Search Results

You are looking at 21 - 30 of 131 items for

  • Author or Editor: Todd C. Wehner x
Clear All Modify Search

Monoecious cucumber (Cucumis sativus) plants generally produce enough pollen for fruit set. The amount of pollen required for fruit set depends on the number of pistillate flowers produced by the cultivar. ‘NC-Sunshine’ is a new monoecious slicing hybrid cucumber with a high percentage of pistillate nodes. Because of the high percentage of pistillate nodes, a pollenizer might be required to maximize pollination to get high total and early yield. Hence, an experiment was conducted at three locations to evaluate the effect of the pollenizer ‘Poinsett 76’ on yield of ‘NC-Sunshine’ compared with no pollenizer ‘Gray Zucchini’ squash (Cucurbita pepo). Differences (P ≥ 0.05) due to pollenizer, location, and the interaction of pollenizer and location on ‘NC-Sunshine’ yield traits were detected. Pollenizer influenced cucumber yield at two of three locations. Results indicated that the pollenizer ‘Poinsett 76’ significantly increased total, marketable, and early yield of ‘NC-Sunshine’. The percentage of early and marketable yield was also higher with the pollenizer ‘Poinsett 76’. In addition, the use of a pollenizer decreased cull yield. Therefore, a pollenizer is needed for monoecious hybrids having a high percentage of pistillate nodes.

Full access

Eighteen cucumber (Cucumis sativus L.) cultivars (15 oriental trellis and three standard American slicers) were grown on trellis and flat-bed production systems during the spring and summer seasons of 1995. Vine, flower, fruit quality, keeping ability, and yield traits were measured. Vine length, incidence of powdery mildew, fruit shape, fruit quality, fruit firmness, yield of Fancy plus No. 1 grade slicer fruits, marketable yield, and percentage of culled fruits were all higher when cultivars were grown on trellis support. Anthracnose damage, fruit length, fruit diameter, average fruit mass, fruit color, overall impression, fruit shriveling, seedcell size, branch number, percentage of staminate nodes, and total yield were not significantly affected by production system. The best cultivars for marketable yield (mass of Fancy, No. 1 and 2 grade slicers) were `Summer Top', `Tasty Bright', and `Sprint 440' on trellis support and `Sprint 440' and `Poinsett 76' on flat bed. The cultivars with the best fruit quality were `Tasty Bright', `Summer Top', and `Sprint 440' on trellis and `Poinsett 76', `Sprint 440', and `Tasty Bright' on flat bed. The best cultivars overall on the trellis production system were `Sprint 440', `Summer Top', `Tasty Bright', and `89-211', and the worst were `Sky Horse', `Hongzhou Green 55', and `Fengyan'. The best cultivars overall on the flat bed were `Poinsett 76', `Sprint 440', and `89-211', while the worst cultivars were `Sky Horse' and `Hongzhou Green 55'.

Full access

The use of a previously developed model for predicting harvest date in cucumber production systems is described. In previous research we developed a new method using daily maximum temperatures in heat units to predict cucumber harvest dates. This method sums, from planting to harvest, the daily maximum minus a base temperature of 60F (15.5 C), but if the maximum is >90F (32C) it is replaced by 90F minus the difference between the maximum and 90F. This method was more accurate than counting days to harvest in predicting cucumber harvest in North Carolina, even when harvest was predicted using 5 years of experience for a particular location and planting date.

Full access

The construction of a single-fruit seed extractor for cucumber is described. It increases the speed and ease of removing seeds from individual, mature cucumbers for later drying and planting. The machine saves about 47 seconds/fruit compared to hand methods and is suited to handling single fruit (or batches of up to 50) by researchers needing seeds from controlled pollinations. In 5 years of use, no reduction in seed recovery or germination has been observed using the seed extractor relative to hand harvest.

Full access

Increased fruit yield in slicing cucumber (Cucumis sativus L.) has been difficult to achieve since yield is quantitatively inherited with low heritability. From 1981 to 1993, four slicing cucumber populations differing in their genetic diversity (wide, medium, elite, and `Beit Alpha') were advanced through six to ten cycles of modified half-sib recurrent selection. The objectives of this research were to determine 1) the fruit yield and yield component means; 2) the correlations between yield components, between yield traits, and between components and yield; and 3) the change in means and correlations with selection for improved yield of four slicing cucumber populations. In 1994 and 1995, four families were randomly selected from three cycles (early, intermediate, and late) from each population and self-pollinated. Thirty plants from each S1 family were evaluated in 3.1-m plots in Spring and Summer 1995 and 1996 at the Horticultural Crops Research Station in Clinton, N.C. Plants were harvested and data were collected on number of branches per plant and nodes per branch, proportion of pistillate nodes, fruit set and shape, and total, early, and marketable yield. When averaged over all populations, seasons, and years, fruit yield and quality increased with selection while yield components remained unchanged with selection. Fruit yield and components differed between populations, seasons, and years. Most correlations between yield components and between yield components and fruit yield were weak, and strong correlations varied between populations, seasons, and yield components. Indirect selection of proportion of pistillate nodes has potential for improving yield for certain population-season combinations. Selection weakened many strong correlations between yield components and between yield and components. Changes in correlations often did not correspond with 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 component heritability, and better component selection methods need to be determined before component selection can be used to improve fruit yield.

Free access

Recurrent selection has been used as a breeding method to improve traits having low heritability such as fruit yield, earliness, and fruit shape. The objective of this study was to measure the progress of recurrent 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), elite slicer 1 (NCES1), and Beit Alpha 1 (NCBA1) populations, which differed in their genetic diversity and mean performance, were developed using modified intrapopulation half-sib recurrent selection to improve fruit yield and quality. Eleven S0 families were taken randomly from each of three selection cycles (early, intermediate, and advanced) from each population. Those families were self-pollinated to form S1 families, and the S1 families were crossed to `Poinsett 76', a popular slicing cucumber cultivar. The experiment was a splitplot treatment arrangement in a randomized complete-block design with 22 replications per population, with the four populations as whole plots and the three cycles as subplots. When 10% of fruit were oversized (>60 mm in diameter), 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 shape per se resulted in improved hybrid performance of the NCWBS and NCBA1 populations for fruit yield and shape rating when tested in the selected or nonselected environment. The NCWBS population had the largest gain (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 F1 families within each population exceeded the fruit yield of `Dasher II'.

Free access

Yield data for the major cucurbit crops in the United States have been collected and summarized. Yield trends are presented for cucumber (Cucumis sativus; processing and fresh-market), melon (Cucumis melo; muskmelon and honeydew), and watermelon (Citrullus lanatus) for the period 1951–2005. Data have been obtained from the U.S. Department of Agriculture, as originally reported by six of its units: Agricultural Marketing Service, Agricultural Research Service, Bureau of Agricultural Economics, Economic Statistics Service, National Agricultural Statistics Service, and Statistical Reporting Service. For all crops yields have been increasing over time, except for processing cucumber, for which yields seem to have reached a plateau by the end of the 1990s.

Full access

An experiment was conducted to determine the genetics of chilling resistance in cucumber (Cucumis sativus L.) inbred NC-76 that was developed from PI 246930, an accession from the U.S. Department of Agriculture germplasm collection. NC-76 was crossed with ‘Chipper’ and breeding line Gy 14 to produce F1, F1 reciprocal, F2, and BC1 generations for evaluation. Cucumber seedlings at the first true leaf stage were placed in growth chambers set at 4 °C for 7 h and a photosynthetic photon flux of 500 μmol·m−2·s−1. Segregation in the F2 fit a 3 : 1 inheritance pattern, with resistance being dominant. The backcross of the F1 to the susceptible parent produced a 1 : 1 ratio, confirming that chilling resistance was from a single gene. The single dominant gene controlling chilling resistance in NC-76 was given the symbol Ch.

Free access

A heat unit model developed in a previous study was compared to the standard method (average number of days to harvest) for ability to predict harvest date in cucumber (Cucumis sativus L.). Processing and fresh-market cucumbers were evaluated in 3 years (1984 through 1986), three seasons (spring, summer, and fall), and three North Carolina locations. The model predicted harvest date significantly better than the standard method for processing, but not for fresh-market cucumbers.

Free access