448 Journal of Agricultural Research voi. xxii. no. s 



On account of the low ash content of the rachis of the Coast barley 

 (fig. 5), varieties of this type may be useful in the production of non- 

 shattering awnless and hooded sorts. Barleys of the Coast group prob- 

 ably take less ash from the soil than do most others. There certainly is 

 less deposited in the awns and rachises than in those of the other common 

 varieties. Crosses of hooded varieties with varieties of the Coast type 

 should give hooded segregates which are less brittle than the common 

 hooded forms. Indeed the Meloy, one of the best hooded varieties under 

 cultivation, is probably the result of such a cross. In a more complex 

 cross it might be possible to use some of the characters of the Hanna 

 variety. The Hanna is not classified as a shattering variety, yet its 

 rachis contains a high percentage of ash. In this case the rachis is able 

 to withstand a heavy deposit. It is possible that this resistance might 

 also be of use, although hooded crosses of this sort, when not combined 

 with the Coast, have not been very promising. In this connection it is 

 desired not to overemphasize the relation of ash content to shattering. 

 There is an obvious relation, but the ash content is only one of a number 

 of factors. The tenacity of the vascular bundles, the character of the 

 cell walls, and the size of the rachis, all have a bearing on shattering. 

 There is also more than one type of shattering. In the Manchuria 

 barley, for instance, when grown in Idaho under irrigation, the kernels 

 become loosened from the spike without the rachis itself being affected. 

 In this case the ash content of the paleas may have some bearing on 

 deciduousness. 



The ash of the kernel is of particular interest. In this case all of the 

 ash is contained within cells which are engaged in highly active meta- 

 bolism. The ash is either in the cell sap itself, the active proteid content, 

 or the cell walls. When the ash is computed on total wet weight a very 

 uniform percentage is maintained. It is obvious that at no time is any 

 part of the kernel set aside as a repository for ash. There is very little 

 difference between the kernels of plants which are dying from drouth and 

 those which are growing under an ample supply of water. Why the ash 

 content of the active kernel is maintained at a nearly constant precentage 

 and whether a higher percentage of ash than that exhibited interferes 

 with normal metabolism is not indicated from these analyses. That the 

 uniform percentage of ash in some way is connected with the fundamental 

 processes of growth is indicated further by the fact that the percentage 

 coincides with that found in roots, tubers and fruits, all storage organs, 

 and even with that of meat and eggs. 



The percentage of ash based on the wet weight of kernel is not quite 

 constant. There is a loss in percentage immediately following fertiliza- 

 tion and then a gradual increase until full maturity. This behavior can 

 not be adequately interpreted. It appears that at the time of fertiliza- 

 tion the ash content of the ovary is very high. Immediately after fer- 

 tilization there is a decided distention, partially due to the turgidity of 



