W. Lange et al., VIRULENCE IN THE BEET CYST-NEMATODE (HETERODERA-SCHACHTII) VERSUS SOME ALIEN GENES FOR RESISTANCE IN BEET, Fundamental and applied nematology, 16(5), 1993, pp. 447-454
Three populations of the beet cyst nematode (BCN), Heterodera schachti
i, were used in resistance tests with various plant materials of the g
enus Beta. Population 129-SB had been selected for virulence to gene(s
) for resistance obtained from chromosome pro- 1 of B. procumbens and
is considered to be a new pathotype of this nematode species. In addit
ion, an unselected sib population (129-FR) and the wild-type populatio
n BCN-WA were used. The wild species B. procumbens and B. patellaris s
howed nearly complete resistance to all three nematode populations. Po
pulation 129-SB was able to produce cysts on the two breeding stocks o
f sugar beet (B. vulgaris subsp. vulgaris), with resistance from chrom
osome pro-1. However, the mean number of cysts per plant was significa
ntly less than on the susceptible control cv. Regina. Nematode populat
ion 129-SB also was able to break the resistance from chromosome pat-1
of B. patellaris, when present as a monotelosomic addition. The monos
omic addition carrying chromosome pro-7 of B. procumbens and the parti
ally resistant accession BMH of the wild sea beet (B. vulgaris subsp.
maritima) showed resistance in tests with all three nematode populatio
ns, but population BCN-WA produced significantly more cysts on the sus
ceptible plants and on BMH than the other two populations. These diffe
rences indicate variation in the nematode populations for fitness and
perhaps also for virulence. It is proposed to modify the nomenclatural
system for the naming of the postulated genes for resistance to H. sc
hachtii on the chromosomes pro-1, pat-1 and pro-7, and to name them Hs
1 pro-1, Hs(pat-1), and Hs2 pro-7, respectively.