Department of Plant-Breedixg. 51 



Studies on the lazvs of inheritance. — In connection with the plant- 

 breeding work, studies of the laws of inheritance, which are as yet im- 

 perfectly understood, are of great importance. Considerable work of 

 this nature has been started and includes the study of Mendelian segre- 

 gation and recombination in connection with such characters as form, 

 size, flavor, color, etc. Experiments are being conducted by Dr. A. W. 

 Gilbert on tomatoes, phloxes, salpiglossis, and morning glories, with 

 special reference to the laws of inheritance governing the transmission 

 of color and shape. In connection with these experiments, about 6,000 

 tomato plants and several thousand phlox plants have been grown during 

 the past summer. Another experiment which consists of a study of the 

 Mendelian segregation in such characters as color and shape of fruit in 

 peppers has been conducted for three seasons and some very valuable 

 scientific data have been obtained. 



Some Mendelian work has also been done on radishes for the last 

 two seasons. Color and shape of root, color of flower, and length of 

 seed pod are the factors being w-orked with. The first-generation plants 

 were grown in the garden the past summer and the second-generation 

 are now being grown in the greenhouse. 



Work of similar nature is also being conducted with schizanthus, car- 

 nations, and nasturtiums. 



Studies of mutations and their use in breeding. — The study of muta- 

 tions occurring within the different crops and wild plants is of impor- 

 tance in order to determine what bearing they may have on practical 

 breeding. The study of the striking variations found in timothy which 

 are probably to be interpreted as mutations has been continued. While 

 closely connected with the practical breeding experiments with timothy 

 as above discussed, this study is, nevertheless, of great interest from the 

 scientific standpoint in the study of mutations, and is therefore being 

 pursued more carefully than would be required were we dealing only 

 with the production of new varieties of value. 



Studies in the cumulative action of selection. — The studies on the 

 cumulative action of selection which were outlined in the last report of 

 this department have been continued in much the same manner. This 

 breeding is being done mainly with pure lines. The main crops worked 

 with are wheat and oats. However, some work is being done with cow- 

 peas and garden peas. 



Studies on correlation in breeding zvork. — One very important line of 

 work in both plant and animal breeding is the study of correlations and 

 the value they may have in practical work. The study of correlations 

 occurring in corn, which was fully outlined in our last report, is in press 

 and will soon be ready for distribution. 



