EXPERIENCE IN PRE-BREEDING FOR QUANTITATIVE RESISTANCE TO LATE BLIGHT IN POTATO – A REVIEW

Abstract

ABSTRACT: Pre-breeding for quantitative late blight resistance of potato is variety-breeding in principle, in which foliage and tuber blight resistance take precedence over all other traits; the resistance is utilized from diverse wild potato clones. A broad basis of very different pre-bree­ding clones is bred and retained as cross parents for crossing resistant x resistant. Progress in re-establishing of genome for cultural traits and preserving of high level of polygenic deter­mined late blight resistance at the same time requires consideration of all traits, combination breeding for these and minimi­zing of backcrosses. Results are given mainly for particular difficult combining with early maturity in long-day conditions and for applied selection system.

Vertical di­stan­ce of AUDPC to linear re­gression line with matu­rity is a correct criterion of true quantitative foliage-blight resistance in long-day condition. Slow progress in combining of polygenic determined traits is shown. Breeding strategy is explained and problems are dis­cussed, solutions are indicated. That pre-breeding is a very difficult bree­ding task, requiring hig­hest le­vel of special experience and a stable very long-term con­cept in public control. Saving of one third of current oomycide application is at least expected by new varieties.