Comparative Transcriptome Analysis Reveals Novel Candidate Resistance Genes Involved in Defence against in Strawberry.

Crown rot, caused by , is a devastating disease of strawberry. While most commercial octoploid strawberry cultivars ( × Duch) are generally susceptible, the diploid species is a potential source of resistance genes to . We previously reported several genotypes with varying degrees of resistance to .

Examining Phenotypic Traits Contributing to the Spread in Northern European Potato Crops of EU_41_A2, a New Clonal Lineage of .

Until recently, genotypes of were regionally distributed in Europe, with populations in western Europe being dominated by clonal lineages and those in northern Europe being genetically diverse because of frequent sexual reproduction. However, since 2013 a new clonal lineage (EU_41_A2) has successfully established itself and expanded in the sexually recombining populations of northern Europe. The objective of this study was to study phenotypic traits of the new clonal lineage of , which may explain its successful establishment and expansion within sexually recombining populations.

Use of a Rainfall Frequency Threshold to Adjust a Degree-Day Model of Ascospore Maturity of Venturia inaequalis.

Estimates of ascospore maturity generated by a model developed previously in New Hampshire, United States, were compared with the cumulative release of ascospores in southern Norway as monitored by volumetric spore traps at one site for 12 years, and at two additional sites for 2 years. In locations and years with frequent rain events, model-estimated ascospore maturity closely approximated observed ascospore release. However, in years with protracted dry periods of 1 to 3 weeks with no or little rain, not only was spore release delayed, but release continued to lag behind predicted maturity even after several rain events subsequent to the dry interval.

Genetic variation between Phytophthora cactorum isolates differing in their ability to cause crown rot in strawberry.

Analysis of 44 isolates of Phytophthora cactorum, isolated from strawberry and other hosts, by AFLP showed that the crown rot pathotype is different from leather rot isolates and from P. cactorum isolated from other hosts. 16 of 23 crown rot isolates, including isolates from Europe, Japan, Australia, and New Zealand, were identical in an analysis based on 96 polymorphic bands from seven primer combinations.