EXPERIENCE IN PRE-BREEDING FOR QUANTITATIVE RESISTANCE TO LATE BLIGHT IN POTATO â€“ A REVIEW
Keywords:late blight, Phytophthora infestans, Solanum species, quantitative resistance, breeding strategy
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-breeÂding 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 deterÂmined late blight resistance at the same time requires consideration of all traits, combination breeding for these and minimiÂzing of backcrosses. Results are given mainly for particular difficult combining with early maturity in long-day conditions and for applied selection system.
Vertical diÂstanÂce of AUDPC to linear reÂgression line with matuÂrity 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 disÂcussed, solutions are indicated. That pre-breeding is a very difficult breeÂding task, requiring higÂhest leÂvel of special experience and a stable very long-term conÂcept in public control. Saving of one third of current oomycide application is at least expected by new varieties.