Open AccessGenetics of Partial Resistance AgainstVerticillium dahliaeRace 2 in Wild and Cultivated Lettuce
Author(s) -
Germán V. Sandoya,
María José Truco,
Lien Bertier,
Krishna V. Subbarao,
Ivan Šimko,
Ryan J. Hayes,
Richard W. Michelmore
Publication year - 2021
Publication title -
phytopathology
Language(s) - English
Resource type - Journals
eISSN - 1943-7684
pISSN - 0031-949X
DOI - 10.1094/phyto-09-20-0396-r
Subject(s) - verticillium dahliae , lactuca , verticillium wilt , biology , quantitative trait locus , germplasm , locus (genetics) , race (biology) , cultivar , verticillium , genetics , plant disease resistance , botany , gene
Lettuce (Lactuca sativa) is one of the most economically important vegetables in the United States, with approximately 50% of the domestic production concentrated in the Salinas Valley of California. Verticillium wilt, caused by races 1 and 2 of the fungal pathogen Verticillium dahliae, poses a major threat to lettuce production in this area. Although resistance governed by a single dominant gene against race 1 has previously been identified and is currently being incorporated into commercial cultivars, identification of resistance against race 2 has been challenging and no lines with complete resistance have been identified. In this study, we screened germplasm for resistance and investigated the genetics of partial resistance against race 2 using three mapping populations derived from crosses involving L. sativa × L. sativa and L. serriola × L. sativa. The inheritance of resistance in Lactuca species against race 2 is complex but a common quantitative trait locus (QTL) on linkage group 6, designated qVERT6.1 (quantitative Verticillium dahliae resistance on LG 6, first QTL), was detected in multiple populations. Additional race 2 resistance QTLs located in several linkage groups were detected in individual populations and environments. Because resistance in lettuce against race 2 is polygenic with a large genotype by environment interaction, breeding programs to incorporate these resistance genes should be aware of this complexity as they implement strategies to control race 2.