بررسی برخی خصوصیات فیزیولوژیک و عملکرد هیبریدهای ذرت (Zea mays L.) تحت شرایط تنش شوری

A great part of lands under corn cultivation are affected by different levels of salt stress. This study was conducted in order to determine the effect of different levels of salt stress on yield and some physiological characteristics of corn plants. Two experiments were carried out in greenhouse (a factorial based on randomized complete blocks design with 3 replications), and field (a split plot based on randomized complete blocks design with 3 replications) at College of Agriculture, Shahid Bahonar University, Kerman, Iran. Treatments included 4 levels of irrigation water salinity (2, 4, 6 and 8 dS/m) and seven corn hybrids (SC-700, SC-500, SC-404, SC-704, SC-647, SC-301 and Maxima). During the growing period, leaf samples were taken from greenhouse-grown plants and their physiological characteristics such as chlorophyll fluorescence and ion leakage were measured. Grain yield was determined in the field plots. Results revealed that salt stress decreases chlorophyll index and photochemical efficiency of PSII of leaf tissues due to increasing original fluorescence (FO) and decreasing maximum fluorescence (Fm). Meanwhile, increasing the salt stress increased ion leakage. Results also showed that high salinity decreased the grain yield. The highest grain yield was obtained in plots with the lowest salinity level. Correlation coefficients showed that Fo and Fm parameters don't have significant correlation with salinity. While, Fv/Fm index had a positive relationship with salinity tolerance. The highest chlorophyll index, photochemical efficiency of PSII, membrane stability and grain yield was obtained for SC-704 hybrid. Therefore, it was the most tolerant hybrid and was recommended as a resistant cultivar against salinity stress.