Interactive effect of salinity and boron application on growth and physiological traits of sunflower (Helianthus annuus L.) genotypes

Soil salinity is a major problem of agriculture in Pakistan. Permanent solution of salinity problem is removal of salts by leaching and drainage whic is expensive. So research efforts should involve profitable utilization of these lands through biological approaches. Considering these observations, this study was designed with the objectives to explore changes in growth and physiological attributes of different sunflower genotypes under interactive effect of salinity and boron. Vigorous seeds of selected genotypes (two tolerant, two sensitive) were sown in gravels. One week old seedlings were transplanted to 1/2 strength Hoagland's nutrients solution. Three days after transplantation the requisite salinity (control and 100 mM NaCl) and boron levels (0.05 mM B, 0.5 mM B and 1.0 mM B as H3BO3) were established in three installments. The arrangement of the experiment was split plot with three replications. The data regarding shoot and root fresh weights, relative water contents (RWC), membrane stability index (MSI), and leaf area (LA) were recorded. The results revealed that salinity and boron adversely affected the growth and physiology of sunflower genotypes with a higher effect in the case of combined stress. This study also showed that the growth reduction was more in the salt susceptible genotypes (Hysun-33, Hysun-38) than in the salt tolerant genotypes (SF-187, S-278).