Evaluation the Correlation between Different Traits and Plant Performance in the Spring Safflower Varieties

摘要

Safflower (Carthamus tinctorius L) is a native of Iran oil seed. This crop is compatible with the environmental conditions in the country as well; this is especially true in areas exposed to non-biological stresses such as drought and salinity. The study of abiotic stress in plants has advanced considerably in recent years. However, the majority of studies testing the response of plants to changes in environmental conditions have focused on a single stress treatment applied to plants under controlled conditions. In contrast, in the field, a number of different stresses can occur simultaneously. These may include conditions such as drought, extreme temperature or high salinity and may alter plant metabolism in a novel manner that may be different from that caused by each of the different stresses applied individually1,2. Drought and heat shock represent an excellent example of two different stresses that occur in the field simultaneously, especially in semi-arid or drought-stricken areas1-4. Although drought stress and heat shock have been extensively studied5-7, relatively little is known about how their combination impact plants. We identified sucrose accumulation as a possible defense mechanism of plants against this stress combination. Our long-term objective is to develop different plants and crops with enhanced tolerance to a combination of drought stress and heat shock. A combination of drought stress and heat shock is common to many semi-arid or drought-stricken regions of Nevada. Developing plants and crops with enhanced tolerance to this stress combination will contribute significantly to Nevada agriculture and economy and directly address one of the major NAES research priorities. The results of causality analysis for correlation coefficients between the grain yields with the regression model traits showed that either three moisture regimes, the grain yield per bush is most influenced by the number of grain per boll and the number of boll per bush. But these direct effects are reduced by their negative and indirect effects. The 1000 grain weight has positive and relatively high effects on grain yield per bush in both stress and stress free environments, but because of important indirect and negative affection by the number of boll per bush, the number of grain per boll and the days to %100 flowering, it showed positive and relatively low correlation with the grain yield per bush. In general, the results indicate that the number of grain per boll and the number of boll per bush can be used as two appropriate selection indexes in safflower breeding programs in order to improved grain yield. Meanwhile it seems that the varieties with more 1000 grain weight produce more grain yield in both conditions