l'.>i'Ol HORTICULTURE. 045 



usually following summer pruning, isi cUu' lo (lie increased water supply or tlie 

 mineral initriciit .supply, espt'Cialiy nitrogen, afforded tlie remaining shoots, 

 thereby enabling a more complete use of carbohydrates, as observed by Kraus 

 and Kraybill in their work with tomatoes (K. S. K., 40, p. 40). The evidence 

 secured tends to show, however, that this more complete utiiizati(m of carbo- 

 hydrates for top growth takes place at the expense of root development; hence, 

 unless the pruning is repeated, there will come a time when th(» reduced 

 transpiration due to previous pruning will be balanced by reduced root growth, 

 and increased vigor will cease to be evident. 



All types of pruning have a dwarfing effect and tend to reduce fruit pro- 

 duction on young trees, primarily because of the reduction in the size of the 

 tree. With species bearing fruit from spurs, the reduction in yield is greater 

 than for species bearing fruit on laterals or one-year twigs. Thus far pruning 

 lias not affected the yield through any marked stimulating effect on fruit-bud 

 i'ormalion or twig growth. 



The status of orchard fertilization experimentation, W. H. Aluekman 

 {Proc. Amci: Soc. Hort. ScL, 16 (1919), pp. 109-113).— A contribution from the 

 Minnesota Experiment Station briefly summing up the results of various in- 

 vestigators relative to orchard fertilization. 



Methods of interpreting results in orchard fertilizer experiments, R. D. 

 Anthony {Proc. Amer. Soc. Hort. Sci., 16 {1919), pp. 113-117). — A contribution 

 from the Pennsylvania Experiment Station discussing methods of interpreting 

 fertilizer results which the author has found of value in his own work. 



Observations on characters of forms of Malus, C. S. Ckandall {Proc. 

 Amer. Hoc. Jlort. ScL, 16 {1919), pp. 131-135).— A contribution from the Uni- 

 versity .of Illinois comprising a general discussion of character variations 

 observed in Fi seedlings of apple crosses. 



The apple cross TolmanX Malus Toringo, C. S. Ciiandai.t. {Proc. Amer. 

 Soc. Hort. Sci., 16 {1919), pp. 60-66).— A contribution from the University of 

 Illinois in which are considered a group of apple seedlings resulting from a 

 cross of Tolman. a well-known standard variety, as the pistillate parent and 

 a dwarf form of Malus Toringo {Punis sichohlii) as the pollen parent. 



The outstanding fact regarding this group of seedlings is the extent of the 

 domination of the dwarf, small-fruited male parent and the corresponding sup- 

 pression of resemblance to the mother plant. Those characters that occupy 

 intermediate positions between the parents are not median, except as to 

 tlower expansion, but are mtieh nearer the male than the female plant. 



Self-sterility and cross-sterility in the apple, J. W. Gowen {Maine Stn. 

 liul. 287 {1920), pp. 6/-8S).— This bulletin presents and discusses data showing 

 the effect of self- and of cros.s-pollination on the yield of marketable fruit with 

 IG varieties of apples, and also summarizes similar data secured from a large 

 number of varieties by various investigators. A list of consulted literature 

 is given, and additional data showing the size of apples, together with the 

 number of good and poor seed secured from the selfing and crossing of varieties, 

 are appended. 



The results of the investigation as a whole show that most varieties of 

 apples are more or less self-sterile in the case of varieties that are to some 

 extent self-sterile. No difference is noted in the fruit set when a variety is 

 self-pollinated, when it is pollinated with the pollen fronr different flowers on 

 the same tree, or when It is pollinated with i>ollen from different trees of the 

 same variety. Summing up the investigations dealing with sterility In apples, 

 out of 119 varieties only 42 set fruit, and only 1.5 of these had a set of fruit 

 which was even moderately conimercially profitable. Most varieties are capable 

 of ready cross-fertilization with the pollen of other varieties. Over three- 



