Estimation of New Tetraploid Apple Forms as Donors of Diploid Gametes for Selection on a Polyploidy Level

The comparative analysis of meiosis in a process of microsporogenesis in a number of new tetraploid apple forms is given. The suitability of these apple forms for the application in breeding on a polyploidy level as donors of diploid gametes have been determined. Forms 25-37-47 (SR0523, 2x X Antonovka ploskaya, 4x) and 30-47-88 (Liberty, 2x X 13-6-106, 4x) are especially valuable as initial forms for breeding, since they give a sufficient amount of the fertile pollen and carry genes of immunity to scab: Form 25-37-47 carries gene V_m and Form 30-47-88 carries gene V_f that is very important for the development of new adaptive and high-qualitative triploid apple cultivars.