Possibility of Natural Hybridization between Cyperus iria L. and Cyperus microiria Steud.

Abstract

No experimental evidence of hybridization between Cyperus iria L. and C. microiria Steud. has heretofore been documented, though occurrence of natural interspecific hybrids in the genus Cyperus has been reported by Koyama (1953, 1961). The authors have obtained new types of plants from an experimental field after a mixed planting of these two species. The new plants showed an intermediate form between the two in shape of floral scale and floret density. They were longer in spikelet length and had a greater number of florets, though seed fertilities were evidently lower than those of the parent species. The seeds of new plants were dormant in each of the reciprocal crossings between C. iria and C. microiria, and the dormancy could be broken by a stratification at 15°C for one month. This character was considered to have been inherited from the dormant parent C. microiria. Progenies of the new type plants also showed a clear segregation in the characters of spikelet and floret morphology. It can thus be confirmed that these plants obtained from mixed planting in the experimental field are to hybrids between C. iria and C. microiria.