80 Maine Agricultural Experiment Station. 1920. 



given an even start the growth of the pollen tube in the style of 

 the compatible pollen is so rapid as compared with the growth 

 of the pollen tube of the incompatible pollen that in the major- 

 ity of cases the compatible pollen would beat out the incom- 

 patible pollen in the fertilization of the ovule. Such a competi- 

 tive race is, of course, eliminated in experimental work where 

 the incompatible pollen and that only is allowed to grow in the 

 style. Should it be assumed, however, that the number of fruit 

 matured for the other stations is more representative of the 

 percentages matured for the Maine Ben Davis orchards even 

 this percentage (it is only about 1.5) will not account for the 

 crop of fruit obtained in some of the favorable apple years, when 

 this fruit is all of excellent size and color. These facts all 

 strengthen the conclusions as expressed above and as demon- 

 strated by controlled experiment in Arkansas that the color of 

 the fruit, the size and other characteristics of the variety are as 

 pronounced in the apple resulting from cross fertilization as 

 they are from the apple resulting from self fertilization. 



It may therefore be safely concluded that the data on cross 

 fertilization in the apple show that an increased yield results 

 and the size, color and quality of the apples are equal to those 

 from self pollination. To be commercially desirable an orchard 

 should, therefore, be a mixture of the varieties which have com- 

 patible pollen. 



This conclusion may seem contrary to what is considered 

 good commercial practice which has in the past favored large 

 blocks of a single variety of apple. As shown above by results 

 only recently determined, the apple tree must be crossed fer- 

 tilized to produce good, regular crops of commercially desirable 

 fruit. By this it is not meant that an orgy of promiscuous re- 

 grafting or planting of many varieties in one block is advocated. 

 It means simply that two varieties which are reciprocally com- 

 patible should be planted together. The trees for pollination 

 may be reduced to a minimum of only 5 per cent or one tree in 

 20. In planting every fourth tree in each fourth row is the 

 pollenizer to accomplish this result. Promiscuous grafting is 

 likewise bad commercially since it makes harvesting especially 

 difficult. If it is desired to grow the varieties in equal propor- 

 tions alternate blocks of not more than 4 or 5 rows may be 



