Citrus rootstock genotypes response to drought: alternation in morphology, physiology and leaf mineral content

Abstract

The potted seedlings (18 months old) of seven citrus genotypes were imposed to drought-rewater cycles for every 24 days to study the alterations in morpho-physiological traits and leaf mineral nutrients. The continued growth under drought was observed in Soh sarkar (11.88% more), RLC-7 (10.25% more) and Karna Khatta (10.74% more) as of normal conditions. Moreover, after re-watering, RLC-7 enhanced the plant height to the great extent (17%) as compared to drought. RLC-7, RLC-5 and Soh sarkar maintained a leaf area ratio even under drought condition, while it was inhibited in Jatti khatti and Karna khatta significantly under drought as compared to well-watered conditions. Moreover, reduction in the root volume in most of the rootstocks except RLC-5 and Soh sarkar was noticed. Most of the rootstocks were able to maintain intrinsic water use efficiency after rewatering except RLC-6. Chlorophyll ‘b’ enhanced under drought in RLC-5, RLC-6 and RLC-7, while it was inhibited in Soh sarkar at the end of the drought. Concomitantly, Soh sarkar and RLC-5 exhibited a noticeable alternation of mineral nutrients, having sharp increase of K (RLC-5), but P, Fe and Zn were relatively stable throughout the experiment as compared to start of drought and after rewater stage. From the study, it could conclude that Soh sarkar and RLC-5 (Citris jambhiri) can escape moderate drought. Further, it can also be argued that differential mechanism works for drought tolerance in RLC-5 and Soh sarkar genotypes.