EXPEKIMENTS IN PLANT HYBRIDISATION. 



13 



by crossing. As regards the form of the hybrids in these cases, the trials 

 showed throughout that this invariably more nearly approaches to that 

 one of the two parental plants which possesses the greater number of 

 dominant characters. If, for instance, the seed plant has a short stem, 

 terminal white flowers, and simply inflated pods ; the pollen plant, on the 

 other hand, a long stem, violet-red flowers distributed along the stem, and 

 constricted pods, the hybrid resembles the seed parent only in the form of 

 the pod ; in the other characters it agrees with the pollen parent. Should 

 one of the tw^o parental types possess only dominant characters, then the 

 hybrid is scarcely or not at all distinguishable from it. 



Two trials were made with a larger number of plants. In the first trial 

 the parental plants differed in the form of the seed and in the colour of 

 the albumen ; in the second in the form of the seed, in the colour of the 

 albumen, and in the colour of the seed-coats. Trials with seed characters 

 give the result in the simplest and most certain way. 



In order to facilitate study of the data in these trials, the different 

 characters of the seed plant will be indicated by A, B, C, those of the 

 pollen plant by a, b, c, and the hybrid forms of these characters by Aa, 

 Bb, and Cc. 



Trial 1. — AB, seed parents ; ab, pollen parents ; 



A, form round ; a, form angular ; 



B, albumen yellow. b, albumen green. 



The fertilised seeds appeared round and yellow like. those of the seed 

 parents. The plants raised therefrom yielded seeds of four sorts, which 

 frequently presented themselves in one pod. In all 556 seeds were yielded 

 by 15 plants, and of these there were : — 



315 round and yellow, 

 101 angular and yellow, 

 108 round and green, 

 32 angular and green. 



All were sown the following year. Eleven of the round yellow seeds did 

 not yield plants, and three plants did not form seeds. Among the rest : 



38 had round yellow seeds ...... AB 



65 round yellow and green seeds ..... ABb 



60 round yellow and angular yellow seeds . . . AaB 

 138 round yellow and green, angular yellow and green seeds AaBb. 



From the angular yellow seeds 96 resulting plants bore seed, of which : 



28 had only angular yellow seeds aB 

 68 angular yellow and green seeds aBb. 



From 108 round green seeds 102 resulting plants fruited, of which : 



35 had only round green seeds Ab 

 67 round and angular green seeds Aab. 



The angular green seeds yielded 30 plants which bore seeds all of like 

 character ; they remained constant ab. 



The offspring of the hybrids appeared therefore under nine different 



