Objective 1: Crosses of KZB resistant lines, PI567336A, PI567598B, and PI567301B, were made during 2014 to a susceptible line for resistance loci mapping. Winter nursery will be used to advance these to the F2 generation. Mapping populations of PI227687 and Noir 1 (C2 and D1a sources) were advanced to the F2:3 generation and will be available in 2015 for confirmation experiments.
Objective 2 & 3: During 2014 the KZB population across the Southeast did not reach the high numbers we have observed in previous years, which made it difficult to screen for KZB resistance in the field. Since KZB numbers in the field did not reach the threshold to reduce yield (25 adults/plant at R1 stage), the data collected from our field experiments was not useful. Instead, we were able to confirm 2013 Midville data using a growth chamber assay (see Objective 5).
Objective 4: Seed of Japanese PIs from the USDA Germplasm Collection was requested and in-creased as needed in order to begin screening these lines in 2015.
Objective 5: During the summer of 2014 the KZB colony produced ~100 egg masses a week, which enabled the KZB growth chamber assay to be validated. PI567336A and PI567598B, the two most KZB resistant lines from the 2013 Midville test, were confirmed as resistant lines in the new growth chamber cup assay.
Objective 6: A third year of large plot yield testing with the Benning NILs was performed at the Southeastern Branch Research and Education Center (SEBRC) near Midville, GA in 2014. Four IPM treatments were evaluated, early May and late June planting date and treatment with or with-out a single insecticide application at the KZB threshold of one nymph per sweep. A low population of KZB was observed on all treatments and a moderate beet armyworm infestation occurred in the late planted treatments, however yield impact was insignificant. The yield was significantly higher in most of the Benning treatments planted in early May as compared to late June.
Objective 7: Due to the low KZB population in 2014, the Georgia State Variety Test could not be evaluated for KZB resistance.