Akira Wakana

Aneuploid plants derived from crosses with triploid grapes through immature seed culture and subsequent embryo culture

Through immature seed culture and subsequent embryo culture, aneuploid plants were derived from various crosses among 184 different triploid hybrid grape vines. In self-pollinations of the 184 vines, 0 to 1.6% of flowers produced immature seeds. In 16 reciprocal crosses between diploid and triploid and between tetraploid and triploid grapes, 0 to 23.0% of flowers produced immature seeds. The immature seeds excised 30–50 days after pollination were cultured for three months on Nitsch and Nitsch medium supplemented with L-glutamine, L-serine, L-cysteine and casein hydrolysate. Embryos developed within the cultured immature seeds were subcultured onto germination medium consisting of MS medium with 1 μM BA. Thirty-four of 137 embryos from 458 immature seeds germinated. Five of the 34 embryos grew normally. The five recovered plants were aneuploids with chromosome numbers from 51 to 59. The rates of embryo and plant recovery were different in different crosses with triploid grapes.

Study of the parentage of grape cultivars by genetic interpretation of GPI-2 and PGM-2 isozymes

SummaryTwo highly variable enzyme systems of glucosephosphate isomerase (GPI) and phosphoglucomutase (PGM) were used to investigate the parentages of grape cultivars. Of 35 parent/offspring combinations that we investigated, 30 combinations gave alleles in the offspring which were presented in the reported parents, whereas 5 combinations gave alleles in the offspring which were not extractable from the reported parents. The Gpi-2 genotype of ‘Hiro Hamburg’ and the Pgm-2 genotype of ‘Pione’ indicated that ‘Koshu Sanjaku’ and ‘Cannon Hall Muscat’ may not have been the paternal parent respectively. The Gpi-2 genotype of ‘New Niagara’ and the Gpi-2 and Pgm-2 genotypes of ‘Beniyamabiko’ indicated that ‘Niagara’ and a hybrid from ‘DxK151’ x ‘Delaware’ may not have been the maternal parent respectively. The Gpi-2 genotype of ‘Cannon Hall Muscat’ grown in Japan indicated that this cultivar may not have originated as a tetraploid sport of ‘Muscat of Alexandria’.