Drought Stress Effects on Productivity of Fall Safflower Genotypes

Safflower as an original crop in Iran has high adaptability to different environmental conditions. Iran is one of the original areas of safflower as a drought and salinity tolerant crop. Therefor, safflower can be a suitable alternative crop for cultivation in marginal areas. The aims of research were studying the late season drought effects on seed and oil yields and its components of fall safflower genotypes in marginal border areas of Oroumieh lake. The study was carried out in East Azarbaijan Research Center for Agriculture and Natural Resources, Iran (46? and 2? E, 37? and 58? N) during 2008-9. A factorial experiment including 2 irrigation levels (non stressed and drought stress during seed filling stage) and 5 safflower genotypes (Padideh, Zarghan, Varamin 259, KW5 and KW8) based on randomized complete block design with 3 replications was used. During stress period relative water content(RWC), leaf temperature and finally seed and oil yields and its components were measured. The results showed that RWC, Paniculum diameter, panicula per plant, seeds in paniculum, seed and oil yields were significantly decreased and leaf temperature was significantly increased by water deficit. Significantly negative correlations among leaf temperature with RWC, seed and oil yields were seen. Also significantly positive correlations among RWC, seed and oil yields were achieved. Therefore, it is concluded that these indices can be used for determining late season drought effects on fall safflower genotypes. Among seed and oil yields with plant and capitulum formation height, capitulum diameter, capitula per plant, seeds in capitulum and 1000 seeds weight significantly positive correlations were seen, also between capitulum diameter with seeds in capitula, positive correlation achieved. Safflower plants with having higher capitulum diameter, indicated more seeds in capitulum and finally produced higher seed yield. Among studied genotypes, KW8 with having 3189 and 913 Kg ha-1 seed and oil yields respectively, showed higher yields. KW5, Padideh and Varamin295 were in next ranks respectively. It seems that these genotypes are suitable for cultivating in border areas of Oroumieh lake with marginal soil and late season drought and areas with similar climate.