PKINCIPLES OF FEUIT-GROWIN'G AND DEVELOPMENT. 105 



In from six to ten days the sacks can be taken off, as tlie 

 ovaries will then indicate success or failure. Those with 

 enlarged ovaries are covered with mosquito bar, which may 

 remain until the fruit is perfectly developed as a protection 

 from birds and insects and to distinguish the pollinated 

 fruits. 



110. Speedy Testing of the Crosses and Hybrids. — The 

 small lots of seeds developed by crossing are usually kept 

 in flower-pots mixed with sand (5). "When the seedlings 

 produced are one year old the tops can be cut off just 

 above the crown late in autumn and used the next spring 

 for top-working on young bearing-trees of the same 

 species (88). By ringing (40) the branch after it has made 

 two years' growth we can usually secure fruit for testing 

 the third year. The seedling crosses cut back will start 

 from the stub the next spring and can be used to deter- 

 mine the relative thrift and hardiness of the new variety 

 on its own roots. 



