PERFORMANCE OF 3 SELECTION CYCLES FROM 4 SLICING CUCUMBER POPULATIONSHYBRIDIZED WITH A TESTER

Recurrent selection has been used as a breeding method to improve trai ts having low heritability such as fruit yield, earliness, and fruit s hape. The objective of this study was to measure the progress of recur rent selection in four slicing cucumber populations in terms of hybrid performance when crossed with a common tester. The four populations, North Carolina wide-base slicer (NCWBS), medium-base slicer (NCMBS), e lite slicer 1 (NCES1), and Pelt Alpha 1 (NCBA1) populations, which dif fered in their genetic diversity and mean performance, were developed using modified intrapopulation half-sib recurrent selection to improve fruit yield and quality. Eleven So families were taken randomly from each of three selection cycles (early, intermediate, and advanced) fro m each population. Those families were self-pollinated to form S-1 fam ilies, and the S-1 families were crossed to 'Poinsett 76', a popular s licing cucumber cultivar. The experiment was a split-plot treatment ar rangement in a randomized complete-block design with 22 replications p er population, with the four populations as whole plots and the three cycles as subplots. When 10 % of fruit were oversized >60 mm in diamet er), plants were sprayed with paraquat to defoliate them for once-over harvest. Plots were evaluated for total, early, and marketable yield and fruit shape. Recurrent selection for improved fruit yield and shap e per se resulted in improved hybrid performance of the NCWBS and NCBA 1 populations for fruit geld and shape rating when tested in the selec ted or nonselected environment. The NCWBS population had the largest g ain (21%) in hybrid performance averaged over all traits. In addition, early yield was improved an average of 18% from early to late cycles for each population. Even though the fruit yield and shape rating of ' Dasher II' was greater than the hybrid performance of each population mean for the same traits, several F-1 families within each population exceeded the fruit yield of 'Dasher II).