Abstract
Yearly fluctuations of two types of fruit cracking of so-called“Hetasuki”and “Kachorekka”, which occur at the calyx end and the stylar end, respectively, were studied in clones from seedling populations of Japanese persimmon (Diospyros kaki Thunb.). Fruits were rated for the degree of cracking using a scale of 0 to 10 (0=none, 10=severe). The greater the mean values of indices in 3 or 5 years of evaluations, the larger the yearly fluctuations in the cracking indices became. The interaction of genotype and year in cracking indices was very large. Progenies which bear fruit with severe cracking even in one year can be removed earlier in the breeding program, because they have the genetic property of a high degree of cracking. On the contrary, rather long-term evaluations are necessary for the selection of promising progenies with little or no fruit cracking.
