BREEDING NEW VARIETIES OF ATEMOYA (ANNONA SPP. HYBRIDS)

Breeding and selection in atemoya (Annona spp. hybrids) has been much neglected. Few new cultivars of atemoya have been selected in the past 20 years due to the small population of naturally occurring seedlings. Considerable recent progress has been made in selecting new types, identifying appropriate parents and gaining an understanding of the inheritance of desirable traits in atemoya. Inter-varietal crosses have been made between the best selections of atemoya and the main commercial cultivars such as African Pride, Pink’s Mammoth and Hillary White. Interspecific crosses have also been made between four different species: A. cherimola (cherimoya), A. squamosa (sugar apple), A. reticulata (Bullock’s Heart) and A. diversifolia (Ilama). Some 8 000 breeding lines have been field planted since 1992. An alternative approach to conventional breeding using mutation techniques is also being evaluated. Early results indicate that it may be feasible to produce tetraploids using colchicine applications to juvenile buds. Ten advanced selections are being trialed at six evaluation sites throughout Queensland and northern NSW. The program has successfully developed hybrids with red skin colour and pink internal flesh. Red skin colour may be carried by either a single or double recessive gene. Fruit symmetry, flesh recovery and flavour characteristics of some crosses are excellent. To date, one advanced selection, Maroochy Gold, has been named