Mr Biffen, Wheat Breeding. 



281 



many ears would have been classed with the glabrous forms unless 

 they had been examined with a powerful lens. On separating the 

 velvet and smooth-chaffed plants, 223 of the former were found 

 and 116 of the latter, i.e. roughly a ratio of 2 : 1. It is conceivable 

 that the result is due to a partial shedding of the hairs as the ears 

 ripen, but I have not been able to establish this so far. 



This increased tendency for the characters to vary probably 

 explains the fact that a number of typically spelt-like ears occur 

 in the second generation of hybrids with Rivet wheat. The dis- 

 tinguishing marks of T. spelta varieties are the closed spikelets 

 and the brittle rachis. Neither of these occur in Rivet wheat or 

 the other parents, Red King, White Monarch, and Sunbrown. 

 The glumes of Rivet wheat though are keeled -and thicker than 

 those of the varieties with which it was crossed, and if this 

 characteristic should have become exaggerated the enclosed spike- 

 lets would only open with difficulty or not at all. The brittle 

 rachis would then be a necessity for " seed " dispersal. The fact 

 that some spelt-like ears, which will shed their grain on rubbing 

 between the hands and having a tough rachis, are found, tends to 

 give support to this view. 



All of the well-known races of spelts are represented among the 

 hybrids — bearded, beardless, grey, red and white. Should any of 

 these breed true the presumption will be that T. spelta has arisen 

 from T. vulgare and T. turgidum. 



One point of special interest in Spillman's paper is that 

 a cross between a lax-eared and dense-eared wheat gave rise to 

 hybrid plants, with ears intermediate in length between the 

 parents, and the succeeding generation consisted of long, inter- 

 mediate, and short types, in the proportion of two intermediates 

 to one long and one short. I have not met with similar results 

 among my lax and dense crosses at present. One typical inter- 

 mediate hybrid has been raised though by crossing Polish wheat 

 (T. Polonicum) with Rivet wheat. The former is characterised by 

 the enormous size of its glumes and grain when compared with 

 our commonly cultivated varieties. In the hybrid the glumes and 

 grain are intermediate between the parent forms, e.g. : — 



In other words, although the influence of Polish wheat shows 

 clearly in the hybrids there is no dominance of long glumes and 



