TO THE HISTORY OF BREEDING FOR LATE BLIGHT RESISTANCE IN POTATO UP TO 1960IES – A REVIEW

Abstract

ABSTRACT: The dra­matic appearance of late blight in Europe in 1845 and the follo­w­ing years gave a push for developing of plant pathology and potato breeding. Variety Cham­pion was a milestone in the early histo­ry of breeding for quantitative blight resistance, determined by polygenes. Private bree­ders selected lowest blighted clones in field conditions from gene pool of cultural potato. The insufficient re­sults then achieved are underestimated today.

Detection of simple inherited late blight resistance as qualitative trait in wild potato ma­terial followed inten­sive phytopathological and bree­ding work in public financed insti­tutes. Expeditions to South and Middle America re­sulted in establishing of gene banks for potato species, increased knowledge of it including their blight resistance and other traits and its use in breeding. Interspecific hybrids included mainly S. demissum as source of resistance and were used to breed varieties with R-genes released after 1930. Exam­ples of parentages are given. Oc­cur­rence of ra­ces of P. infestans could be identified since 1932 by differentials pos­ses­­sing different dominant R-genes. Now one could distinguish between qua­li­tative (R-gene coded hyper­sen­sitivity) and quantitative resis­tan­ce. Laboratory methods of assessment of resistance were de­ve­loped mainly on foliage, but also on tubers and were applied in large scale. Quicker develop­ment of new virulent races than breeding could counteract with new resistant cultivars finished use of race-depended type of resis­tan­ce after 1960ies. Application of oomycides became the main measure of protec­tion.