Realisation of New Variability by Means of Inbreeding in Some Indigenous Red Grapevine Cultivar of Verona (North East Italy)

Corvina, Corvinone and Rondinella, the three main grape varieties cultivated in Verona, are characterized by a high phenotypic homogeneity. Self-pollination has been used to give expression to the intrinsic variability present in the genome of these varieties. The experimental vineyard located in Verona shelters, besides the seedlings of each variety, some cuttings obtained from the seedlings mother plants. The genotypes under examination are 357 for Corvina, 341 for Rondinella and 294 for Corvinone. 30 O.I.V. descriptors, phillometry, anthocyanin profile and AFLP were used to characterize each genotype. Frequency distribution of mother plants and seedlings populations were compared and results show that increase of variability was achieved. The genetic basis of the normal distribution curve of the three inbred populations is always larger than that one of the cuttings. Recombination of the characters brings to genotypes extremely different from the mother plants but always in a very low number. As a matter of fact, most of the seedlings are similar among themselves and do not discriminate from the mother plants using ampelographical methods. Only AFLP analysis shows differences between some seedlings and mother plants. Results confirm the hypothesis of policlonal origin of some cultivars as suggested by Rives (1961). Self-pollination opens up interesting prospects for the genetical improvement of grapevine