Effects of drought on citrus natural genotypes

Citrus tolerate low temperature and weak drainage. Growing citrus in warm regions, expose them to drought. This research was conducted to investigate drought effect on relative water content, ion leackage, malondialdehyde, soluble sugars, potassium and calcium nutrients in nucellar seedlings of citrus natural genotypeswith two susceptible and tolerant rootstocks in factorial test based on randomized completely design with three replications in glasshouse conditions. Factors included commercial Citrus genotypes and two level of irrigation (optimum irrigation and withholding irrigation). The results showed that Poncirus because of lower ion leakage (31.85 %), lower malondealdehyde accumulation (134.4 nm/gdw) and higher calcium content (57 mg/gdw) compared with other genotypes was more tolerant to drought. Rough lemon because of higher malondealdehyde accumulation (356.9 nm/gdw), high ion leakage (69.43 %) and lower calcium content (32.63 mg/gdw) compared with other genotypes, was susceptible to drought. Genotype of Shelmahalleh because of high ion leakage (77.17 %) and slight total soluble carbohydrate accumulation was susceptible to drought after Rough lemon. Therefore, we could consider ion leakage as a proper physiological marker for drought tolerance with regard to means comparison and its good correlation to survival time.