Biotechnology and apple breeding in Japan

Abstract

Apple is a fruit crop of significant economic importance, and breeders world wide continue to develop novel cultivars with improved characteristics. The lengthy juvenile period and the large field space required to grow apple populations have imposed major limitations on breeding. Various molecular biological techniques have been employed to make apple breeding easier. Transgenic technology has facilitated the development of apples with resistance to fungal or bacterial diseases, improved fruit quality, or root stocks with better rooting or dwarfing ability. DNA markers for disease resistance (scab, powdery mildew, fire-blight, Alternaria blotch) and fruit skin color have also been developed, and marker-assisted selection (MAS) has been employed in breeding programs. In the last decade, genomic sequences and chromosome maps of various cultivars have become available, allowing the development of large SNP arrays, enabling efficient QTL mapping and genomic selection (GS). In recent years, new technologies for genetic improvement, such as trans-grafting, virus vectors, and genome-editing, have emerged. Using these techniques, no foreign genes are present in the final product, and some of them show considerable promise for application to apple breeding.

IN VITRO REGENERATION AND TRANSFORMATION OF APPLE (Malus domestica Borkh.) ROOTSTOCK MALLING 7 USING RICE CHITINASE GENE

“…So there is an urgent need to adopt modern biotechnological tools which could help to accelerate this process. Plant genetic transformation using desirable genes has geared up and facilitated various apple crop improvement activities by targeting resistance to fungal or bacterial diseases, improved fruit quality, or root stocks with better rooting or dwarfing ability (Igarashi et al, 2016). Among fruit crops, domesticated apple attains the distinctiveness because of the availability of a wide range of clonal rootstocks, thereby permitting the development of a 'designer tree size' appropriate for high density plantations.…”

A New Plant Breeding Technique Using ALSV Vectors to Shorten the Breeding Periods of Fruit Trees

“…even more [3,51,[55][56][57][58][59]. The combination of virus-induced flowering technology described here with information obtained from these research is expected to lead to further optimization of fruit tree breeding in the future.…”

“…The long juvenile phase of fruit trees is a significant barrier for efficient fruit tree breeding [3,51]. The technology developed in the present study substantially shortens one generation of fruit trees via infection of the trees with an ALSV vector for promotion of flowering in fruit tree breeding.…”

Practical DNA markers to Estimate Apple (Malus x domestica Borkh.) Skin Color, Ethylene Production and Pathogen Resistance

“…This is why DNA markers which are genetically linked to agriculturally important traits are developed in many crops, including apple. By using DNA markers, breeders can select promising cultivars at the juvenile phase, then further estimate these restricted number of plants in the second round of screening [3].…”