Analysis of generation means and components of variance for parthenocarpy in cucumber (Cucumis sativus L.)

Parthenocarpy (seedless fruit) has potential for increasing yield in cucumber (Cucumis sativus var. sativus L.). To determine the inheritance of parthenocarpy in gynoecious cucumber, P-1, P-2, F-1, F-2, BC1P1, and BC1P2 generations derived from crossing two non-parthenocarpic gynoecious inbred lines [Gy8 (P-2; processing type) and 'Marketmore 80' (P-2; MM, fresh market type)] with a highly parthenocarpic inbred line [2A (P-1; processing type)] were evaluated for fruit number in a greenhouse at Arlington, Wisc. in 1999 (designated 2A x Gy8 1999) and in the open-field at Hancock, Wisc. in 2000 (designated 2A x Gy8 2000 and 2A x MM 2000). There were significant location and location x generation interaction effects, and therefore generation means analyses were conducted separately for each location. The minimum numbers of effective factors controlling parthenocarpy were estimated to be at least one (2A x Gy8 1999), two (2A x Gy8 2000) and four (2A x MM 2000). Results suggest that selection for parthenocarpy for multiple hand harvest operations will likely be more effective than that for once-over machine harvest operations. However, the selection efficiency will likely vary across different populations and environments.