with TSW, and between NLB with NPP. The polygon-view graph is divided into eleven sectors, and the sector of genotype G80 was a winner for most traits. Genotype G58 followed by genotypes G30, G33 and G72, were the most favorable genotypes in regard to SY while regarding this trait as a reference, SMC was identified as the most related trait which is followed by SLC, SD. Applying G×T biplot to the safflower multiple trait data demonstrated that this model visually showed the associations among seed yield with the number of seeds per main and lateral capitula followed by the number of capitula per plant and thousand seed weight, and provide ease of visual genotype comparisons and choosing. We found that choose of seed yield alone was not only dependent on the number of seeds per main and lateral capitula but also related to the other traits in safflower breeding.