Tolerance to lime-induced iron chlorosis of Asian pear rootstocks (Pyrus spp.)

Abstract

This study was conducted to evaluate the resistance of Asian pear rootstocks to lime-induced iron chlorosis when grown in calcareous soil. Two experiments were conducted in greenhouse condition, using three pear rootstock species: Pyrus xerophila Yü, P. betulaefolia Bunge, and P. calleryana Decne). Plants were grown over 90 days in pots filled with calcareous soil. Difference in iron chlorosis tolerance was estimated by chlorophyll contents by using chlorophyll meter readings, iron contents in leaves, and growth parameters of plants. Among the three pear rootstocks, P. xerophila showed higher chlorophyll and iron content in fully expanded apical leaves than did P. betulaefolia and P. calleryana in high pH, calcareous soil. It was further confirmed in the grafting experiment with the 'Housui' cultivar. These results confirmed that P. xerophila has a higher tolerance to lime-reduced iron chlorosis. However, further plant evaluation under field conditions is needed to verify whether P. xerophila can replace the widely used, P. betulaefolia in the Asian pear producing areas with high pH and calcareous soil, especially in the northwestern region of China.