Champagne QTL
Loquat canker is a serious bacterial disease caused by Pseudomonas syringae pv. eriobotoryae, which causes carcinomatous lesions on various parts of the tree, reducing vigor and fruit productivity. The pathogen is classified into three groups, A, B, and C, based on pigment production in the medium and the formation of degreening lesions on leaves. pse-c from 'Shiromogi' has been reported to be resistant to group C bacteria, and is controlled by a pair of recessive genes that locate in the third linkage group. The resistance breeding has been progressing, as it has been reported that pse-c is controlled by a pair of recessive genes and loci in the third linkage group. However, there is a concern that the emergence and spread of races that violate pse-c-derived resistance may lead to future morbidity of resistant varieties, and there is an urgent need to breed highly resistant varieties that utilize the 'Champagne' resistance gene, which is different from pse-c. Therefore, we conducted linkage mapping using resistance segregants derived from 'Champagne' and identified the resistance gene regions by QTL analysis.