Apple breeding programs and methods, their development and improvement

It is shown that the long-term studies of some features of apple development allowed breeding intensification and reduction of cultivar development time from 36–48 to 23–27 or even 13–17 years. It is noted that requirements for new cultivars are constantly becoming tougher. They include high fitness, early maturation, performance, large size of fruit (140–160 g), thin and firm skin without rust signs or waxing, absence of abscission, sugar content of no less than 12%, ascorbic acid content of about 30 mg/100 g, and preservation capacity of winter varieties of no less than 7–8 months (Kichina, 2011). It is hardly possible to create a perfect cultivar, because requirements for new cultivars change fast and do not cover the time required for breeding. Nevertheless, we should aspire to it. As a result of long-term breeding for the improvement of fruit biochemical composition, we managed to raise cultivars with high contents of P-active substances (to 400–600 mg/100 g), but cultivars with the desirable content of ascorbic acid (25–30 mg/100 g) have not been developed. A number of cultivars resistant to scab (bearing V f gene) have been developed in Russia. However, it is in prospect to develop cultivars on the digenic base with higher resistance combining genes V f and V r , V f and V m , etc. It is necessary to create cultivars having immunity or high resistance to powdery mildew, as well as European red mite, apple moth, and other pests. Cultivars with complex resistance to diseases and pests are needed. Apple breeding on a polyploidy level at the Institute of Fruit Crop Breeding turned out to be quite promising. For the first time in Russia, triploid apple cultivars were obtained from different chromosome crossings 2x × 4x and 4x × 2x. They are distinct owing to more regular fruit bearing, high marketability of fruits, and increased autogamy. This division of breeding should be developed in the future. Columnar apples developed at the Technological Institute of Horticulture and Nursery Garden, the Michurin All-Russia Research and Development Institute of Fruit Crop Genetics and Selection, and the Institute of Fruit Crop Breeding, as well as other research institutions, are of interest for fruit-growing intensification. They are valuable in amateur gardens, first of all. Breeders will have to develop columnar, scab-resistant, and triploid cultivars with a high quality of fruit. Prospective is breeding aimed at developing varieties for true-rooted and autogamous cultivars using apetalous plants. With regard to global climate warming, it may be necessary to revise the range of already existing apple cultivars and directions in breeding.