Breeding Cucumbers for Fresh-market Production in Egypt

Cucurbit Genetics Cooperative Report 13:12-13 (article 5) 1990

Mahdy I. Metwally and Todd C. Wehner
Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695-7609
(Dr. Metwally is a Visiting Scientist, Kafr El-Sheikh, Tanta Univ., Egypt)

One major cultivar of cucumber is grown for field production in Egypt, ‘Beta Alpha’ (referred to as ‘Beit Alpha’ in the U.S.). The cultivar is preferred for its fruit characteristics. Both the monoecious and gynoecious hybrids are grown, as well as the monoecious open-pollinated type. The U.S., Netherlands, Denmark, and England are the major suppliers of seed. The cultivated area is 18, 730 ha/year, with an average yield of 9.5 Mg/ha.

In the last 3 years downy mildew (Pseudoperonospora cubensis) eliminated most of the crop, with losses of 80 to 100%. New mildew-resistant cultivars have been introduced in the last few years, i.e. ‘Amra II’ from U.S. (Petoseed) and ‘Sweet Crunch’ from Japan. These hybrids are moderately resistant to downy mildew, and have the proper fruit type. For plastic tunnels (small greenhouses), many hybrids are available with the usual higher cost for seed.

Disease and insect problems. The major diseases of cucumber are (in order of importance) downy mildew, cucumber mosaic virus, powdery mildew (Sphaerotheca fuliginea), fusarium wilt (Fusarium oxysporum f. sp. cucumerinum), and gummy stem blight (Didymella bryoniae). Downy mildew is by far the major disease, and is capable of eliminating the crop, even with a weekly spray program. Cujcumbers are affected by many insects, but aphid (Aphis gossypii) is the most important. Breeding for resistance to Egyptian disease problems is urgently needed in order to reduce the pesticide requirement for cucumber production.

Cultural practices. Cucumber is grown in 2 seasons, summer (sown 20 February to 7 April) and fall (sown 10 to 20 July). In plastic houses, cucumber is sown from 1 September to 7 October. Row spacing is 1 m with spacing of 20 to 30 cm between hills, with 4 seeds per hill. Seed are sown by hand, at a rate of 3.6 kg/ha. Two weeks after sowing, hills are thinned to 2 plants. Cucumber is intercropped in the summer with tomato or cowpea. In the fall season, cucumber is intercropped with tomato.

Fruits are harvested every two days (about 15 harvests) 60 to 70 days after sowing. The ideal fruit has light-green skin color, uniform green ( gene) and wartless (t gene). Fruit dimensions at harvest are 12 to 15 cm long and 30 to 35 mm diameter, with a weight of 100 to 120 g.

Table 1. Monthly mean air temperature and relative humidity (%) in 1989z.

Temperature (C)

R.H. (%)

Season

Month

Max.
Min.
Aver.
Max.
Min.
Aver.
Winter Dec. 18.9 7.9 13.4 78.1 74.9 76.5
Jan. 20.6 8.9 14.8 73.0 71.0 72.0
Feb. 19.7 6.0 12.9 76.0 72.0 74.0
Spring March 22.0 9.4 15.7 73.8 73.6 73.7
April 30.0 12.1 21.5 70.0 65.1 67.6
May 31.5 14.3 22.9 64.5 57.8 61.2
Summer June 34.3 19.0 26.7 58.7 61.7 60.2
July 34.4 21.5 28.0 74.6 72.8 73.6
August 32.8 20.5 26.7 75.3 73.9 74.6
Autumn Sept. 31.8 18.6 25.2 78.0 76.3 77.2
Oct. 28.2 14.5 21.4 72.1 76.7 73.4
Nov. 23.1 9.5 16.3 69.6 67.4 68.5

zSource: SAKHA Agriculture Research Station, KAFR EL-SHEIKH Governorate.