256 CHAPTER XIV 



less than those widely spaced ; plants on very productive soils 

 stool more than those on poor soils ; a waterlogged condition 

 of the soil inhibits the process, and the date of sowing also 

 affects tillering — e.g., winter wheat sown late does not tiller 

 as much as when sown at the correct date — a strain of wheat 

 which may have only three stems under certain conditions 

 may have under other conditions up to 80 stems. CJiven 

 optimum conditions for nutrition, then the maximum number 

 of stems will be found. 



It is because of what has been said above that, within 

 limits, widely-differing rates of seeding, except on extreme soil 

 types, on the same soil will give almost identical results as 

 regards yield. 



(6) Yield. — As in all crops each locality offers conditions 

 more suitable to certain varieties than others. Some strains 

 prove themselves more productive than other strains under 

 widely-differing conditions. 



(7) Quality of Grain. — This, of course, differs very much 

 with the breeds grown. Some highly-productive strains are of 

 poor quality — e.g.. Federation and Ked Victoria. 



Methods op Improvement. 



(1) Mass Selection. — This consists in the continuous 

 selection of a number of the best ears, grains or plants. It is 

 really the elimination of the least suitable for the locality. 



At the Ontario Agricultural College this method has 

 given the following result — viz. : — 



1890-f 



1. Oats (average for 8 years) 74 



2. Barley ,, ,, 50 



3. Potatoes ,, ,, 120 



Mass selection is most effective when the individual plant 

 is made the unit of selection, and not the individual ear or 

 grain, because large ears and large grains may be borne on 

 relatively poor plants grown in favourable environment. 



(2) Individual Selection. — " In this case the selection 

 commences with a number of superior plants of a given 

 variety, and the seed of each plant or ear is separately planted 

 and kept under observation. This enables a strict comparison 

 to be made of the progeny of each selection so that in a few 

 years the best strain in the original selections may be multi- 

 plied for future use.'"^ This is a more tedious, but a more 



