394 THE WHEAT PLANT 



The colour of the glumes was also very varied, some had white chaff, 

 others black, but few or none were as black as those of the Emmer grand- 

 parent. 



As in the previously described Black Emmer hybrid a number had 

 red or brown glumes, and pubescence was linked with the black character. 



Many plants were sterile or semi-sterile. 



3. HYBRIDS OF T. durum WITH OTHER WHEATS. 



a. T. durum x T. monococcum (see p. 391). 



b. T. durum x T. polonicum (see p. 395). 



c. T. durum x T. vulgar e. 



(i.) T. vulgar e, var. albidum (Chidham d'automne) x T. durum 

 (Ismael Velvet Chaff). The F x of this cross produced by Vilmorin 

 in 1879 had square beardless ears with a few short apical awns. 



The F 2 consisted of an extraordinary series of forms of T. durum and 

 T. vulgare, some with long awns, others beardless : both lax- and dense- 

 eared vulgar es were obtained with examples of T. compactum, T. turgidum, 

 and T. Spelta. None were like the original parents of the cross. 



(ii.) T. vulgare, var. milturum (Early Red Chief) x T. durum, var. 

 leucomelan (Marouani). The Fj of this cross made by Love and Craig 

 was a vulgare-like form, " beardless " with short, apical, black awns and 

 red grain. 



In the F 2 generation, segregation in regard to both chaff colour and 

 grain colour occurred in the proportion of 15 red : i white, the ratio of 

 the " beardless " to fully bearded being 3:1. Among the 113 descendants 

 were forms of T. durum and T. vulgare, and in addition, two typical plants 

 of wild T. dicoccoides with flat ears, brittle rachis, long hairs at the base of 

 the spikelet, and narrow, elongated grain : the proportion 113 : 2 (wild 

 forms) suggests the trihybrid ratio 64 : i. Some of the plants of this 

 generation had ears with " reversed " awns, the empty glumes bearing 

 very long beards, while the awns of the flowering glumes were quite 

 short. 



4. HYBRIDS OF T. polonicum WITH OTHER WHEATS. Artificial hybrids 

 have been obtained between T. polonicum and most of the other cultivated 

 races of wheat. Several natural hybrids have also been observed. 



With the probable exception of the cross T. monococcum x T. polonicum, 

 the hybrids are fertile or semi-fertile. 



a. T. monococcum ? x T '. polonicum d (p. 391). 



b. T. polonicum ? x T. dicoccum J. (i.) In 1916 I discovered a 

 single hybrid ear (i, Fig. 225) among the progeny of a pedigree row of 

 T. polonicum, growing in close proximity to pure lines of T. dicoccum. 

 The polonicum parent had white papery chaff, 30-33 mm. long, slightly 

 hairy on the nerves, and white flinty grain 10-11 mm. long. The 



