Hybridization 



117 



was therefore unlike either parent, an accurate comparison 

 could not be made. But they compared well with com- 

 mercial egg-plants, and un- 

 doubtedly they would have 

 shown themselves to be 

 more productive than com- 

 mon stock could they have 

 grown a month or six weeks 

 longer. Professor Munson, 

 of the Maine Experiment 

 Station, grew some of this 

 crossed stock in 1891, and 

 found that it was better 

 than any commercial stock 

 in his gardens. 



In extended experiments 

 in the crossing of pumpkins, 

 squashes, and gourds, con- 

 ducted several years, in- 

 crease in productiveness 

 due to crossing has been 

 marked in many instances. 

 Marked increase in produc- 

 tiveness has been obtained 

 from tomato crosses even 

 when no other results of 

 crossing could be seen. 



Three factors . Attention 

 has been called by Willis to 



three factors in the gain resulting from cross-fertilization, 

 viz. (a) fertility of mother plant ; (6) vigor of offspring ; 



FIG. 32. Hybrid walnut and 

 parents : ra, California black 

 walnut (Juglans calif ornica), 

 male parent; /, Eastern black 

 walnut (J. nigra), female par- 

 ent; h, hybrid. Natural size. 

 (After Burbank.) 



