INHERITANCE -IMPROVEMENT BY BREEDING 147 



Table XXX. 



YIELD PER ACRE FROM A 75 PER CENT STAND, AT VARIOUS 

 AVERAGE WEIGHTS PER EAR. 



CHAP. 



V. 



Thus every single ounce of grain added to tke average weight of ear pro- 

 duced makes a difference of 2 muids of grain per acre. 



plants are in the majority, as is generally the case in ordinary 

 maize crops from unselected seed, they cross with the good 

 ones and cause deterioration. The obvious remedy is (i) to 

 save only the best ears for seed, and (2) to plant this seed 

 entirely away from the rest of the crop so that the plants 

 may not be cross-pollinated by inferior strains. 



It is true that large heavy-yielding ears do not always 

 produce good ears in the next generation, but this is often due 

 to the effect of previous cross-breeding with inferior plants, 

 which continues to show in the second and even the third 

 generation. 



It seems reasonable to expect that by using only the ten 

 best ears of the crop for seed, we shall be able to breed up a 

 strain that will eventually average a yield of 11 '57 ozs. of 

 grain per ear, which on a 75 per cent stand will give 23 muids 

 per acre. There may be some adverse factors to contend with, 

 which are not yet fully understood, and which may delay the 

 attainment of this desired end ; but South Africa can un- 

 doubtedly do much better than at present. 



In tests made during 1908 the average difference in weight 

 of grain per ear from the ten best ears, as compared with that 

 obtained from the ten poorest ears, was 2 '68 ozs., while the 

 range of difference was from 97 oz. to 4-33 ozs. Though 



10* 



