Cucurbit Genetics Cooperative Report 10:2-3 (article 2) 1987
Comparison of Fruit-Set Concentration of Pickling
Cucumbers under Greenhouse and Field Conditions
Haim Nerson, Harry S. Paris, Zvi Karchi, Anneke Govers, Menahem Edelstein
and Yosef Burger
Department of Vegetable Crops, Agricultural Research Organization,
Newe Ya'ar Experiment Station, P.O. Haifa, Israel
The shortage and expense of hand labor for multiple harvest of pickling
cucumbers are major factors gearing this crop toward mechanized once-over
harvest. Accordingly, breeding of new cucumber cultivars for the pickling
industry is focused on improving yield concentration. New cultivars of pickling
cucumbers are released annually by public and private breeders, and this
new genetic material needs to be evaluated for suitability under different
cultural practices and climates before it is recommended to the growers.
Plot size is an important consideration for the evaluation of fruit-set
concentration in pickling cucumber cultivars. Plots that are too large result
in wasted effort and plots that are too small may not give accurate information
Results of field experiments have indicated that plots as small as 2 or
3 m2 can give dependable results (1,2). Our objective here was
to determine if fruit-set concentration potential under field conditions
could be accurately predicted under greenhouse conditions in winter using
6 plants per cultivar.
For this objective 39 pickling cucumber cultivars were grown in a heated
greenhouse (minimum night temperature 16°C) at Newe Ya'ar during
the winter season of 1982. There were 6 plants per cultivar and the plants
were trained to grow on cord hung from stiff wire. The plants were grown
on soil mounded on straw bales, distance between plants in the row was 25
cm. A hive of honeybees was provided for pollination. These same cultivars
were sown in the open field in April 1982 at 2 locations, Bet haShitta in
the Yizre'el Valley and Bet She'an in the Bet She'an Valley. These 2 locations
differ in climate and especially soil properties. In the fields, the plants
were grown in double rows on raised beds, 2m between bed centers, at a density
of 100,000 per hectare. Each cultivar had 4 replications of 6m2 each. A simulated once-over harvest was conducted in the greenhouse and
in the fields when 10% of the fruits were oversized. The number of marketable
fruits (20-50 mm diameter) per plant is presented in Table 1. Calculation
of correlation coefficients among locations shows no correlation between
the Newe Ya'ar greenhouse and Bet haShitta or Bet She'an (r=0.15 and r=0.09,
respectively) but a highly significant (P <0.01) correlation (r=0.58)
exists between Bet haShitta and Bet She'an. The main conclusion is that
data obtained under greenhouse conditions using a small number of plants
cannot serve to predict fruit-set concentration potential under field conditions.
Table 1. Number of fruits produced per plant in a
simulated once-over harvest under greenhouse (at Newe Ya'ar) and field (Bet
haShitta and Bet She'an) conditions.
z Sex expression determined in the greenhouse. G indicates <1 male flower
per plant; PF indicates ratio of male flowers to female flowers <1.0; M indicates ratio of
male flowers to female flowers ≥1.0.
Literature Cited
- Smith, O.S. and R.L. Lower. 1978. Field plot techniques for selecting
increased once-over harvest yield in pickling cucumbers. J. Amer. Soc.
Hort. Sci. 103:92-94.
- Wehner, T.C. and W.H. Swallow. 1984. Optimum plot size for once-over
harvest of pickling and fresh-market cucumbers. Cucurbit Genet.
Coop. Rpt. 7:35-36.
Contribution No. 1903-E, 1986 series, from the Agricultural Research Organization,
Bet Dagan, Israel.
