Evaluation location: California, United States
Two tests were conducted in rhizomanina-infested fields at Salinas, CA. Both were at the Spence Farm. Test 512 was in a field infested with the wild type strain of BNYVV. Test 1112 was in a field infested with the Rz1-resistance breaking strain of BNYVV. Trials were planted in April/May in a RCBD of single-row plots 2.74 m in planted length with 0.61 m between plots and 0.71 m row spacing. Stand count (number of plants per plot) was recorded 6-weeks post-planting. Stand count was not taken for Test 1112. Instead, a low, medium, or high plant stand was recorded. Plants were rated for disease as signs and symptoms of infection are seen, typically beginning in September. Evaluation for resistance to rhizomania was based on a composite visual score of foliar color and wilting. Scores for foliar yellowing attributed to rhizomania are evaluated on 0 to 9 scale, where 0 = very dark green with no yellowish plants, and 9 = 100% of the plants showing yellowing typical of rhizomania-susceptible varieties. When present, natural PM infection is scored from 0, clean leaves, to 9, indicating at least 90% or more of the leaf area is covered with visible mildew.
Excel file from Kelly Richardson 2010, 2011, 2012 and 2014 data with multiple worksheets
A general overview of the Rhizomania evaluation work at Salinas, California.