78 



BREEDING CROP PLANTS 



crosses between any form in the first group, with any form in the 

 second group gave all cultivated forms of the spelt and emmer 

 groups in later generations. Tschermak (1913) obtained similar 

 results only from crossing solid and hollow stemmed varieties of 

 the respective groups and only obtained polonicum forms when 

 using polonicum as one of the parents. 



FIG. 17. Wild wheat from Palestine and the New Hybrid. Here is shown a 

 spikelet of the true wild wheat and one of the hybrid forms. (After Love and 

 Craig, 1919.) 



T. dicoccoides was reported as being found wild as early as 

 1885. Aaronsohn (1910) found many wild forms of T. dicoccoides 

 in Palestine. Love and Craig (19196) have produced T. dicoc- 

 coides synthetically by crossing durum and common varieties, 

 which indicates rather close genetic relationships between these 

 forms. There seems no very good reason to the writers for 



