244 Inheritance of Tight and Loose Paleae in Oats 



whole plant are 4-grained, and when bred on for another year the 

 character often fails to appear in any of the offspring. 



Now none of the varieties sold ever go beyond four grains to the 

 spikelet ; they are never 4-grained throughout ; and they do not 

 remain constant throwers of 4-grained forms. Moreover, it has been 

 noted at the beginning of this paper that four grains may occur 

 sporadically in varieties normally with two. (Specimen XI.) It can 

 hardly be held, therefore, that extracted pure tights with some 4-grained 

 spikelets really show a transfer of the high "nuda" number. It is 

 more likely that they are just exhibiting the effect of superabundant 

 nutrition. 



These facts incline one to conclude that when membranous paleae 

 are replaced by thick, stiff husks, the extra growth which would have 

 produced the additional grains is used up instead in the process of 

 strengthening the paleae. 



Colour. 



In this investigation the inheritance of colour has been followed 

 merely for the subsidiary purpose of discovering whether there might 

 be any connection between it and the different degrees of sclerosis of 

 the paleae. The figures from the crosses involving the white tight- 

 grained parents seemed in some respects to point to a preferential 

 linkage between white colour and tight husk ; but the results lacked 

 consistency, and adverse conditions so weathered the crop in 1916 that 

 the correct classification of light greys was rendered extremely difficult. 

 The F2 generation (raised this season) of the cross Nubian Black x. 

 Avena nuda, moreover, did not show any signs of the supposed coupling 

 being perfectly normal. In Table VI are 1225 plants raised from 60 

 coloured F^ plants showing splitting. The second cross suffered the 

 least from weathering and mice. 



I 



TABLE VI. 



Total 



Fi plants 



Pure 



tights 



Tight- 

 containers 



G W O W 



Thousand Dollar <j x Avena nuda ? 439 170 93 48 



Avena nuda 3 x Ligowo ? 259 87 55 22 



Ligowo c? X Avena nuda ? 182 88 43 26 



G 



253 

 145 

 107 



W 

 92 

 45 



47 



Hard- 

 backs 



G W 



08 18 



44 17 



21 15 



Pure 



Penulti- 

 looses 



G W G W 



27 9 8 3 



10 1 5 2 



7 — 4 — 



Grand Total 880 345 191 96 505 184 123 50 

 Expected 919 306 229| 76^ 



44 10 17 5 



