Gain for Pickling Cucumber Yield and Fruit Shape Using Recurrent Selection

Abstract

Qualitative traits of cucumbers (Cucumis sativus L.) such as disease resistance have been improved significantly during the past 30 yr. On the other hand, quantitative traits such as yield, earliness, and fruit shape have been improved less. The objective of this study was to determine the progress that could be made on such traits with recurrent selection in three pickling cucumber populations (NCMBP, NCEPI, and NCH1). During population improvement, one or two replications of 200 to 335 half‐sib families were evaluated in the spring season for total, early, and marketable fruits per plot, a fruit shape rating, and a simple weighted index (SWI = 0.2 × total yield / 2 + 0.3 × Early yield + 0.2 × % marketable yield / 10 + 0.3 × quality). Families from each population were intercrossed in an isolation block during each summer with remnant seeds of the best 12% selected with the index. Progress was evaluated by means of a split‐plot treatment arrangement in a randomized complete block design with 32 replications in each of two seasons (spring and summer). Whole plots were the three populations, and subplots were the 10 to 11 cycles (Cycles 0–9 plus cheeks). Populations were improved for performance in a selected (spring season) as well as a non‐selected environment (summer season). Greatest gains were made for the NCMBP population, with an average of 54% gain from Cycle 0 to 9 over the five traits, and for early yield, with an average of 65% gain from Cycle 0 to 9 over the three populations. In other trials, NCH1 had the best mean performance. Based on those results, modified half‐sib recurrent selection can be used to improve fruit yield and quality of NCMBP, NCEP1, and NCH1 populations. Further studies should be made on NCMBP because it had the greatest gain per year, and on NCH1 because it had the highest mean performance.