190 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXI. 



from one ear. As a rule this involves at least three years' work 

 and if there are any accidents a longer period. 



This tedious separation of the mixed wheats of a Province into 

 their ultimate constituents is an example of that drudgery in 

 scientific work which is so often necessary. As the wheats are 

 being separated and grown singly their agricultural characters, 

 rust resistance, yielding power and milling and baking characters 

 can be studied. At the same time suitable material for selection 

 and hybridization Avork becomes available. 



III. Improvement of Wheat by selection. 



In order to appreciate the modern methods of selection, which 

 can be applied to a crop like wheat, which normally self-fertilizes, 

 it is necessary to realise the constitution of an Indian wheat-field 

 and also the complexity of most of the botanical varieties of 

 wheat in India. As we have seen the botanical varieties can be 

 separated into agricultural types differing from each other in field 

 characters. It is these types which form the raw material as it were 

 for improvement by selection. The assemblage of individuals 

 constituting an agricultural type is termed a population and these 

 individuals may difier from each other in yielding power. If they 

 do the pure line which has the highest yielding power can be sepa- 

 rately propagated, and if it is a desirable wheat in all other respects 

 its selection and separate growth will constitute an improvement. 

 The essence of selection therefore depends on the comparison of the 

 offspring of single plants and not on the comparison of the plants 

 themselves. Once the best pure line in an agricultural type has been 

 selected it is believed that no further improvement is possible by 

 this method. All that is necessary is to maintain the improvement. 



Applying these principles to the wheats of India, we have been 

 able to isolate a number of wheats of exceedingly high grain 

 quality, some of which are being exhibited to-day. Some of these 

 high quality wheats also yield well, are rust resistant and are 

 being grown this jear on a large scale at a number of stations 

 in the plains. The best of these will be grown on a much larger 

 scale and will be distributed to the cultivators in those tracts 

 which suit their particular requirements. 



