122 Gardening 



" 



A"eu> Jersey Ex pi. stn. 



FIG. 73. Three new varieties oi squashes produced by crossing a white scallop 

 summer squash (P, at the left side of picture) with a warty, yellow-colored sum- 

 mer crookneck (P, at right side). The photograph shows three new varieties 

 that have been produced. The upper row shows a type of short-necked "jug" 

 fruit of medium size with a smooth, cream-colored surface. The middle row 

 shows a longer-necked type of "jug" fruit, somewhat like the crookneck in shape, 

 but green-striped and not warty. In the lower row the fruits are very thin- 

 fleshed, nearly spherical, cream-colored, and not warty. After the first crossing, 

 the plants were selected and self-bred for five generations, after which some of 

 the new kinds would breed true enough to make new varieties. 



shape, size, color, and quality of flesh. Selection and 

 breeding of these hybrids will develop new varieties 

 (Fig. 73). 



New varieties are usually first described in the seed 

 catalogues as " novelties." In the course of time 

 novelties may become standard varieties, or they may be 

 discarded because they prove unworthy of cultivation. 



How the plant breeder works. In cross-breeding 

 plants, the breeder needs to know for a certainty what 

 the parents are. He, therefore, first selects the two 

 plants that he wishes to cross. Then he applies the 

 pollen from one of them to the pistil of one or more 

 flowers on the other. To prevent self-pollination or 

 stray cross-pollination he may remove the stamens from 

 the flower that is to be pollinated, cover it with a paper 

 bag, or carry out such other measures as* may be neces- 



