30 JAMESTOWN CONGRESS OF HORTICULTURE 



of successful crosses between the hairy leaved turnips and the ruta- 

 baga, but none appears to have risen to commercial importance. 



Celery. Appears wholly a product of evolution by selection. The 

 present tendencies on one hand are to breed for early maturity and 

 quick bleaching and on the other to seek in the deep-green leaved 

 varieties good keeping quality and resistance to bacterial disease. 



Cucumbers and Melons. Intentional as well as natural crossing 

 plays an important part in the development of these popular vine fruits. 

 Most strains of forcing or glasshouse cucumbers are the results of 

 crossing our white spine variety with the long smooth cucumbers so 

 extensively grown abroad. In these dilute variety-hybrids the white 

 spine type of fruit prevails, but the vigor of plant of the European 

 kinds is retained. Glasshouse melons appear to an even greater extent 

 to be the direct results of crossing. In most instances records of par- 

 entage are preserved, as being of commercial importance. Among 

 outdoor varieties hand-made crosses are less in evidence, the seed 

 grower practicing careful selection and isolation of varieties to main- 

 tain purity of type, but crossing is so readily affected by natural agencies 

 that most distinct varieties probably originated in that manner, to be 

 later perpetuated by selection. 



Table Corns. Are cross-bred with comparative ease and certainty. 

 Three years of selection will usually fix a desirable cross sufficiently for 

 dissemination. Many successful crosses have been made for purely 

 local uses. By far the greatest interest in corn breeding lies in the 

 vast efforts being made by experiment stations, societies and indi- 

 viduals to increase productiveness and develop special characteristics in 

 field corn varieties. 



Lettuce. Has hitherto been developed by selection and wonderful 

 variations have been produced. The U. S. Department of Agriculture, 

 however, announces that a successful cross has been made between the 

 loose-leaved Grand Rapids type and a large heading variety, like Big 

 Boston, probably the first intentional cross-breeding achieved in this 

 important salad vegetable. 



The Onion. Is one of the most ancient and widely dispersed of 

 aromatic vegetables. Various species of Allium are cultivated in differ- 

 ent parts of the world and it would appear that fair opportunities for 

 methodical hybridization exist. Attempts to intercross varieties of A. 

 cepa, the garden onion, with A. Porrum, the leek, and A. fistulosum, 

 the Welsh onion, in the hands of the writer completely failed. The 

 crossing of Prizetaker, a large Mediterranean variety of garden onion, 

 with Red Wethersfield resulted in attractive intermediate offspring 

 that reproduced quite true from seed. 



Peas and Beans. Are constantly subject to the most careful se- 

 lection, yet a considerable number of the most prized varieties, espe- 

 cially among peas, are products of intentional crossing. Beans are 

 rather difficult subjects to artificially pollinate, yet successful hybrids 

 between the Lima and garden pole bean, belonging to fairly diverse 

 species, have been made by more than one breeder. Investigations 

 show that these garden legumes, while popularly supposed to be self- 



