43 



the summer to determine the causes and conditions of this 

 development of shoots, and a careful study of their life history 

 is being made. 



In the spring, over lOO scions from the resistant New York 

 trees were secured and sent to the U. S. Dept. of Agriculture for 

 grafting upon Chinese and Japanese chestnut and on various 

 hybrids. This work is being carried on in collaboration with 

 the Laboratory of Forest Pathology, Bureau of Plant Industry, 

 U. S. D. A. 



Genetics and Plant Breeding 



Investigations on the Laws of Heredity and Variation in Plants. 

 By Orland E. White and L^orothy I. Neff 



The genetic analysis of peas (P^'5mot).— -Investigations on 

 inheritance and variation in several hundred varieties of field 

 and garden peas have been carried on in 1924, as in previous 

 years. These varieties, collected from many different countries, 

 include both wild and domestic types, varieties, and species. 

 Many have very peculiar and little known characters. 



Accounts of the genetic investigations of these characters 

 have been published and referred to in previous years. A 

 resume of all work on the genetics of peas has also been published. 

 Work during the year largely centered on such characters as 

 height, pod-color, pod-shape, foliage color, and certain seed- 

 coat colors and patterns. Data have been accumulated sufficient 

 for several papers during 1925. Insufficient greenhouse facilities, 

 coupled with lack of sufficient trained assistance have greatly 

 impeded the prosecution of this work. 



Genetic investigation of hollyhocks . — Studies on heredity and 

 variation in the numerous varieties of the garden hollyhock were 

 begun during 1924. Several hundred flowers w^ere either crossed 

 or selfed. The various types used numbered about thirty, 

 including double, semi-double, and single flower forms. All 

 types were found to be perfectly self-fertile, and in most cases 

 to give plenty of seed when protected from foreign pollen by 

 glassine bags. Good seed was obtained from doubles when selfed. 

 All types so far experimented with readily cross, and their flowers 

 bear considerable mutilation, attendant to removing the anthers, 

 without blasting. 



