1920.] 



C ROSS- Fe RTILIS A1 ION IN POTATOES . 



digging time and many valuable fertilisations are lost, but if 

 the bag is put back and fixed with its copper wire to the stem 

 with its label carefully preserved inside, then the raiser is 

 not robbed of his labours. 



When the haulm has died down, the berry with its label 

 attached and still contained within the bag should be re- 

 moved. By this time it will be found that the berry is probably 

 as much as i in. in diameter, is of a green colour shading oh' 

 into purple, and is still quite hard. It should then be kept, 

 still within the bag, in some open tray in a safe place protected 

 from mice and other possible sources of injury. In February 

 of the following year the berries should be opened and 

 the seed extracted. This is quite a simple procedure. With 

 a clean penknife the berry is split in two, the seeds squeezed 

 and scraped out and spread on a piece of clean white blotting 

 paper, 6 in. by 6 in., on which the name of both parents and the 

 date of fertilisation should be written. Each seed is surroun- 

 ded by a coat of mucilage which, on drying, will cause the seed 

 to adhere to the blotting paper. \\Tien dry the blotting 

 paper may be folded and kept in an envelope. 



Sowing: the Seed.— In the beginning of March the seed should 

 be sown. It is first necessary to separate the seed from the 

 blotting paper, w^hich is readily done with a penknife. Sowing 

 may be carried out in two ways : (a) the seed may be sown 

 broadcast in pans and covered with silver sand and 6 weeks 

 later pricked out, or, preferably {b) sown in a systematic manner 

 in seed boxes. The soil surface of the seed box should be 

 marked out in lines 2 J in. apart, drawn parallel with both its 

 sides and ends, the first line starting at i J in. from the edge of 

 the box. In this w^ay a checker-board is produced, and if a 

 single seed is placed at each intersection at a depth of i in., 

 then the ensuing plant will be 2 J in. from its nearest neigh- 

 bour. By emplo3dng this method there is no need to prick out, 

 and each seed is given a fair chance. The seed should be raised 

 under very moderate heat, and when the seedlings are about 

 I J in. high they should be cooled off and hardened. They will 

 not, however, be fit to plant out till the first week in June, 

 when each seedling will be from 6 in. to 9 in. high. 



Other Methods of Fertilisation. — It sometimes happens that 

 the operator is not able to pay the necessarv number of visits 

 to his plot in order to eftect the fertilisation in the manner 

 described, and experience has shown that results can be obtained, 

 though the method is not nearly so certain, by fertilising the 

 bud immediatelv after its anthers have been removed. In 



