Ribes sanguineum Pursh. as donor of leaf fungal disease resistance in blackcurrant breeding

Breeding of blackcurrants resistant to leaf fungal diseases there was carried out by intersec tional crossing. R. nigrum (Eucoreosma) cultivars were crossed with R. sanguineum (Calobotria). In the interspecific crossing combinations within blackcurrant cultivars and clones, the berry set fluctuated from 14.3 to 62.7%. Cultivars that were linked to apomixes started more germs, but during the first weeks more of them fell down. In all the combinations of interspecific crossings there was a small amount (3.8-8.2) of seeds in berry. Among the inter specific hybrids, the amount of plants resistant to powdery mildew (Sphaerotheca mors-uvae), Septoria leaf spot (Mycosphaerella ribis) and anthracnose (Pseudopeziza ribis) increased sig nificantly. Interspecific R. nigrum × R. sanguineum F 1 -F 2 hybrids most often distinguished themselves by a larger number of berries per cluster in comparison with blackcurrants. Berries were of medium size equal to that in blackcurrant cultivars of standard assortment. Berries of the interspecific hybrids had less seeds. There was no dependence between seed number and berry size