Relationship among vegetative growth and nutrient elements in the scion of different Persian lime accessions and its effect on WBDL phytoplasma

Nutrient elements have a significant role in plant physiology and metabolism, and the concentration of nutrients in the plant depends on plants genetic makeup and their interactions with biotic and environmental factors. A large percentage of Mexican lime (Citrus aurantifolia Swingle) orchards have been infected with witches’ broom disease of lime (WBDL) in various lime-growing regions in the Middle East. This study was conducted to assay the relationship among vegetative growth and nutrient elements in the scion of different Persian lime accessions and its effect on the activity of WBDL phytoplasma. For this purpose, 16 rootstock and scion combinations were considered including four scions of Persian lime accessions (IAC, Tahiti lime, Deperse lime and Persian lime) on four citrus rootstocks (Bakraei, Mexican lime, Volkamer lemon and sour orange). T-budding method was utilized for grafting, and some characteristics such as scion length and diameter growth and amount of nutrient elements in the leaves of the studied scions were measured. In addition, reaction of the grafted plants was assessed using inoculation with a WBDL-infected Mexican lime scion. Based on the results, detection of WBDL phytoplasma was later (116 days post-inoculation) in scions on the Volkamer lemon rootstock and earlier (40 days post-inoculation) in scions on the Mexican lime rootstock. WBDL symptoms were not observed in the grafted plants (on the Persnian lime scions) but were observed in all seedlings (non-grafted plants) except Volkamer lemon. The shortest incubation period of the disease was observed in the Mexican lime seedlings. A positive and significant correlation was observed between some nutrient elements such as zinc and manganese with vegetative growth. A significant positive correlation was observed between scion length, scion diameter and iron amount with the number of days to detect WBDL phytoplasma (NDDWP) (0.534*, 0.577* and 0.556*, respectively) as well as the significant negative correlation between sodium and chloride elements with NDDWP ( − 0.512* and  − 0.632*, respectively). According to the obtained results, it can be concluded that increase in the vigor of plant growth and high amount of iron in the plant as well as reduction of negative effects of sodium and chloride may decrease concentration of WBDL phytoplasma and delay the appearance symptoms of the disease and, consequently, WBDL spreading rate.