ANNUAL REPORT, 1946-47 61 



The Culture and Nutrition of Vegetables. (W. H. Lachman.) 



1. Tomato plants grown in plots mulched with manure did not succumb to 

 foliage diseases (particularly late blight) as badly as those mulched with straw 

 or those grown without mulch. Sugar cane fibre used as a mulch continued to 

 have a marked depressing effect on the growth and yield of tomato plants. 



2. Red Cloud and Pennheart produced more early fruit than any other to- 

 mato varieties in this year's trials. Cracking of fruit has been the most impor- 

 tant factor in lowering the grade of out-door tomatoes. A rather late variety 

 named Crack-Proof was practically free from cracking this year. 



3. The variety Fordhook 242 lima bean outyielded all other varieties in our 

 trials. This variety has consistently performed well in our plots. 



4. The use of a plant hormone applied as a spray significantly increased the 

 set of greenhouse tomatoes. About 50 percent of the fruits were seedless and 

 many had objectionable air pockets where one would ordinarily e.xpect to find 

 pulp. 



5. Carotene analyses of carrots continue to indicate wide differences among 

 the varieties. Morse's Bunching and Imperator are among the highest in caro- 

 tene content. Roots of all varieties increased in carotene as the growing season 

 advanced, and roots stored for five months contained appreciably higher amounts 

 of carotene on a fresh weight basis than when they were placed in storage. 



DEPARTMENT OF POMOLOGY 

 R. A. Van Meter in Charge 



The Influence of Various Clonal Rootstocks on Apple Varieties. (J. K. Shaw 

 and W. D. Weeks.) For the fourth successive year there was frost damage in the 

 large stock-scion orchard. It requires many years to determine the value of 

 these stocks for the many varieties in cultivation. At present we believe that 

 Mailing I and II are the most desirable lor commercial orchards where the grower 

 desires trees not so tall as ordinary seedling-rooted trees. They stand winds 

 nearly as well as seedling-rooted trees, require a little less space, begin to bear 

 younger, and give larger acre yields. Mailing VII is promising but we have not 

 had as much experience with it. It is believed that Mailing XVI is superior, at 

 least for Mcintosh, but it dwarfs the trees little or not at all. Trees on Mailing 

 IX are excellent for home gardens but many require support. They are not 

 recommended for commercial orchards. 



The question of varietal adaptation is complicated and requires further study. 

 In general, the best varieties for dwarf and semi-dwarf trees are those that make 

 moderately vigorous growth. The very vigorous ones, such as Gravenstein and 

 Baldwin, tend to overgrow the stock; and the weaker ones, like Duchess and 

 Wagener, do not begin to bear much earlier than they do on seedling roots. 

 Northern Spy and Yellow Delicious are among the best varieties to grow on dwarf- 

 ing roots. 



Two papers were published in Volume 48 of the Proceedings of the American 

 Society for Horticultural Science. 



Lethal Incompatibilities Between Clonal Stocks and Varieties of Apples. 



(J. K. Shaw and W. D. Weeks.) It was reported last year that buds from shoots 

 of the normal strain G which had grown in the top of a tree of the lethal strain 



