Autumn growth and its relationship to winter survival in diverse safflower germplasm

Abstract

The relationship between several autumn growth traits and winter survival was determined in 11 diverse safflower (Carthamus tinctorius L.) accessions grown at Central Ferry and Pullman, WA, USA. The safflower was sown in September 2002 and 2003 and plant population counts were taken 6-8 wk after emergence, and after the last frost in the spring to calculate winter survival. Growth factors including plant habit and height were also measured in the autumn. The Pullman plots in 2003-2004 were lost during an usually cold and windy November, but otherwise survival ranged from 90% for BJ-27, an introduction from China, to zero for the cultivar Saffire. Winter survival was negatively correlated with more upright plant habit (r = -041**, n = 97) and plant height (r = -0.29**, n = 97). However, some accessions with low plant habit (prostrate growth) and low height values had relatively poor survival. The results show that BJ-27 has sufficient winter survival to achieve over-winter safflower production for many areas. Autumn plant habit and height can predict the potential for winter survival, but physiological factors related to cold acclimation appeared to determine if that potential is realized.