64 



The Journal of Heredity 



one would expect that in F3 certain 

 families would be found which would 

 produce more of the wild types. Only 

 one such family was obtained, however. 

 Owing to the fact that there was a 

 poor stand in F^ due to a heavy rain 

 just after sowing, it cannot be said 

 definitely that more families did not 

 exist which may have produced wild 

 forms if a full stand had been obtained. 

 It seems, however, that enough plants 

 were obtained so that, if as many fami- 

 lies produced, or would have produced, 

 wild plants as expected in F3, a number 

 of wild plants would have been ob- 

 tained in this generation. More evi- 

 dence on this point cannot be obtained 

 until this cross is repeated, which is 

 now being done. 



The occurrence of these forms may 

 lead to the conclusion that the wild 

 wheat of Palestine is the prototype of 

 our domestic wheats and that the fac- 

 tor or factors necessary to its produc- 

 tion were carried by either of the 

 parent forms and that through some 

 fortunate combination of factors the 

 wild types were produced. If this were 

 true, then is it not possible that many 

 varieties may carry these factors and 

 that through crossing these the wild 

 wheat forms would be produced ? Such 

 does not occur, however, for in several 

 hundred different wheat crosses under 

 our observation no such wild types 

 have been produced except those in the 

 one cross discussed. These combina- 

 tions include crosses between the em- 

 mers, spelts, durums, clubs, and com- 

 mon wheat. 



It is possible that these forms 

 may have occurred through mutative 

 changes so far as the factors for the 

 production of type of rachis, basal 

 hairs, shape of kernel and the like. It 

 has been noted that there were segre- 

 gations in F4 and F5 regarding awns, 

 so that if a mutation did occur it was 

 not one affecting all the characters but 

 only those mentioned. If it is later 

 evident that these types have arisen 

 through mutation, it will be interesting, 

 since it will be the origin of a type 

 with dominant characters. Such cases 

 are rather rare. 



Since these wild-like forms have 

 occurred through crossing it does not 

 follow that the wild wheat of Palestine 

 is certainly a prototvpe of the common 

 wheat. For, as suggested above, we 

 might expect such occurrences more 

 commonly. For example, in Avena 

 crosses the wild A. fatua is not pro- 

 duced commonly, if ever, when crosses 

 between different types of oats are" 

 made,*^ even though the varieties of 

 A. sativa are thought to have been 

 deived from A. fatua. 



From the evidence one might well 

 put forth the suggestion that the wild 

 wheat of Palestine may have been pro- 

 duced originally through a natural 

 cross. Owing to its very excellent 

 adaptations for self-dissemination it 

 would naturally spread and fill up waste 

 places. The wild oat of the west is 

 more common in waste places than in 

 cultivated fields. It occurs in cultivated 

 fields but, o^ying to cultivation, is not 

 so common. Wild wheat, then, may 

 even exist occasionally, though un- 

 noticed, in cultivated fields. 



The occurrence of wild segregates in 

 the cross described does not prove that 

 the wild wheat is the prototype of 

 wheat, but rather raises the question 

 whether it really is a protoype or a 

 contemporary form. More data from 

 other crosses will be needed before any 

 definite statement can be made. May 

 it not be possible that there is a certain 

 type (or types) in Palestine that, when 

 crossed with others, may frequently 

 produce the wild type? 



CONCLUSION 



A wild type of wheat was prodviced 

 by crossing a durum with a common 

 wheat. 



This type of segregates from this 

 type was similar in all respects to the 

 typical wild wheat of Palestine. 



The occurrence of this wild form 

 may be evidence in favor of the proto- 

 type theory in relation to the wild 

 wheat of Palestine or indicate that 

 such a wild form may have arisen 

 through natural crossing between al- 

 ready existing forms. 



" The authors have some evidence that such may be produced in certain crosrc';. 



