77 



mentioned hypothesis of the descent from a common basic form. Beij- 

 ERINCK expresses this in the foUowing words at the end of his second 

 treatise: "so muss ich anerkennen, dass die Annahme der Herkunft 

 von Triticum diccocum entweder aus einer uralten Culturvarietat von 

 Triticum monococcum oder durch die directe Umwandlung irgend 

 einer Form des wilden Tr. monococcum lasiorrachis, die Hypothese 

 ist, welche mich auf Grund unserer gegenwartigen Kenntnisse weit- 

 aus am Besten befriedigt." 



It is self -evident, that at the present time many of these considera- 

 tions possess historical value only. If one considers the enormous 

 number of facts which the modern investigator has at his disposal in 

 the study of the descent of our cereals (vide E. Schliemann, Ent- 

 stehung der Kulturpflanzen i)), the experimental results and obser- 

 vations that Beijerinck could make use of mean very httle. It is 

 certainly interesting therefore that he has been right in the main. 



First let us state that his observations have been confirmed. Cross- 

 breeding experiments with Tr. monococcum have been repeated. 

 About 30 years after Beijerinck the significance of these cross- 

 breedings f or the solution of the problem has been again recognized ; 

 we refer to the synopsis published by Bleier in 1928 2). These 

 experiments, however, often produced negative results, and whenever 

 that was not the case, the bastards were usually completely sterile, as 

 they were in Beijerinck's experiments. Only Kihara 3) com- 

 municated in 1924 that he had obtained fruit setting after cross- 

 breeding Tr. dicoccum and Tr. monococcum. 



The origin of the cultivated emmer, Tr. dicoccum, has not been 

 completely made clear, notwithstanding the discovery of the wild 

 emmer, Tr. dicoccoides, by Aaronsohn^). If, however, the strong 

 arguments in favour of the latter species as the original wild form of 

 Tr. dicoccum are accepted as conclusive, then one may declare that a 

 common origin of Tr. monococcum and of this Tr. dicoccoides (and 

 therefore also of Tr. dicoccum), from one and the same basic form, is 

 really probable. In the "Schema der Emmer-Ableitung und Ver- 

 breitung", present on page 96 of the above cited work of Schliemann, 

 one finds Tr. aegilopoides mentioned as the common ancestral form of 

 the monococcous and dicoccous wheat series. 



Finally it should be mentioned that Beijerinck's interest in wheat 

 crosses received a new impetus after he became acquainted with 



») Dritter Band des Handbuches der Vererbungswissenschaft, herausgegeben von 

 E. Baur und M. Hartmann, Berlin 1932. 



2) H. Bleier, Zytologische Untersuchungen an seltenen Getreide- und Rüben- 

 bastarden, 5. Intern. Kongr. Vererbungsl., Z. für indukt. Abstamm. u. Vererb. 1. 

 Suppl. 447-452, 1928. 



3) H. Kihara, Cytologische und genetische Studiën bei wichtigen Getreidearten 

 u.s.w. Mem. of the Coll. of Science Kyoto Imper. Univ. Ser. B. 1, 1-200, 1924. 



*) A. Aaronsohn, tFber die in Palastina und Syrien wildwachsend aufgefundenen 

 Getreidearten, Verh. K. K. zool. bot. Ges. Wien .59, 485-509. 1909-1910. 



