DISCOVERY 



347 



few and weak shoots under ordinary conditions. 

 Should they, however, be placed in a warm greenhouse 

 for a few days, apparently- the enzyme is developed and 

 growth will proceed more or less normally when " seed " 

 is planted. 



The potato crop has been greatly increased in recent 

 years by selection of varieties and also by producing 

 new varieties by crossing. The hybridist takes two 

 varieties which have the characteristics which he 

 requires, and after duly preparing the flower of the one 

 by removing the pollen bearers, or anthers, he places 

 the pollen from the other plant on the female portion 

 of the plant which is to bear the seed. If successful— 

 and it is but a small percentage which are — true seed is 

 formed in the potato apple or fruit. After suitable 

 treatment, this seed is sown, usually in a greenhouse, 

 the following spring, and when the new plants are large 

 enough, and weather is suitable, they are planted out. 



Only few and small tubers are formed the first year, 

 and the tubers are used as " seed " the following two 

 or three years until a stock of the new variety is 

 obtained, and its characteristics are manifested. 

 Should it prove different and superior to varieties 

 already in commerce, the raiser takes steps, either 

 himself or by selling it to a firm who will do it, to in- 

 crease the stock, and every effort is made to get as many 

 plants as possible from the few " seed " tubers avail- 

 able. This is done by using up the e\'es to produce 

 plants, and also by taking cuttings and striking them 

 under glass, so that a large number of plants are avail- 

 able for growing out-of-doors to produce a further 

 stock of tubers. 



Many of the varieties now in commerce have been 

 produced tlus way, with the exception that, while the 

 female plant is known, the male plant can only be 

 guessed at, owing to the fact that many of the 

 raisers used mixed pollen which had been obtained 

 from various varieties, and no one knows which variety 

 produced the pollen grain which successfully fertilised 

 the ovule (egg cell) of the female. 



Another curious note in connection with the pro- 

 duction of new potatoes is that a seed ball will produce 

 seed which will give rise to plants which are quite 

 distinct from each other, and different varieties ha\-e 

 been raised from the same potato apple. Nowadays, 

 when the pKJtato raiser has a new variety, he usually 

 sends it to the potato-testing station at Ormskirk in 

 order to find out if it is immune to wart disease (see 

 June number of this Journal, p. 179). Before a 

 potato is placed on the market, the raiser has to see 

 that it has characteristics which commend itself to 

 purchasers, as the public has very decided tastes in the 

 matter of a potato. Thus the public will not have a 

 coloured potato, and farmers who have grown such will 

 not be able to sell their produce except at well under 



{Continued on p. 343 



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