Studies by Agricultural Research Service scientists indicate that cherries, red raspberries and apples share key genetic traits for disease resistance. These findings could help plant breeders develop more robust varieties that can better withstand pathogens, according to news release. 


ARS biologist Angela Baldo conducted genetic surveys of the three fruits to find markers for locating resistance genes that fight diseases and other stresses.  Baldo works at the ARS Plant Genetic Resources Unit in Geneva, N.Y.


Cherries, apples and red raspberries are members of the Rosaceae plant family and contain resistance genes found in many other plants. 


Working with several colleagues, Baldo found 75 markers for resistance genes in red raspberry. Most of the markers were unique, but they were anywhere from 50 percent to 87 percent similar to markers from other Rosaceae species.


One of the markers was linked genetically to Phytophthora root rot resistance. This discovery might someday help plant breeders develop hardier and more marketable varieties of red raspberry. 


Baldo also contributed to the identification of 90 resistance gene markers from sweet and sour cherry cultivars with different levels of resistance to cherry leaf spot and powdery mildew. 


The markers were compared with other Rosaceous markers that researchers have already linked with resistance to a range of pathogens.


The preliminary studies suggest there may be similarities between peach resistance gene markers linked to sharka, also known as plum pox, and cherry resistance gene markers linked to powdery mildew. If additional research confirms these findings, they could support more efficient methods for mapping resistance genes. 


Baldo and colleagues also helped find three new groups of resistance gene markers in some 300 wild apple accessions.  Plans are under way to map the gene markers and assess their links to regions of the apple genome that convey resistance to fire blight, apple scab and powdery mildew.