Resistance evaluation of sugar beet cultivars to beet cyst nematode under in vitro conditions

The aim of this study was to optimize the in vitro condition for sugar beet cultivation, its possible contamination with Heterodera schachtii, and also to identify susceptible and resistant cultivars to cyst nematode in a sterile plant culture medium. Seeds of a susceptible cultivar named Jolgeh and three resistant cultivars namely Pauletta, Sanetta and Nemakil were cultured on water-agar medium and then transferred to modified Knop medium after germination. Two weeks after germination, roots of each seedling were inoculated with 200 H. schachtii second-stage juveniles (J2s), and after one, two, four, and eight days after inoculation, roots were stained with Fuchsin acid and J2s number were counted. Number of J2s on 16 and 20 days after inoculation were counted as well. Results showed the highest rate of J2 penetration on 4th day and also significant difference between susceptible and resistant cultivars in terms of J2 number. Twenty days after inoculation, an average of 7.17 J2 were found on the roots of Jolgeh, 2.5 on Paulta, one on Sanetta cultivar and 1.2 on Nemakil. According to the results, the method applied in this study can be used as an easy and accurate method to evaluate sugar beet cultivar resistance to cyst nematode.