Application of the Electrophoretic Isozyme Method to Muskmelon Breeding

In order to explore the possibility of application of isozyme analysis to melon breeding, several enzymes of melon seedlings were studied using the polyacrylamide gel isoelectrofocusing technique. The plants examined included 10 cultivars of 3 botanical varieties and 3 F1 hybrids between them.As to the zymograms of glutamate dehydrogenase, malate dehydrogenase, and esterase, there was no significant difference among cultivars. In the peroxidase isozymes there was a slight difference in zymograms between powdery mildew resistant cultivars and susceptible ones : that is, the former had 22 bands and the latter 21 bands. In the acid phosphatase isozymes remarkable differences in banding patterns expressed by optical density were shown not only among varieties, but also within a variety, that is, between the American type and the British one in var. reticulatus. It is concluded that acid phosphatase isozymes seem useful for the discrimination of varietal differences among plants, and accordingly it may be applied to the selection in melon breeding.