Plot of PC1 versus PC2, showing associations among traits in the first year. Traits are: plant height (PH), height of the first lateral branch (HFL), height of the first capitulum (HFC), stem diameter (SD), number of lateral branches (NLB), number of main branches (NMB), number of capitula of lateral branches (NCLB), number of capitula of main branch (CMB), number of capitula of plant (NCP), seeds of main capitulum (SMC), seeds of lateral capitulum (SLC), seeds’ weight of main capitulum (SWMC), seeds’ weight of the lateral capitulum (SWL), weight of main capitulum (WMC), weight of lateral capitulum (WLC), thousand-seed weight (TSW), weight of single plant (WSP) and yield of single plant (YSP).