Development of aneuploid cultivars of dwarf apples

为了培育矮化优质苹果的非整倍体品种，本研究以日本苹果的主要栽培品种--三倍体（3x）和二倍体（2x）品种为材料，通过正反交培育出了幼苗，并对其树体大小、结果情况和果实性状进行了研究.播后10年的杂交花苗率和结实率，2 × 3x均明显优于3 × 2x，但低于2 × 2x，差异均为上级。播种后11年的苗木干围以2x × 2x最粗，2x × 3x中等，3x × 2x最小.对2x × 3x和2x × 2x实生苗成熟果实的性状进行了比较研究。推测2x × 3x和2x × 2x的果皮颜色没有显著差异。结果表明，2x × 3x可分为大小与2x × 2x相当的杂交组合和较小的组合。果实硬度、糖度、酸度和可溶性固酸比也因杂交组合不同而不同。然而，所有这些组合都表现出26.3- 47.8%的可溶性固/酸比，属于食用苹果品种的范围。因此，2x × 3x的实生苗是较好的育种材料.在2x × 3x的‘富士’ב乔纳金’杂交后代中，发现一株果实性状优良的实生苗（暂定名为4FJ 1）。该类型实生苗表现出矮化结实的趋势，其体细胞染色体数目尚不能确定，杂交苗4FJ 1最大的特点是“酸甜”味，极有可能是一个新品种。

In order to develop aneuploid cultivars of dwarf and excellent-quality apples, we grew seedlings from reciprocal crosses between triploid (3x) and diploid (2x) cultivars, leading apple cultivars in Japan, to perform an examination focusing on the tree size, fruiting, and fruit characteristics.1. In both percentages of flowered cross seedlings and fruited ones 10 years after sowing, 2x X 3x was clearly superior to 3x X 2x but inferior to 2x X 2x. For the trunk circumference of seedlings 11 years after sowing, 2x X 2x was the thickest, 2x X 3x was middle-sized and 3x X 2x was the smallest in size.2. Comparative examination was performed on characteristics of matured fruits in 2x X 3x and 2x X 2x seedlings. It is presumed that there is no significant difference in pericarp color between 2x X 3x and 2x X 2x. For fruit sizes, 2x X 3x was found to be classified into cross combination being equivalent to 2x X 2x in size and other combinations of smaller size. Also for fruit firmness, Brix, acidity and soluble solid/acid ratio, 2x X 3x showed differences depending on cross combinations. However, all of these combinations exhibited a soluble solid/acid ratio of 26.3- 47.8%, falling within the range of table apple cultivars. Therefore, it was found that seedlings of 2x X 3x were good as materials for actual breeding.3. Among cross seedlings from 'Fuji' X 'Jonagold' of 2x X 3x, we could find a seedling that had excellent fruit characteristics (4FJ1 as provisory name). For this type of seedling, the tree showed a trend of dwarfness and fruitfulness.The chromosome number in a somatic cell of this seedling could not be confirmed.The greatest feature of cross seedling 4FJ1 is its 'sweet and acid' taste and it is most likely to be a new cultivar.