744 EXPERIMENT STATION EECORD. fVol. 37 



berry selection (E. S. R., 33, p. 236) covering a period uf 10 years and now 

 completed also gave negative results. 



Self-fertility studies of fruits by J. C. Whitten and C. C. Wiggans confirm 

 the previous assumj)tion that certain commercial varieties of apples have a 

 tendency to self-fertility. Varieties such as Delicious, Ingram, Ben Davis. 

 Gano, and York appear to be capable of fertilizing their own flowers when 

 planted in large blocks. 



Observations made on fruit trees in connection with tillage studies by J. C. 

 Whitten and C. C. Wiggans indicate that the formation of fruit buds is induced 

 by highly concentrated sap and wood growth, and lack of fruitfulness is indi- 

 cated by less concentrated sap. In the tillage studies the tree sap was found 

 to be more concentrated in orchards where cultivation is not extensive and 

 where apparently greater competition with sod crops exists. Sap studies are 

 to be conducted for a number of years with the view of determining a possible 

 correlation between sap concentration and tillage methods. 



The studies of fruit-bud development of trees as influenced by treatments 

 and previous crops, conducteil by C. C. Wiggans, confirm the conclusion pre- 

 viously drawn that only a small percentage of the spurs blossoms two years 

 in succession and even a smaller percentage matures fruit two years in suc- 

 cession. It was found in every case where tests were nmde that the concen- 

 tration of cortex sap from bearing spurs was greater than that from non- 

 bearing spurs, if the determination was made during or soon after the fruiting 

 season. Leaf sap from nonbearing spurs shows a higher concentration than 

 leaf sap from bearing spurs. The high concentration of cortex sap from bearing 

 spurs appears to exist only while the spur has fruit on it. Later the bearing 

 spur comes back to normal concentration. So far as ob.served, there is no cor- 

 relation between the number of leaves on a spur and its fruit development 

 Spurs bearing two or more fruits show little or no difference In sap concentra- 

 tion from those bearing only one fruit. 



Examination of buds in winter for forecasting probable bloom, as made by 

 C. C. Wiggans, indicates that it is possible to forecast the probable bloom of 

 apple trees. Further observations are being made with the view of developing 

 methods of forecasting that may be used by the average grower. 



Protection of fruit against late spring frosts, A. D. I'.kki.eb (U. S. Dept. 

 Com., Com. lipts.. No. 221 (1911), p. 1101). — A consular note on a new product, 

 "ag61arine" (antifrost), said to be a vegetable derivative compounded from 

 the juices of certain plants. This material, it is claimed, has been success- 

 fully used for coating fruit trees, thereby retarding their blooming period 

 without injuring the trees. 



[Spray calendars] (New Jersey Stas. Circs. 75-79 (1917), pp. 2 each). — A 

 series of circulars consisting of spray calendars for apples and quince.s, pears, 

 sweet cherries, plums, and peaches, as above numbered, respectively. 



Blooming period of the apple in northwest Arkansas, W. H. Wicks (Ar- 

 kansas Sta. Bid. 1S4 (1917), pp. S-12, figs. 3).— This bulletin contains data col- 

 lected in 1914, 191C, and 1917 to ascertain the blooming period of different 

 varieties of apples. The work was limited to Washington and Benton Counties 

 in northwest Arkansas. Records were kept by over 300 growers each year, in 

 addition to records kept by the author. 



A study of the data as a whole shows that the relative blooming period of 

 varieties is not constant, that weather conditions preceding and during the 

 blooming period exert an Important influence on the earllness and length of the 

 blooming period, and that varieties possess different degrees of susceptibility 

 to climatic conditions. On certain sloi>es, elevations, and soils, and under cer- 



