Breeding and Improving Ornamentals 



By a. F. Yeager, E. B. Risley, E. M. Meader, and R. B. Pike 



Azaleas 



The breeding work with the group of rhododendrons which are known as 

 azaleas has three objectives: 1. The production of superior seed propagated 

 strains of our three native New Hampshire azaleas, 2. The production of 

 azaleas roughly equivalent to the Ghent and Mollis hybrids that will be 

 reliably hardy in northern New England, and 3. The production of azaleas 

 akin to the semi-evergreen types that should be hardy in at least part of 

 New Hampshire. 



1, Rhodora {Rhododendron canadense Torr.), June Pink iR. roseum 

 Rehd.) and Swamp Honeysuckle (/?. viscosum Torr.) are our three native 

 New Hampshire azaleas. All three are excellent garden plants in their su- 

 perior forms. Since there is no practical means of vegetative propagation, 

 presently known, it is necessary to try to produce strains of enough genetic 

 purity to make seed propagation satisfactory. A deep colored, wide petaled 

 selection of Rhodora upon selfing has produced even more attractive off- 

 spring and a selection of these has in turn been selfed. The resulting seed- 

 lings have not yet bloomed. It is hoped that this process of selfing can be 

 continued until a high percentage of the seedlings are superior. However 

 as Rhodora is one of the rare tetraploid azaleas this process may be long. 

 In the meantime the possibility of vegetative propagation is being more 

 fully explored. 



A superior wild selection of June Pink {R. roseum) has been selfed and 

 200 progeny have been grown. These plants display considerable vegetative 

 variation and it is thus assumed that there may be a comparable variation 

 in flower color, form, cluster, size and scent from which further selection 

 and breeding may be continued. Two plants with the highly desirable 

 character of stoloniferous growth have already been selected for future 

 breeding. 



The Swamp Honeysuckle {R. v'scosum) is still in the stage of first se- 

 lection and a few hundred plants are being grown from collected seed to 

 locate a superior plant or plants. Seed reproduction of superior forms will 

 be attempted with this azalea as with the two former ones. R. roseum and 

 R. viscosum are both diploids and if self fertility can be maintained a sat- 

 isfactory degree of genetic purity may be more easily achieved than with 

 R. canadense which is tetraploid. 



2. In the second area of azalea breeding, i.e., the production of hybrids 

 comparable to the Ghent and Mollis azaleas, we are using as parent stock 

 only those species and individuals which are either native to New Hamp- 

 shire or have demonstrated their hardiness here. 



