Fagaceae

Abstract

This develops small unisexual flowers with both the sexes on the same tree or bush. Spontaneously arisen mst occurs in Japanese chestnut (C. crenata), American chestnut (C. dentata) Chinese chestnut (C. mollissima) Chinquapin (C. pumila) and C. sativa (this Vol.). In these, the anthers are rudimentary and lack PMC’s. Genetic control of the sterility is not known, but the action of ms or fr genes is evident (Table 24.1). Jaynes (1963) reported failure of staminate primordia to develop anthers in some C. mollissima, C. sativa and many chestnut hybrid trees. Their female fertility was normal. Although the exact cause and control of sterility are not known, the sterility in the species is probably genetic or physiological, as only a few trees (one to three) out of a huge stand exhibited sterility, others growing side by side being perfectly normal. Omura and Akihama (1980) found mst plants in clones and cultivars of Castanea crenata, C. mollissima, C. sativa, C. sequinii and their interspecific hybrids. The sterility was manifested as: (i) antherless florets (ii) premature male floret fall and (iii) nonviable pollen. Some F₁ plants of C. crenata X C. sativa are also mst, as their florets develop staminodes.