III. VULNERABILITY
A. Status and Risks
The level of diversity of available cultivars has been surveyed. Data indicate that many cucumber
cultivars grown in the U.S. are similar in parentage. Many of the pickling cucumber hybrids have
Gy 14 as a significant source of germplasm in the seed parent. There is also much usage of 'Sumter'
and M 21 in the germplasm of the pollen parent. The same is true of fresh-market cucumbers, where
much use is made of 'Marketmore' and 'Poinsett', either directly or as a component of a hybrid.
The uniformity of cucumber cultivars represents a risk to the country if new, virulent diseases or
insects appear in the production areas. The same is true if new, or existing environmental stresses
become more important. For example, many cucumber cultivars have disease resistance which comes
from the same genetic source as other cultivars. New races that can overcome resistance in one Cucurbit Germplasm Committee Report: Cucumber; Updated 1996 6
cultivar would then cause the loss of all similar cultivars. However, resistance to some diseases (e.g.,
scab, CMV and powdery mildew) has held up for decades.