Anthracnose Resistance of the Cucumber Germplasm Collection in North Carolina Field Tests

Abstract

The resistance of the entire cucumber (Cucurnis sativus L.) germplasm collection within the U.S. National Plant Germplasm System and of many available cultigens (improved cultivars, breeding lines, land races, feral cucumbers, and plant introductions) to anthracnose [Colletotrichum orbiculare (Berk. and Mont.) Arx] was tested under field conditions in North Carolina and compared with known resistant cultigens. Mean anthracnose leaf ratings for environments ranged from 5.5 to 7.7. Data within an environment were standardized to a mean of 4.5 and a standard deviation of 1 to improve comparisons among cultigens by removing the main effect of environments. The moot resistant 27 cultigens are all of U.S. origin and are improved cultivars or breeding lines. The most resistant cultigens, for which multiple environment data are available, were ‘Dual’, ‘Regal’, ‘Slice’, and Gy 3. The most susceptible cultigens, for which multiplenvironment data are available, were PI 390248, PI 251028, and PI 277741. Thirty‐one cultigens were classified resistant, 100 moderately resistant, and 773 susceptible. No plant introductions were found to be more resistant than the most resistant named cultivars or breeding lines tested. Cultigens found to be resistant in other studies were generally moderately resistant or resistant in this study, except for PI 179676 and PI 183445, which were susceptible in this test.