Cucurbit Genetics Cooperative Report 1:11 (article 8) 1978
Fasciation in the Cucumber
R. W. Robinson
New York Agricultural Experiment Station, Geneva, NY 14456
Fasciated plants with wide, flattened stems and increased numbers of leaves, tendrils, and flowers per node, frequently occur in the cucumber cultivar 'Lemon' and other andromonoecious cucumber cultivars. Fasciation is associated with opposite leaf arrangement at lower nodes of the main stem. Leaves are borne in decussate arrangement for several nodes on normal appearing stems, then phyllotaxis abruptly changes, leaf arrangement thereafter being alternate and some plants develop a fasciated stem.
Fasciation is recessive; reciprocal crosses between fasciated and normal plants produced only normal plants in the F1. The ratio of fasciated to normal plants varied significantly in different F2 populations. Although available genetic evidence is not definitive, it appears reasonable that fasciation is conditioned by a single recessive gene with incomplete penetrance. Genic background likely influences penetrance and expression of the fasciation gene, accounting for the different proportion and degree of fasciation manifested in the F2 of different crosses. Environmental factors also influence penetrance of the fasciation gene; the proportion of fasciated plants of 'Lemon' was increased by irradiation and growth regulator treatments, but these treatments did not induce fasciation in normal monoecious cultivars.