A RADISH-CABBAGE HYBRID 



Cross Between Two Genera Shows Extraordinary Vigor but Absolute Sterility- 

 Pollen Irregular Both in Size and in Shape — Two Extra 

 Stamens Present in Some of the Flowers.' 



Flippo Gravatt, Blacksburg, Va. 



IT IS a general rule with organic 

 forms that whenever their system- 

 atic differences are very great, they 

 will not hybridize with each other. 

 A large number of species will hybridize 

 with other species of the same genera, 

 though the product obtained is usually 

 sterile. The great majority of species 

 will not hybridize with other species 

 of the same genus. In regard to crosses 

 between different genera a good many 

 have been reported. Each of these 

 successful crosses represents hundreds 

 of unreported failtu-es, owing to the 

 great difficulty in effecting such a 

 cross. These generic crosses have been 

 effected in various different families, 

 both in the Dicotyledons and in the 

 Monocotyledons . 



In the Cruciferae, mention was found 

 of one generic cross, that between the 

 garden radish, Raphanus sativus, and 

 the garden cabbage, Brassica oleracea. 

 This cross was made by Segeret, a 

 German, many years ago, although there 

 seems to be doubt about it in the mind 

 of Fockle, who reports Segeret's work. 



The chief distinction between the 

 genera Raphanus and Brassica are that 

 the pod of the former is one celled or 

 with spongy transverse partitions, while 

 that of Brassica is longitudinally two 

 celled and dehiscent. Between the two 

 species there are a number of differ- 

 ences, but these will be noted later. 

 The radish and the cabbage have both 

 been developed in cultivation for hun- 

 dreds of years. 



In the greenhouse during 1910 a large 

 number of flowers of three different 

 varieties of radish were emasculated 

 and bagged. Two days later, when most 

 of the stigmas were in receptive condi- 



tion, they were pollinated with pollen 

 from a cabbage plant which was a first 

 generation hybrid between the varieties 

 "Volga Russian" and "Curled Savoy." 

 Perhaps the fact that the cabbage plant 

 was a hybrid had something to do with 

 the success of this generic cross. The 

 bags were left over the pollinated 

 flowers for two weeks. At the end of 

 that time all had dropped off except 

 two small pods of the variety "Long 

 Scarlet Short Top." A large number of 

 cabbage flowers were emasculated and 

 pollinated with different varieties of 

 radish, but no fruit set. 



In September, 1910, the contents of 

 these two pods, consisting of several 

 small, shriveled seeds, were planted. 

 Only one came up and from the first 

 it could be seen that it was a cross. It 

 was very vigorous and grew rapidly, 

 finally being transplanted from a 20 

 inch pot to a central bed. 



CHARACTER OF THE HYBRID. 



The hybrid produced a great abun- 

 dance of large leaves. In size and shape 

 they are nearer to the cabbage, but are 

 much larger than those of either parent. 

 The largest leaf of the cross was five 

 feet nine inches from tip to point of 

 attachment, and one foot seven inches 

 broad. The leaf was measured at the 

 time the plant started blooming. 



In color the hybrid leaf is a mean 

 between the light green of the radish 

 and the dark or blue green of the cab- 

 bage. In taste it is more like the 

 cabbage, but one can still detect some 

 of the radish pungency. The radish 

 leaf is pubescent with stiff hairs, while 

 the cabbage leaf is glabrous. Leaves of 

 the cross are nearly glabrous. The 



^This work was carried on during post-graduate studies at Virginia Polytechnic Institute 

 under Prof. H. L. Price and Prof. E. A. Smyth. 



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