ARS | Publication request: EVALUATING CRANBERRY GERMPLASM FOR FRUIT ROT RESISTANCE

Submitted to: North American Cranberry Research and Extension Workers Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: September 16, 2005
Publication Date: October 24, 2005
Citation: Johnson-Cicalese, J., Vorsa, N., Polashock, J.J. 2005. Evaluating cranberry germplasm for fruit rot resistance. North American Cranberry Research and Extension Workers Annual Meeting. Page 23-25.

Technical Abstract: A collection of cranberry germplasm (Vaccinium macrocarpon) was evaluated for resistance to the cranberry fruit rot disease complex. This germplasm was collected across the geographic range of cranberries, from both wild sites and cultivated beds. The accessions were planted in 1995 in 1.5 m x 1.5 m plots. In 2003 and 2004, the plots were rated for fruit rot, using a 1 to 5 scale, where 1=no rotten fruit, and 5=almost all fruit rotten. Seventy percent of the selections had severe rot (392 plots out of 562 had a rating of ‘5’), and only 6% showed some resistance (33 plots with a rating of ‘1’ or ‘2’). To confirm the ratings, fruit was collected from 34 selections and counted with fruit rot ranging from 5% to 100%. Ratings and counts were highly correlated (r=0.92), indicating that the ratings were a good estimate of percent rot. There was a close correlation between the 2003 and 2004 fruit rot ratings (r=0.80) and fruit rot counts (r=0.70). In order to determine the genetic relatedness of selected resistant accessions, DNA fingerprinting was done (SCARs method). Several distinct types were identified including: ‘Budd’s Blues’ (US88-30), a number of Budd’s Blues-types (US93-34, US94-161, US89-3), Holliston-types (US88-1, US88-110), ‘Cumberland’ (US88-79), and accessions from a wild site in Pilgrim Lake, MA. Budd’s Blues has long been recognized as having fruit rot resistance, but has very poor yield. Some resistant selections have been used in crosses and their progeny are being evaluated. In 2004, progeny from a ‘Stevens x US89-3’ cross had a lower mean rot rating than a ‘Stevens x susceptible selection’ cross, suggesting that resistance is a heritable trait.