COMPARISON OF FRUIT TRAITS BETWEEN POLLINATION CONSTANT NON-ASTRINGENT (PCNA) AND NON-PCNA OFFSPRING DERIVED FROM TWO BACKCROSSES (NON-PCNA × PCNA) × PCNA

The National Agriculture and Food Research Organization Institute of Fruit Tree Science (NIFTS) persimmon breeding program in Japan has been conducted with an emphasis on releasing new pollination constant non-astringent (PCNA) cultivars since PCNA is the most desirable fruit character because of the stable natural astringency loss on the tree. However, PCNA is a recessive trait, and its genetic resources are very limited, furthermore repeated crossing within the narrow gene pool leads to inbreeding. Therefore, a strategy for generating PCNA offspring through the backcross [(non-PCNA × PCNA) × PCNA] has been conducted since 1990. ‘Taigetsu’ and ‘Taiten’ are non-PCNA F₁ cultivars resulted from a cross between non-PCNA and PCNA. We compared fruit traits between PCNA and non-PCNA offspring derived from two backcrosses ‘Taigetsu’ or ‘Taiten’ × PCNA (‘Kanshu’). Mean fruit weight was significantly lower in PCNA offspring than in non-PCNA offspring in both backcrosses. Cracking at the fruit apex occurred more frequently in PCNA offspring than in non-PCNA offspring fruits, whereas there was no significant difference in cracking at the calyx end and in fruit ripening time. Thus, the PCNA trait influenced on fruit weight and cracking at the fruit apex in the backcross offspring.