Morpho-physiological approaches to investigate lime-induced chlorosis in deciduous fruit trees species

Several deciduous fruit tree species are affected by iron chlorosis when grown in calcareous soils and worldwide research on rootstock breeding and screening in relation to iron deficiency is carried out. For many years the goal of our department has been to investigate morphological and physiological aspects related to lime‐induced chlorosis, and to identify markers usable as tools for tolerance screening of clonal rootstocks. Experimental strategies using pot, hydroponic and in vitro culture have been used to understand if they are able to originate suitable indicators on developmental and biochemical changes resulting from iron deficiency. Results risen up from in vitro trials suggest that iron deficiency sensitive system should work in a divergent way from that of bicarbonate system. Physiological and morphological data highlight diverse syndromes and behaviors among the genotypes, probably reflecting properly perception, regulation, and activation of biological answer system to iron deficiency and bicarbonate. Recently, quince (Cydonia oblonga Mill.) minus‐ and plus‐variants have been obtained by in vitro somaclonal variation to clarify the agonistic relationship between bicarbonate and iron deficiency sensitive systems, that in turn can induce the activation of two specific gene expression pathways.