Reaction of fodder beet varieties to Meloidogyne incognita based on quantitative and qualitative yield characteristics

This study was conducted to evaluate six fodder beet genotypes for their resistance to infestation under naturally infected root-knot nematode, Meloidogyne incognita during the 2015/2016 and 2016/2017 seasons in Nubaria region, El-Behera Governorate, Egypt. Highly significant differences among the genotypes were detected for all studied traits except for fresh foliage weight. The relative susceptibility to root-knot nematode parameters (gall index, gall size, gall area and damage index) indicated that two fodder beet genotypes Beta Rozsa and Jamon were considered as the best with high yield and resistant reaction to M. incognita; in contrast Starmon genotype had highly susceptible reaction while Jary, Mnro andVorosch genotypes had moderately resistant. Fodder root yield was positively and significantly correlated with root weight; meanwhile, it was negatively and significantly correlated with damage index and gall index, respectively. These findings indicate that selection for root weight and infestation involved in this study affected the variability of root yield. Stepwise multiple regression linear analysis for fodder beet yield showed that root weight per plant, gall index, number of leaves per plant and dry weight per plant were the most important contributing traits to root yield (R^2= 94.76%). Hence, the selection among these traits would be accompanied by high yielding and more effective for the improvement of fodder root yield in the same conditions.