抄録
The phylogenetic relationship of ten crops selected from all the seven tribes of the Gramineae which contain crop species, i.e., wheat, rye and barley from Triticeae, oats from Agrosteae, finger millet from Chlorideae, foxtail millet from Paniceae, sorghum from Andropogoneae, maize and job′s tears from Maydeae, and rice from Oryzeae, were studied by restriction endonuclease analysis of their chloroplast (ct) DNAs. Three enzymes, KpnI, PstI and SalI which are known to give rise to fewer restriction fragments from the cereal ctDNAs than other enzymes were used. For each restriction fragment pattern, the copy number and molecular size of the individual fragments were estimated. From these data, genetic distance (p) between chloroplast genomes of the ten cereals were calculated using Engels′ formula (Engels 1981), based on which their phylogenetic tree was constructed by the UPGMA method of Sneath and Sokal (1973). This phylogenetic tree is in complete agreement with that made from ordinary systematic studies (Tateoka 1957), except for one point, i.e., the genetic distance between the chloroplast genomes of sorghum and maize or job′s tears which belong to different tribes is closer than that between maize and job′s tears which belong to the same tribe. Thus, the two genera, Zea and Coix appear to be better placed in separate tribes. The critical p value to separate two taxa into different tribes, subfamilies and families was about p=0.02, 0.05 and 0.12, respectively.
