Comparative Ease of Pellicle Removal among Japanese Chestnut (Castanea crenata Sieb. et Zucc.) and Chinese Chestnut (C. mollissima Blume) and Their Hybrids.

Abstract

A genetic analysis on the ease of pellicle removal from kernels of Japanese and Chinese chestnuts and their interspecific hybrids and their Fi progenies was attempted by using the null hypothesis test. Trees from several inbred and crossbred lines involving up to 200 selections grown at the Fruit Tree Research Station at Tsukuba were used for this study.1. The ease of peeling the pellicle of nuts on interspecific hybrid progenies (F1) was found to be influenced by the pollen parent. The pellicle of the nuts set on the selections by pollination with Chinese chestnut pollen was easy to remove, whereas that of nuts on the same selection was difficult to remove if they were set by pollen from a Japanese chestnut tree. However, the pellicle of nuts set on selection '366-2', a progeny of '68-6' ('Houji-360'×'Toyotamawase') ×'Hayashiamaguri', by pollen of the Japanese chestnut, 'Tsukuba', was easy to peel.2. Using the null hypothesis test, the hybrid selections were classified into 6 types : Selections which yielded nuts which peeled easily like those of the Chinese species were classified as Type E. Selections which yielded nuts which were difficult to peel like the Japanese chestnut were classified as Type D. Selections which yielded nuts which were intermediate between Type E and Type D, were put into Type I. Selections that yielded nuts which ranged in peeling characteristics from E to D were subdivided into Types; S1, S2 and S3, these, are called metaxenia.3. Selections classified as Type E were found to be in lines of cross combination of sibling among Fi and back-crossing with Chinese cultivars. On the other hand, no all progenies of Chinese chestnuts were easy to peel. All progenies with easily removable pellicles were derivatives of the Chinese chestnut cultivars, 'Houji-360' or 'Houji-480' as a male or female parent, in their pedigrees. These data provide a genetic basis for using cross combinations for chestnut breeding in the future.