Evaluation of late season drought effects on seed and oil yields in spring safflower genotypes

Authors: BAHMAN PASBAN ESLAM, HASSAN MONIRIFAR, MASTANEH TAHER GHASSEMI

Abstract: Seed and oil yields, their components, and the relationships among yield and related traits were measured in 5 spring safflower (Carthamus tinctorius L.) genotypes, Local Arak, Local Esfahan, Sina, KH_{23-57}, and Goldasht, under nonstressed and water deficit conditions imposed from late flowering (80% flowering) to maturity. The studies were conducted in loam soil at the Research Center for Agriculture and Natural Resources of East Azarbaijan, Iran (46°2'E, 37°58'N) during 3 successive years (2005-2007). According to the significant decrease in the number of seeds per capitulum, 1000-seeds weight, harvest index, and seed and oil yields under water deficit conditions, it seems that drought during the seed filling stage decreases seed and oil yields, mainly through their components. The number of capitula in a plant, a main yield component in safflower, was positively correlated with seed and oil yields. Positive correlations among harvest index, seed oil, and seed and oil yields were obtained. It seems that harvest index may be the most important characteristic for selecting spring safflower genotypes under normal and drought conditions. Results of path analysis revealed that spring safflower genotypes, by having higher seed oil and 1000-seeds weight values, could be cultivated in areas with late season droughts, and spring safflower genotype selection based on plant and capitulum height would be effective. Among the genotypes, Goldasht, with 1412 and 358 kg ha^{-1} seed and oil yields, respectively, showed the lowest values of yield. Other genotypes showed similar seed and oil yields, while Local Arak produced higher seed and oil yields. It was determined that Local Esfahan, Sina, KH_{23-57}, and especially Local Arak could be grown at Khosrowshahr and areas with similar climates (cold and semiarid, according to the Köppen climatic classification) under normal and late season drought conditions.

Keywords: Drought stress, path analysis, safflower, seed and oil yields

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