Depabtment of Experimental Plant-Breeding. 31 



(2) Statistical studies of similar plants grown under various arti- 

 ficial environments to determine, if possible, whether variation in any 

 given direction can be increased. 



(3) Experiments to determine the value of mutations in plant- 

 breeding. 



(4) Experiments to determine the cause and meaning of muta- 

 tions as distinct from other types of variation. 



(5) A study of the mutations of wild plants and their importance 

 in the formation of new types or species in nature. 



(6) Experiments to determine whether it is possible by chemical 

 injections or other artificial stimulation applied at certain definite 

 times or continuously, to cause plants to produce mutations or varia- 

 tions of any type of use to the breeder in securing new strains. 



Considerable advance has been made on several of these problems 

 and it is expected that several papers will be ready for publication 

 within the next year. 



Investigational on the laws of inheritance in hybridization.- 



The purpose of these investigations, which are of primary import- 

 ance in extending our knowledge of the fundamental principles of 

 breeding, is to get further data with reference, (i) to the general ap- 

 plication of Mendel's Law of hybrids in different groups of plants ; (2) 

 to the relative influence of male and female in the offspring; (3) to the 

 transmission of characters to be expected in hybridization, when 

 nearly related and distantly related parents are used ; (4) to the limits 

 of possible hybridization; (5) to the origin of character correlations 

 of the coherital type and their transmission in hybridization, etc. 



Investigations of this nature require considerable time as three 

 or four generations of hybrids of known parentage must be grown 

 before safe conclusions can be drawn. Again, in starting the work 

 strains of known origin must be secured of the forms used in the ex- 

 periments, and this in some cases may require several years of culti- 

 vation under controlled conditions. Considerable work of this nature 

 has been started with tomatoes, phlox, verbenas, peppers, poppies and 

 other plants. In work of this nature, plants must be selected which 

 are the best adapted for the particular purpose^ under consideration, 

 whether or not they are of any practical value. The work of this 

 nature at first requires but little attention, the amount of work greatly 

 increasing as the investigations progress. It is expected that some of 

 the practical experiments outlined above will be completed before 

 the work on these more scientific subjects reach a stage where they 

 will demand any great amount of attention. 



