SUTDIES ON THE CORN CYST NEMATODE (CCN) HETERODERA ZEAE INEGYPT: IV-VARIATION IN DEVELOPMENT AND REPRODUCTION OF FOUR DIFFERENT POPULATIONS ON SOME CORN CULTIVARS

Abstract

Four populations of the corn cyst nematode, Heterodera zeae – were collected from corn fields in four different counties in Egypt. In a green-house experiment, the development and reproduction of CCN populations on 15 corn cultivars and lines varied greatly. Two populations from Bahtim and Tanta, to some extent, were alike on all plants tested, where they reproduced well. On the other hand, the other 2 populations from Belbais and Giza failed to reproduce on some corn cultivars or lines. By using differentials chosen from those resistant cultivars or lines selecting Giza 2 cultivar, three physiological groups have been separated. Bahtim and Tanta populations could be categorized as one group, whereas each of Belbais and Giza proved to be two additional separate groups.