ANNUAL REPORT, 1944-45 55 



Lethal Incompatibilities Between Clonal Stocks and Varieties of Apples. (J. K. 



Shaw and L. Southwick.) The varieties and strains growing on the clonal stocks 

 Spy 227 are now in their third year from the bud. Only three varieties of com- 

 mon apples are growing normally. They are Shotwell Delicious, Paragon (Iowa 

 strain), and strain G of Mcintosh. Yates, ''Paragon L", and Mcintosh strain 12 

 are alive but making little or no new growth. Golden Delicious trees are nearly 

 all dead, but a few have weak shoots from the base of the tree. Those now com- 

 pletely dead are Delicious, Starking, Richared, Stayman, Stamared, Blaxtay- 

 man, Winesap, Arkansas Black, Arkansas, Mammoth Black Twig (Iowa Strain) 

 Turle)', Blackmack, and Mcintosh strains 1, 8, 39, 45, and R. The ornamental 

 crabs, Malus atrosanguinea, floribunda, hupehensis, sargenti, toringoides, and 

 Bechtel crab are all growing normally. Mcintosh R, Stayman, and Winesap, 

 which failed when budded on Spy 227, are still growing vigorously on the two 

 clonally propagated rootstocks Spy 227-2 and Spy 227-12 which came from seed- 

 lings of Spy 227. Further studies planned to throw light on the nature of this 

 lethal incompatibility are being carried on. A second paper reporting on this 

 project appears in Volume 45 of the Proceedings of the American Society for 

 Horticultural Science. 



Study of the Bud Sports of the Mcintosh Apple. (J. K. Shaw and L. Southwick.) 

 None of the strains reputed to be distinctly striped have yet fruited. Several 

 strains reputed to be uniformly red have fruited, also one random selection con- 

 sidered to be an ordinary Mcintosh. This seems to be slightly inferior in color 

 to the strains selected for high color. Those fruiting are growing on very dwarfing 

 stocks while none of the striped strains are on very dwarfing stocks. Spring 

 frosts in 1944 and 1945 have interfered with cropping in this orchard. Further 

 observations are needed before any positive evaluation of these red strains can 

 be made. Doubtless the distinctly striped strains should be avoided. 



The orchard of seven strains on three clonal stocks, now in its fourth year of 

 growth, shows no significant differences in vigor of these strains. The present 

 differences in size of the trees seem to be due to environmental conditions and the 

 size of the trees when set. 



The Genetic Composition of Peaches. (J. S. Bailey and A- P. French.) Since 

 there was a crop in 1944, further data were collected on two lots of seedling peaches 

 and three were selected as worthy of further trial. 



In the spring of 1945, some seedlings from the northern Caucasus region, re- 

 ported to be very hardy in bud, were set in an orchard to compare their hardiness 

 with that of Elberta and Greensboro. 



Tree Characters of Fruit Varieties. (J. K. Shaw, A. P. French, O. C. Roberts, 

 and L. Southwick.) This project has been under way for many years and the 

 basis for identifying practically all varieties of apple, pear, plum, and cherry, 

 originating as seedlings, has been established. The apple variety Van Buren, 

 believed to be a bud sport of Oldenburg, is the only variety of such origin that 

 can be distinguished from its parent. The constant appearance of new varieties 

 makes the continuance of this work desirable. Some progress with peaches has 

 been made, but it is doubtful whether it is possible to distinguish some varieties 

 in the nursery. However, most of the nursery mixtures can be detected and 

 many thousands of misnamed peach trees have been eliminated from the trade. 



The practice of examining nurseries for trueness-to-name enters its 25th year 

 in 1945. This work is now carried on by members of the College staff under the 

 name of the Massachusetts Trueness-to-Name Inspection Service, sponsored by 

 the Massachusetts Fruit Growers' Association. 



A bulletin on pear v^arieties has been published. 



