Cucurbit Genetics Cooperative Report 16:5-7 (article 3) 1993
Todd C. Wehner and Conrad H. Miller
Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695-7609
Most cucumbers (Cucumis sativus L.) in North Carolina are harvested 2 to 3 times per week for 2 to 4 weeks in two production seasons (spring and summer). Fruits are harvested by searching through the vines for marketable sizes. Since it is difficult to see fruits in the canopy, some fruits are not harvested each time. those becoming oversized before they are picked in the next harvests are unmarketable, resulting in lost yield.
Ease of harvest has been improved using machines, new cultivar types, and more efficient techniques. Harvest machines reduce the labor input where they can be adapted to the production system (*Haffar and Van Ed, 1984). New cultivar types such as gynoecious flowering permit fewer harvests for the same yield as monoecious types (Wehner and Miller, 1985). Techniques for improved harvest efficiency such as vine training can reduce vine damage, and provide a longer production period for the crop. We were interested in vine rolling for improved recovery of fruits hidden near the base of the plant.
The objective of this study was to determine if harvest was faster and easier if the vines were rolled over as they were picked.
Methods. The experiment was run at the Horticultural Crops Research Station near Clinton, NC. Seeds were planted in rows 1.5 m apart on raised beds. Plots were 9 m long with 1.5 m alleys at each end. Fertilizer was incorporated before planting at a rate of 90-39-84 kg-ha-1 (N-P-K) and a side dressing of N (34 kg/ha) was applied at vine tip-over stage. Irrigation was applied as needed up to three times a week for a minimum of 25 mm of water per week. Recommended cultural practices were used (Hughes et al., 1983).
Plots were planted 22 July, 1982, and thinned 2 August to a density of 86,450 plants*ha-1. Harvests were made Mondays and Thursdays 26 August to 7 September for pickling and 30 August to 10 September for slicing cucumbers. Cultivars tested were ‘Calypso’ pickle and ‘Slicemaster’ slicer, both gynoecious hybrids. Pollen was supplied with border rows of ‘Sumter’ pickle or ‘Poinsett 76’ slicer, both monoecious inbreds.
The experiment design was a randomized complete block with 5 replications and 2 harvest methods (conventional vs vine rolling). The pickling and slicing crops were kept separate in harvest and grading operations. Plots were harvested 4 times (twice weekly), and the fruits graded and weighed, Grades were the NC grades for pickles and USDA grades for slicers. NC grades were based on fruit diameter as follows: No. 1=0-26 mm, No. 2=27-38 mm, No. 3=39=50 mm,No. 4.50 mm. USDA grades were based on quality as specified by federal guidelines (USDA 1958). Harvests were timed for each of the methods, conventional and vine rolling. vines were rolled over on one side as a worker harvested that side, then rolled back the other way by the second worker. Vines were left in their rolled-up state after harvest, and were not laid back out over the soil. That resulted in the exposure of the base of the plant to sun and wind, and some stems and leaves were upside down.
Data were collected on fruit weight by grade, and summarized using analysis of variance. Treatment comparisons were essentially t-tests for conventional vs vine rolling harvest methods.
Results. Differences in yield between conventional and vine rolling were significant for fruit weight in pickling cucumbers but not for fruit value of pickling (Table 1) or for yield of slicing cucumbers (Table 2). Where the differences were significant, the vine rolling treatment resulted in lower yields (68% as much for pickles), and took longer (18% more for pickles, 2% more for slicers) than conventional plots. Vine rolling did, however, result in a significantly higher percentage of No. 1, and lower percentage No. 3 and 4 grade pickles than the conventional method (Table 1). In slicers, the vine rolling treatment produced fewer Fancy and No. 1 grade fruits than conventional, indicating more stress or less effective pollination (Table 2).
Vine rolling required more time to perform than conventional harvest, and resulted in lower yield. In the case of pickling cucumbers, vine rolling did shift the distribution of fruit sizes toward grade 1 and 2, and away from 3 and 4. That may be advantageous for producing small pickling cucumber sizes, but more frequent harvest would probably have the same effect without reducing the yield. Although there was less damage to the vines in the vine rolling treatment compared with conventional (data not shown), the effect was not translated into increased yield in the harvest crew, and improved the recovery of small grade pickles in the same way that vine rolling did. However, vine training would avoid the increased exposure of the base of the vine without leaving some vines turned upside down.
Table 1. Comparison of two multiple-harvest methods for yield and harvest time in pickling cucumbers.z
Harvest method |
Fruit yield |
Harvest time (sec/plot/harvest) |
Mean size gradey |
% size grades |
||||
Value ($/ha) |
Weight (Mg/ha) |
1 |
2 |
3 |
4 |
|||
| Conventional | 2477 | 23.9 | 128 | 2.7 | 9 | 34 | 38 | 19 |
| Rolledx | 2186 | 16.1 | 151 | 2.4 | 17 | 39 | 33 | 10 |
| LSD (5%) | NS | 2.2 | – | 0.2 | 4 | 6 | 1 | 6 |
| CV (%) | 15 | 6 | – | 3 | 15 | 9 | 2 | 24 |
z Data are means over 5 replications and 4 harvests. NS indicates F ratio not significant (5%).
y Grades are 1 to 4 for the NC sizes.
Vines were flipped over the row while harvesting each side.
Table 2. Comparison of two multiple-harvest methods for yield and harvest time in slicing cucumbers.z
Harvest method |
Yield (Mg/ha) |
Harvest time (sec/plot / harvest) |
Mean size gradey |
Fancy+ No. 1 (%) |
Culls (%) |
|
Fancy & No. 1 |
Marketable |
|||||
| Conventional | 20.4 | 27.7 | 120 | 1.1 | 66 | 10 |
| Rolledx | 11.3 | 18.7 | 122 | 1.5 | 50 | 19 |
| LSD (5%) | NS | NS | – | 0.3 | 12 | NS |
| CV (%) | 50 | 41 | – | 14 | 12 | 50 |
z Data are means over 5 replications and 4 harvests. NS indicates F ratio not significant (5%).
y Grades are 0 to 3 for the 4 USDA sizes, were 0=Fancy, 1-No. 1, 2=No.2, 3=cull.
x Vines were flipped over the row while harvesting each side.
Literature Cited
- Haffar, I. and G. Van Ee. 1984. A comparison of hand and machine harvesting systems for pickling cucumbers in Michigan. Amer. Soc. Agric. Eng. 84-1575.
- Hughes, G.R., C.W. Averre, and K.A. Sorensen. 1983. Growing pickling cucumbers in North Carolina. N.C. Agric. Ext. Serv. AG-315.
- U.S.D.A. 1958. United States standards for cucumbers (effective 1 March, 1958). Agric. Marketing Service, U.S. Dept. Agric., Wash. D.C.
- Wehner, T.C. and C.H. Miller. 1985. Effect of gynoecious expression on yield and earliness of a fresh-market cucumber hybrid. J. Amer. Soc. Hort. Sci. 110:464-466.