EVALUATION OF SOME SUGAR BEET VARIETIES FOR MELOIDOGYNE INCOGNITA RESISTANCE AS INDUCED BY GAMMA-IRRADIATION

摘要

The main objective of this study was to evaluate the effect of irradiation against 28 varieties of sugar beet seeds with 100Gy gamma-dose for inducing the plant resistance to root-knot nematode, Meloidogyne incognita infection through measuring some morphological parameters, biochemical components, root characteristics and host susceptibility rating. Results of the study cleared that, relative to control plants (non irradiated seeds and soil not infected with nematode), root-knot nematode significantly reduced plants shoot height, number of leaves, leaf area index, root length, root diameter and root weight, while increased the activity of peroxidase and polyphenol oxidase in addition to decrease in the number of juveniles (J(2)) in the soil, and number of galls, gall index, gall size and gall area. However, plants grown from irradiated seeds showed significantly different values between control and infected plants and hence, 100 Gy dose can increase sugar beet tolerance to nematode where, 7 varieties changed from highly susceptible to moderately resistant, one variety changed from highly susceptible to susceptible and 12 varieties changed from susceptible to moderately resistant.