|Mcgrath, J Mitchell - Mitch|
Submitted to: Experiment Station Bulletins
Publication Type: Experiment Station
Publication Acceptance Date: 5/9/2001
Publication Date: N/A
Technical Abstract: Two recent germplasm releases were planted in large selection plots at the Saginaw Valley Bean and Beet Research Farm. EL52 was released for its Rhizoctonia resistance, while SR96 was released primarily for smooth-root and high sucrose content. Neither release was selected for Cercospora nor Aphanomyces resistance, although their pedigrees include lines that do have etolerance to these diseases. The goal of this research was to reselect individuals from relatively large populations that showed enhanced tolerance to Cercospora and Aphanomyces. No seed treatments were used in these tests in order to select against seedling disease susceptibility. Plots were inoculated with Cercospora mid-July, but infection was low until mid-August. From mid-August, the disease progressed quickly. Plants that showed few signs of leaf spot infection relative to their neighbor plants were marked and harvested for seed increase. The severity of disease was less in EL52 than SR96. However, both releases had individuals with limite disease symptoms. For Aphanomyces selection, each release was in plots having a history of poor beet growth due to high seedling disease pressure. Emergence was poor for both EL52 and SR96, and growth of emerged plants was weak and slow. Survivors were harvested as potential resistant selections.