Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2012
Publication Date: 9/20/2012
Citation: Johnson, R.C., Petrie, S.E., Franchini, M.C., Evans, M. 2012. Yield and yield components of winter-type safflower. Crop Science. 52:2358-2364. Interpretive Summary: Safflower is traditionally a spring sown crop grown in diverse regions worldwide, principally for its high quality seed oil. Winter hardy safflower, allowing fall planting, would provide important management alternatives for farmers. In this study winter hardy safflower developed in the Inland Northwest was compared under fall and spring planting regimes to determine if and to what extent fall planting could improve seed production. Tests were completed at three locations and over three years. Minimum average temperatures during December and January always well below freezing with annual extremes ranging from -11°C to -26°C. Fall planted winter types produced an average of 66% more seed than when planted in the spring, and matured about two weeks earlier. The higher seed production was associated with more seeds per unit area than for spring plantings. The results show the potential of winter hardy safflower to substantially increase seed production.
Technical Abstract: Safflower (Carthamus tinctorius L.) is a minor yet widely grown oil seed crop adapted to semi-arid regions. The nascent development of winter adapted safflower, allowing fall planting,could substantially increase seed production over spring planting. In this study four winter type safflower accessions and two spring cultivars were planted in the fall and spring and compared in seven year-location combinations from 2006 to 2009. The locations were Central Ferry WA, Pullman, WA and Pendleton, OR, USA. For all year-location combinations the minimum average temperatures during December and January were always below freezing, with annual extremes ranging from -11°C to -26°C. Complete or extensive winter mortality of fall planted, spring type cultivars resulted little or no seed production. Seed production of fall planted, winter type germplasm, however, averaged 310 g per m2, 66% more than when spring planted, and anthesis of fall planted germplasm averaged 16 days earlier than when spring planted. In 2008-09 the advantage to fall planted winter types was exaggerated by poor spring stands at Central Ferry, but at Pullman dryland production was high for both fall planted (380 g per m2) and spring planted (290 g per m2) winter types, with only one winter type accession producing more then when spring planted (P<0.05). Increased production of fall planted winter type germplasm was closely associated with increased seeds per m2 resulting from either more capitula per m2 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.