High levels of resistance against
Meloidogyne hapla have been identified in wild species of tuber-bearing potatoes, but only QTL with partial effects have been identified so
far in back crosses with cultivated potato. This study was designed to test if pyramiding of two previously identified resistance
genes,
R
Mh-tar
and
R
Mh-chc
A, will result in improved or even an absolute level of resistance.
R
Mh-tar
and
R
Mh-chc
A introgressed from the wild tuber-bearing potato species
Solanum tarijense and
Solanum chacoense were combined in a segregating diploid
Solanum tuberosum population. With the aid of AFLP markers, descendants from this segregating population were classified into four groups,
carrying no
R gene, with only
R
Mh-tar
, with only
R
Mh-chc
A and a group with the pyramided
R
Mh-tar
and
R
Mh-chc
A. Upon inoculation with
M. hapla isolate Bovensmilde, the group containing only
R
Mh-chc
A showed a decline of 88% in average number of developed egg masses compared to the group without
R
Mh-chc
A and
R
Mh-tar
. The group of genotypes containing only
R
Mh-tar
, but not
R
Mh-chc
A, showed a decline of 55% in the number of developed egg masses compared to the group without
R
Mh-chc
A and
R
Mh-tar
. Unfortunately, the latter effect of
R
Mh-tar
was not significant. The effect of both loci,
R
Mh-tar
and
R
Mh-chc
A combined, did not further reduce the number of egg masses compared to the level of
R
Mh-chc
A alone.
相似文献