TV. THE PRESENCE AND ABSENCE OF AWNS. 



The inheritance of awns in wheat has been investigated bv 

 several observers and the results obtained are to be found in 

 von Tschermak's summary in Die Zilchtung, which has been referred 

 to under chaff colour. Biffen. Wilson. Schribaux and von Tschermak 

 found that the beardless condition was dominant and that the F,> 

 generation was composed of bearded and beardless plants in the 

 simple ratio 3: J. In some cases the ratio fully bearded to half 

 bearded and beardless in this generation was 1 : 2:1. Nilsson- 

 Ehle found however that the beardless condition was not absolutely 

 dominant. Von Tschermak observed in two cases in crossing a 

 bearded and beardless wheat that the bearded condition was entirely 

 lost, while Rimpau and Spielmann on crossing two beardless wheats 

 obtained in the F, a few bearded forms which bred true. 

 Saunders 1 in 1906 combated the statement that the first generation 

 between a beardless and a bearded wheat is always beardless, and 

 maintained that the amount of bearding in the F, varies with 

 the wheats used. In the F 2 a series of forms, which defied class- 

 ification, was obtained. Apparently the subject was not further 

 investigated as no details appear to have been published 

 since. 



In our investigations at Pusa with Indian wheats the inherit- 

 ance of the fully awned character has not been simple. In 

 crosses between bearded and beardless wheats two very distinct 

 phenomena have been observed. Tn one series, the plants in the 

 F 1 were distinctly intermediate and were half bearded, while in 

 the other only very short tips to the glumes occurred. These 

 differences in the F! were correlated with differences in the 

 beardless parents. In the first case these had short tips to the 



I Saunder?, Report of the Third International Conference 1906 on Genetics. London, 1907, 

 p. 370. 



