Characterization and in vitro selection for iron efficiency inPyrus andCydonia

Summary Responses to low Fe were characterized in tissue cultures ofPyrus amygdaliformis andCydonia oblonga (quince), two species used as rootstocks for pear. Cultured shoots and plantlets ofP. amygdaliformis had a higher chlorophyll concentration and Fe²⁺/total Fe ratio than those ofC. oblonga when grown under low Fe conditions. This tolerance to low Fe was correlated with high Fe³⁺-reducing ability and medium acidification. The adaptive responses were manifested in roots of plantlets, shoot bases, root cultures, and cell suspension cultures. Shoots were regenerated from leaves of quince and subjected to Fe-deficient conditions. Two somaclonal variants (IE-1 and IE-2) were recovered; each displayed higher ability to reduce Fe³⁺ and acidify the medium. These variants may be useful as rootstocks for regions with calcareous soils, which limit Fe availability.