Variations in the sugar, organic acid, and amino acid composition of table grape berries were determined in three successive years in 129 grape cultivars. Three regional groups were represented among these cultivars; European, North American, and Japanese. All cultivars are conserved at the Fukuoka Agricultural Research Center in Japan. Three representative ripe average-sized bunches were selected from one vine per cultivar. Ripeness was judged by visual observation of seed color change to dark brown, without senescence of berry tissue. Soluble solids content (SSC) was weakly correlated with other berry traits, but strongly correlated with total sugar content. Genotypic variance (r g 2 ) was significant for all berry traits, especially for a ratio (sugar composition) and c ratio (amino acid composition). The yearly effect (r y 2 ) was significant for SSC, total sugar content, and total amino acid content but not for a ratio, titratable acidity, b ratio (organic acid composition) and c ratio. Repeatabilities over the 3 years were very high for a ratio and c ratio, while they were low for SSC, total sugar content, titratable acidity, b ratio, and amino acid content. Correlation coefficients between the values of each individual year and the 3-year mean were relatively high for the a ratio and c ratio. We highlight the varietal differences in the a ratio and c ratio because of the low environmental variation. Two types of grape were distinguished on the basis of sugar composition: hexose accumulators (a ratio C 0.81) and sucrose accumulators (a ratio B 0.80). The hexose-and sucrose-accumulating traits were related to genetic or regional differences. Cultivars were classified into five types on the basis of the c ratio. Like the a ratio, variation in the c ratio is closely related to cultivar parentage and regional differences. Vitis vinifera cultivars exhibited a skewed distribution with a c ratio below 1.0 because they contain low levels of sweet amino acids. In contrast, the c ratio frequently exceeded 1.5 in American hybrid cultivars because they contain high levels of sweet amino acids.

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We estimated genetic and environmental variance components for fruit quality traits (cluster weight, berry weight, soluble solids content, total sugar content, sugar composition, free acid content, total amino acid content, amino acid composition), and a functional trait (gamma-aminobutyric acid (GABA) content) of three commercial tetraploid table grape cultivars (Kyoho, Pione, Suiho) grown in Japan over three successive years. ANOVA showed that the effect of genotype was significant (P \ 0.05) for all traits except soluble solids content and total sugar content. The effect of the year was significant for all traits except amino acid composition (c ratio) and GABA content. The variance of genotype (r g 2 ) was highest for c ratio (63.6%), high in sugar composition (a ratio, 60.3%) and GABA content (58.8%), and negligible for soluble solids content (0.0%) and total sugar content (0.0%). The variance of among years (r y 2 ) was very high in soluble solids content (82.8%), high in total sugar content (60.2%) and negligibly small in c ratio (8.7%) and GABA content (6.4%). Some effects of genotype 9 year interaction, among vines within genotypes, and vine 9 year interaction were statistically significant, but these components were negligibly small. Except for soluble solids content and total sugar content, significant varietal differences in the traits were recorded. Variance estimates for each trait provides useful information for optimal yearly repetition to effectively discriminate genetic differences in fruit quality and functional traits for improving future tetraploid table grape breeding programs.

The ability of grape cultivars to produce resveratrol in response to UV radiation is associated with their resistance to fungal pathogens. In this study, we evaluated the UV-induced resveratrol production potential of grape flowers and green berries of 72 grape genotypes. Their ability to produce resveratrol in response to UV radiation was used to establish a selection criterion for screening genotypes for resistance to gray mold and powdery mildew. We quantified resveratrol in grape flower extracts from pre-bloom and early bloom flowers after exposure to UV radiation. There was a strong negative correlation between UV-induced resveratrol production and susceptibility to Botrytis infection. The grape genotype was considered to be susceptible to gray mold when the resveratrol content of whole flower clusters was less than 10 lg g -1 FW after the UV treatment. We determined resveratrol production in response to UV radiation in whole grape berries from 0 to 30 days after full bloom. The ability to produce resveratrol in response to UV increased by 8-to 20-times during this period, depending on the genotype. At 30 days after full bloom, Vitis vinifera genotypes generally had low levels of resveratrol (\50 lg g -1 FW), while interspecific hybrids, especially the North American cultivars, had high levels ([50 lg g -1 FW). There were clear varietal differences in resistance to Erysiphe (powdery mildew) infection. Susceptibility to Erysiphe infection was strongly negatively correlated with UV-induced resveratrol production.

Chromosome doubling with colchicine treatment of seedlings derived from cross among hexaploid persimmons (Diospyros kaki Thunb.) were carried out to induce dodecaploid persimmons. Colchicine treatment of the meristem of seedlings in vitro was effective at a concentration of 0.03-0.05% for 12-24 hours. Induced dodecaploid seedlings generally showed weak vigor, but some vigorous seedlings could be obtained. Compared with the hexaploid parent cultivar, these dodecaploid seedlings had longer stomatal guard cells and lower stomatal densities. Although the rate of flower bud on dodecaploid seedlings was lower than that of the hexaploid seedling, some of the seedlings bore both pistillate and staminate flowers. Since the pollen of the induced dodecaploid seedlings has germination ability, the seedlings could be parental stocks for the breeding of seedless-PCNA persimmons.