Kenji Ureshino

Appearance of albino seedlings and ptDNA inheritance in interspecific hybrids of azalea

PCR-RFLP analysis was conducted to clarify the relationship between the leaf color of progenies and their ptDNA inheritance in interspecific three-way crosses, (Rhododendron kiusianum × R. eriocarpum) × R. japonicum f. flavum. All albino progenies contained maternal ptDNA, whereas green and pale-green progenies contained paternal ptDNA. Sectorial chimeric progenies, of which the leaf and shoot color was turned from green to albino during the culture, contained both maternal and paternal ptDNA in green segments and maternal ptDNA in albino segments. These results suggest that albino progenies are caused by the incompatibility between plastome from F1 hybrids of R. kiusianum × R. eriocarpum and nuclear genome from R. japonicum f. flavum.

Effectiveness of three-way crossing for the breeding of yellow-flowered evergreen azalea

For the purpose of obtaining yellow-flowered evergreen azaleas, single and three-way interspecific crosses between evergreen azaleas and Rhododendron japonicum f. flavum were compared. In single cross, although many seeds were obtained from R. eriocarpum × R. japonicum f. flavum, the seedlings from immature ovule were albino or pale-green plants. They were withered away at acclimation. In R. kiusianum × R. japonicum f. flavum, green seedlings were observed, but number of ovules contained in one capsule was very small. In three-way cross, (R. kiusianum × R. eriocarpum) × R. japonicum f. flavum, many viable seeds were contained in one capsule, and about 15% of the seedlings were green leaf colored. These results suggest that three-way cross is one of the useful breeding methods for creating the new yellow-flowered evergreen azalea. Isozyme analysis revealed that most of seedlings were zygotic origin without distinction of their leaf colors, but some green seedlings indicated the same genotypes as the seed parents. Therefore, it is important to confirm hybridity of the seedlings by isozyme technique.

Phenotypic polymorphism for superoxide dismutase in grape

SummaryMultiple isoforms of superoxide dismutase (SOD) occurred in grape following an electrophoretic analysis of 75 grapevine accessions. Three activity zones were resolved, and were designated as Sod-1, Sod-2 and Sod-3 in order of their anodal electrophoretic mobility. For the banding pattern and staining intensity, no differences were observed in both ploidy level and somatic mutation. From the controlled cross tests among SOD variants, the grape SOD was presumed as a dimeric enzyme. The grapevine accessions examined exhibited a high level of phenotypic diversity which could be separated into 13 groups on the basis of SOD zymogram. A remarkable difference in SOD phenotypes was recognized between the cultivated varieties and the wild species and rootstocks. Furthermore, we discussed the associations between SOD phenotypes and agronomically important features, especially seedlessness and lime-induced chlorosis.