120 



SCIENTIFIC AGRICULTURE. 



December, 1921> 



others. As a result of tlTe studies of known 

 hybrids considerable has been learned of 

 the inheritance of characters in fruits. In 

 addition the last half century has seen a 

 broadened interest in foreign fruits, and 

 many of these have been sufficiently test- 

 ed in the different regions to determine 

 their economic promise, and breeding ex- 

 periments have in part shown their pos- 

 sible value in this direction. At the same 

 time attention has also been centered upon 

 the native species. Finally the outstand- 

 ing result from the applied standpoint of 

 breeding work to date has been a deter- 

 mination of the most valuable varieties for 

 parents in many of the fruits. From the 

 economic standpoint this is of great signi- 

 ficance and importance because the best 

 parents indicate the immediate _ point of 

 attack in developing better varieties. It 

 will be seen therefore that while much 

 stands in the way of further work, much 

 has been already accomplished. 



If the above point of view is correct, 



then the method of attack which appears 

 to be most promising of results may be 

 summarized as follows: First, follow 

 through in detail the development and 

 functioning of the sex structures, noting 

 particularly the points in the life cycle 

 where essential organs are suppressed. 

 These have a direct bearing upon the pos- 

 sible combinations and upon Mendelian 

 ratios and hence upon the interpretation 

 of results. Second, study the progeny of 

 each controlled cross in the different fruits 

 carefully to determine the parents giving 

 the best progeny from the economic stand- 

 point. These will indicate the future lines 

 of work. Third, study the inheritance of 

 characteis in the available material of 

 known crosses with the view of advancing 

 the genetic knowledge of the material. This 

 knowledge will indicate the progress made. 

 All of these suggestions yjresume a know- 

 ledge of horticulture en one hand and of 

 genetics on the other — both broadly in- 

 terpreted. 



The Possibility of the Transmission by Asexual 



Propagation of the High Yielding Ability 



of Individual Apple Trees 



By M. B. 

 Assistant Horticulturist, Central 



Attention has frequently been called to 

 the fact that individual apple trees, grow- 

 ing under similar conditions and receiving 

 similar treatment, vary considerably in the 

 quantity of fruit produced. Macoun in 

 1901 called attention to the marked indi- 

 viduality of Wealt/iy, McMahon and Pat- 

 ten's Greening apple trees Avith regard to 

 yield. 



Munson dwells at some length on the 

 possibility of improving our existing var- 

 ieties simply by bud selection and says in 

 part: "If the differences in the buds of a 

 tree or other plant can be perpetuated by 

 asexual means, as by cuttings, grafting, 

 etc., it is evident that this method can be 

 depended upon for the systematic impro- 

 vement of existing varieties, and with most 

 of the commonly cultivated fruits sucli im- 

 provement is vastly more important than a 

 wholesale production of new forms." 



Some of the diverse results of latte- day 

 experiments in clonal or bud selection leave 



DAVIS 

 Experimental Farm, Ottawa. 



the field in a still unsettled condition. 

 Shamel has shown that clonal selection in 

 connection with the California navel oran- 

 ge is a practical and profitable undertaking 

 and has succeeded in isolating superior 

 types through this method. Pr(*pagation 

 from trees of known performance is the 

 practice now, rather than the promiscuous 

 propagation from not only bearing trees, 

 but nursery rows. Shamel considers that 

 there is a possibility of fruits other than 

 the citrus being improved by tliis method, 

 and says, "If this work is carried on care- 

 fully and honestly and based upon ade- 

 quate investigation of the conditions in 

 each of the varieties concerned, it Avill 

 doubtless result in as marked an improve- 

 ment in orchard production as has been 

 the case with the citrus in the oj^inion of 

 the writer. '" 



At the Missouri Station Gardner reports 

 the results from an experiment conducted 

 with scions from a high-yielding Ben Davis 



