GREGOR MENDEL 



of the seeds was spared. In the last few years it has been necessary to dis- 

 continue cultivation of peas in the vicinity of Briinn. The seeds remaining can 

 still be useful, among them are some varieties which I expect to remain 

 constant; they are derived from hybrids in which two, three, and four differ- 

 entiating characters are combined. All the seeds were obtained from members 

 of the first generation, i.e., of such plants as were grown directly from the 

 seeds of the original hybrids. 



I should have scruples against complying with your honor's request to send 

 these seeds for experimentation, were it not in such complete agreement with 

 my own wishes. I fear that there has been partial loss of viability. Further- 

 more the seeds were obtained at a time when Bruchus pisi was already ram- 

 pant, and I cannot acquit this beetle of possibly transferring pollen; also, 

 I must mention again that the plants were destined for a study of differences in 

 flowering time. The other differences were also taken into account at the 

 harvest, but with less care than in the major experiment. The legend which I 

 have added to the packet numbers on a separate sheet is a copy of the notes I 

 made for each individual plant, with pencil, on its envelope at the time of 

 harvest. The dominant characters are designated as A, B, C, D, E, F, G and as 

 concerns their dual meaning please refer to p. 11. The recessive characters are 

 designated a, b, c, d, e, f, g; these should remain constant in the next genera- 

 tion. Therefore, from those seeds which stem from plants with recessive char- 

 acters only, identical plants are expected (as regards the characters studied). 



Please compare the numbers of the seed packets with those in my record, to 

 detect any possible error in the designations — each packet contains the seeds 

 of a single plant only. 



Some of the varieties represented are suitable for experiments on the germ 

 cells; their results can be obtained during the current summer. The round 

 yellow seeds of packets 715, 730, 736, 741, 742, 745, 756, 757, and on the other 

 hand, the green angular seeds of packets 712, 719, 734, 737, 749, and 750 can 

 be recommended for this purpose. By repeated experiments it was proved that, 

 if plants with green seeds are fertilized by those with yellow seeds, the albumen 

 of the resulting seeds has lost the green color and has taken up the yellow color. 

 The same is true for the shape of the seed. Plants with angular seeds, if 

 fertilized by those with round or rounded seeds, produce round or rounded 

 seeds. Thus, due to the changes induced in the color and shape of the seeds by 

 fertilization with foreign pollen, it is possible to recognize the constitution of 

 the fertilizing pollen. 



Let B designate yellow color; b, green color of the albumen. 



Let A designate round shape; o, angular shape of the seeds. 



If flowers of such plants as produce green and angular seeds by self-fertiliza- 

 tion are fertilized with foreign pollen, and if the seeds remain green and 

 angular, then the pollen of the donor plant was, as regards the two characters 



ab 



If the shape of the seeds is changed, the pollen was taken from Ab 



If the color of the seeds is changed, the pollen was taken from aB 



If both shape and color is changed, the pollen was taken from AB 



