hardier than M.26 and MM. 106 (Heeney, 1981), and 

 Bugadovsky was reported to be as hardy as M.26 

 (Czynczyk, 1979). 



A part of the Agriculuire and .Agri-Food Canada 

 (AAFC) National High \alue Crop (NHVC) breeding 

 program is devoted to de\elopment of adapted, dwarf 

 and semidwarf, winter-hardy, and disease-resistant 

 apple rootstocks. The original rootsiock-breeding 

 program began in early 1950 in Ottawa. Ottawa 3 (0.3) 

 was the first commercialK released clonal rootstock, 

 released in 1974 from this National program, and the 

 rest was send to Quebec for further testing along with 

 others developed in Ottax'.a and in Manitoba. 



The identification of new, well adapted, winter- 

 hardy, disease-resistant apple rootstocks that propagate 

 easily will have a direct impact on the apple industry 

 in the northern U.S. and in Canada by reducing 

 production fluctuation caused by cold-temperature tree 

 damage. 



Materials & Methods 



Several crosses were made in 1975 including 

 Mains robiista R-5 with M.26 or with Budagovsky 

 579490, and also some seeds was collected from open 

 pollinated 0.3. Seeds were germinated under 

 greenhouse conditions and planted in a nursery in 1980. 

 Budding to Spartan was conducted in Ii982, and trees 

 with bud failure were cleft-ijrafted in 1983. All trees 



were planted in 1984 (5.5 x 3.0m) at the experimental 

 farm of AAFC in Frelighsburg, Quebec. Standard 

 orchard management practices were applied each year 

 (Anon., 1976). Of the 908 trees started in 1984, only 

 499 were used for evaluation and the rest eliminated 

 from the program due to their lack of winter hardiness, 

 disease susceptibility, or other undesirable characters, 

 like extreme difficulty to propagate in stool bed. Data 

 are shown only for those nine superior rootstocks 

 (Table 1 ) which have not shown any w inter injury since 

 1984 and were not eliminated for other reasons. 



Trunk circumference was measured at 25 cm abo\ e 

 the graft union and used to calculate trunk cross- 

 sectional area in 1990. Yield and incidence of root 

 suckers were recorded annually from 1988-1990. Tree 

 height and spread were measured as the maximum 

 vertical extension of the tree and the maximum 

 horizontal extension of the canopy, respectively (Table 



1). 



Two other sites were also established to examine 

 the ease of propagation and suitabilit> of the rootstocks 

 for commercial grafting compare to M26, M9, and 0.3 

 (data not shown). 



"Summerland Mcintosh' was used as scion for the 

 nine superior rootstocks (Table 2). They were planted 

 in four selected locations including L'Acadie (AAFC, 

 Experimental site) and also tested under controlled 

 conditions at two commercial grower sites Dunham 

 and Mont St-Gregoire (Verger Dupuis Inc., 587 Hudon, 



Fruit Notes,"Volume 68, Spring, Summer, & Fall, 2003 



15 



