HYBRIDISATION AND WHEAT HYBRIDS 391 



spikelet, and the presence of two awns on each spikelet : crossing of the 

 F! with the parent forms does not succeed. 



a. (i.) T. monococcum, var. flavescens 9 (Engrain double) x T. dicoccum, 

 var. farrum $ (Amidonnier blanc). This hybrid was obtained by Bei- 

 jerinck in 1882 and its reciprocal a little later. Both were similar to each 

 other and quite sterile ; the gynaecium was apparently perfect, but the 

 anthers did not open or shed pollen. The leaves of the hybrid were 

 yellowish-green, and the nodes of the stem hairy like those of T. mono- 

 coccum. 



In general appearance the ears were intermediate between the two 

 parents ; the empty glume had a curved apical tooth, somewhat similar 

 to that of the male parent, the characteristic lateral tooth of T. monococcum 

 being very much reduced or absent. 



(ii.) T. dicoccum, var.pycnurum $ x T. monococcum, var.flavescens <$ . 

 This hybrid was obtained by Vavilov, from whom I received specimens 

 of the parents and the l plant in 1914. The hybrid was sterile with 

 ears intermediate in size between those of the two parents. In the 

 glabrous polished surface and reddish colour of the glumes, as well as 

 in the velvety surface of the leaves, it resembled the mother plant. 



b. T. monococcum x T. durum. Blaringhem obtained the hybrid T. 

 monococcum, var. vulgar e x T. durum (an Algerian form). Three hybrid 

 grains were produced by the same ear. 



The Fj plants grew vigorously, their ears resembling those of T. 

 dicoccum. One of the plants was completely sterile, the other two were 

 semi-fertile. 



The F 2 and F 3 generations of the latter consisted of plants with the 

 vegetative characters and late-ripening habit of T. monococcum. Most of 

 the ears were sterile and resembled those of T. dicoccum : the fertile ears 

 had fewer spikelets and were more like those of T. durum. 



Tschermak also obtained a hybrid between T. monococcum and T. 

 durum. 



c. T. monococcum x T. polonicum. 



T. monococcum, var. flavescens $ x T. polonicum, var. compactum, 

 Link <$ . 



Blaringhem succeeded with this cross in 1913. From one cross- 

 pollinated ear of T. monococcum seven shrivelled grains incapable of 

 germination were obtained, while from another ear of a different plant of 

 the same pure line growing near and pollinated at the same time seven 

 viable well-developed grains were produced. In both cases the pollen 

 parents belonged to the same pure line, but were different individuals. 



Tschermak also obtained a hybrid between T. monococcum and T. 

 polonicum. 



d. T. monococcum x T. turgidum. The hybrid T. turgidum $ x T. 



