740 EXPERIMENT STATION RECORD. [Vol.40 



different proportions. The results secured with the lettuce plant have shown 

 that the nitrogen content of the plant can be varied widely by various fer- 

 tilizer treatments. When nitrogen, phosphorus, and potassium in equal parts 

 were compared with manure containing three times the nitrogen in the fer- 

 tilizer, it was found that soils will respond to applications of manure up to 

 2." tons of dry manure per acre applied three times per year, while one-third 

 the nitrogen in 15 tons of dry manure applied with equal phosphorus and 

 potash prevents the development of normal plants. The various comhinations 

 used have shown that in greenhouse forcing, manure is undoubtedly the most 

 satisfactory fertilizer. Leaf moid containing equal quantities of organic mat- 

 ter is not so available and shows no results until the second year. A combina- 

 tion of complete fertilizers with less manure may he :is satisfactory as manure 

 alone, and a fertilizer made up of dried blood, dicalcium phosphate, and 

 potassium chlorid will produce good crop increases, 



[Investigations with fruits and vegetables] [Minnesota Sta. Rpt. 1918, pp. 

 60-62, 68, 6}). — Brief statements of progress made in various lines of work are 

 given. 



In the fruit sterility studies, all the plums which have been self-pollinated 

 have been found to be self-sterile. The Investigation has shown that there are 

 three distinct periods of dropping in the plum. The first flowers to drop have 

 aborted pistils. The next drop occurs three or four weeks after bloom through 

 lack of fertilization. Tin' so-called "June drop" occurs about three weeks later 

 as a result of embryo abortion. 



Considerable attention has been given to devising a method of determining 



the relative hardine - of fruil a Hit gs. The results of these studies show that 



the winter injury to the tetiderest tissues of the plant serves as an accurate 

 index of hardiness The results of the tests of trial plats at Deerwood, Grand 

 Rapids, and Cloquel show that in the raspberry only a very few of the varie- 

 ties in the nursery trade are sufficiently hardy to stand the winter in the north- 

 ern section of the State uncovered, and only m few of them are hardy when 

 covered. Tests are being made of seedlings from seed obtained from Canada. 

 The present status of general varieties of fruit tinder observation is briefly 

 noted. 



In the work with vegetables, distinctive strains of beans, varying in size and 

 shape, productiveness, color, ami brlttleness of pod. have been isolated from 

 the Refugee bean " 1,000 to 1 " and are being propagated for stocks of seed. 

 Improved strains of the Alaska pea have also been developed, a number of 

 selected strains of Hubbard squash are being tested. First feneration tomato 

 crosses again proved more productive than their parental mean and often 

 more productive than the highest yielding parent. 



[Report of horticultural investigations] (Washington Sta. Hul. 158 [1919), 

 pp. 22-24). — Brief statements of progress made in various lines of work are 

 given. 



In a sterility test of Jonathan and Rome Beauty apples, both varieties "sei 

 a few fruits without cross-pollination, when pollinated by the normal fall of 

 pollen and distribution of pollen and by the WOTB of bo-.." The fruits set on 

 these trees contained very lev, seeds and a large proportion of seeilless apples. 

 Jonathan in the open orchard averaged 7 seeds per apple and Koine Beauty 

 in seeds per apple. There was no appreciable difference in the size or api>ear- 

 ance of the self-pollinated fruits and those produced in the open orchard. 



In the breeding work with blackberries and raspberries, no plants UlUS far 

 fruited are worthy of introduction as a new variety. Seedlings of Evergreen 

 blackberry were the only ones that came true to type. A study of soil moisture 



