Yield and Yield Components of Winter‐Type Safflower

Abstract

ABSTRACTSafflower (Carthamus tinctorius L.) is a minor yet widely grown oil seed crop adapted to semiarid regions. The development of winter adapted safflower, permitting fall planting, could substantially increase seed production. Our objective was to compare seed production of winter‐type and spring‐type safflower under fall and spring planting regimes. From 2006 to 2009 four winter‐type safflower germplasms and two spring cultivars were compared at Central Ferry, WA, Pullman, WA, and Pendleton, OR, in seven year–location combinations. For all years and locations the minimum average winter temperatures in December and January were always below freezing, with annual extremes ranging from ‐11 to ‐26°C. Extensive winter mortality of fall‐planted, spring‐type cultivars generally resulted in little or no seed production. For each year, seed production of fall‐planted, winter‐type germplasm was always higher than when spring planted (P < 0.05), averaging 310 g m‐2 or 66% more. That advantage was also observed at all locations within years except Pullman and Pendleton in 2009. Anthesis of fall‐planted germplasm averaged 16 d earlier than when spring planted. Increased production of fall‐planted winter‐type germplasm was most closely associated with increased seeds per square meter resulting from more capitula per square meter or seeds per capitulum. The results showed that fall‐planted winter‐type safflower has the potential to substantially increase seed production compared to spring types.