FRUIT YIELD AND YIELD COMPONENT MEANS AND CORRELATIONS OF 4 SLICING CUCUMBER POPULATIONS IMPROVED THROUGH 6 TO 10 CYCLES OF RECURRENT SELECTION

Increased fruit yield in slicing cucumber (Cucumis sativus L.) has bee n difficult to achieve since yield is quantitatively inherited with lo w heritability. From 1981 to 1993, four slicing cucumber populations d iffering in their genetic diversity (wide, medium, elite, and 'Beit Al pha') were advanced through six to ten cycles of modified half-sib rec urrent selection. The objectives of this research were to determine 1) the fruit yield and yield component means; 2) the correlations betwee n yield components, between yield traits, and between components and y ield; and 3) the change in means and correlations with selection for i mproved yield of four slicing cucumber populations. In 1994 and 1995, four families were randomly selected from three cycles (early, interme diate, and late) from each population and self-pollinated. Thirty plan ts from each SI family were evaluated in 3.1-m plots in Spring and Sum mer 1995 and 1996 at the Horticultural Crops Research Station in Clint on, N.C. Plants were harvested and data were collected on number of br anches per plant and nodes per branch, proportion of pistillate nodes, fruit set and shape, and total, early, and marketable yield. When ave raged over all populations, seasons, and years, fruit yield and qualit y increased with selection while yield components remained unchanged w ith selection. Fruit yield and components differed between populations , seasons, and years. Most correlations between yield components and b etween yield components and fruit yield were weak, and strong correlat ions varied between populations, seasons, and yield components. Indire ct selection of proportion of pistillate nodes has potential for impro ving yield for certain population-season combinations. Selection weake ned many strong correlations between yield components and between yiel d and components. Changes in correlations often did not correspond wit h changes in trait means. Based on this research, selection for yield components would not be advantageous for improving fruit yield in all slicing cucumber populations. Additional yield components, yield compo nent heritability, and better component selection methods ne ed to be determined before component selection can be used to improve fruit yie ld.