SJP84 Winter Hardy Dwarf Apple 

 Rootstock Series from Agriculture and 

 Agri-Food Canada National High Value 

 Crop Breeding Program 



Shahrokh Khanizadeh, Yvon Groleau, Audrey Levasseur, Raymond Granger, and 

 Gilles Rousselle 



Agriculture and Agri-Food Canada Research Station, St-Jean-sur-Richelieu, Quebec 



Campbell Davidson 



Agriculture and Agri-Food Canada Cereal Research Centre, Morden, Manitoba 



Apple production potential in Quebec is between 

 5.5 and 7 million bushels per annum. In 1 986 and 1 987, 

 there were severe low temperature injuries, and yields 

 were reduced to 2.8 million bushels and 4.0 million 

 bushels, respectively. This loss represents 

 approximately SI 8 million in 1986 and $12 million in 

 1987, and a concomitant increase in the volume of 

 apples imported to the province. In 1 993-1 994. similar 

 damage was reported by Quebec apple growers 

 (Khanizadeh et al., 2000a). Cold winter temperatures 

 is one of the most limiting factor in many apple-growing 

 regions, especially in Northern Central Canada when 

 the winter temperature dropped below -30°C (Granger, 

 1981; Asnong, 1 982; Khanizadeh et al., 200021. 



Cold tolerance of many plant species has been 

 extensively reviewed and studied (Chen and Li. 1980; 

 Gustaetal., 1982; Li, 1987; Sakai and Larcher. 1987 

 Khanizadeh et al., 1989a; Khanizadeh et al.. 1989b 

 Khanizadeh, 1991; Khanizadeh et al., 1992a 

 Khanizadeh et al., 1992b; Khanizadeh et al.. 1994). 

 Our previous studies have compared the concentration 

 of amino acids, protein, sugars, starch, sorbitol, N, P, 

 and K of cropped and non-cropped trees in relation to 

 cold hardiness (Khanizadeh et al., 1989b; Khanizadeh 

 et al., 1992a; Khanizadeh et al., 1994). It has been 

 shown that cropped trees that progress into the winter 

 with lower nutrient levels in their buds are more 

 vulnerable to low temperatures than those on non- 

 cropped trees (Khanizadeh et al., 1989b; 19923). 



There have been many studies of: 1 )cold resistance 

 and metabolic changes in apple woody tissue, (Brown, 

 19^8; Li, 1987; Sakai and Larcher, 1987; Khanizadeh 

 etaJ., 1989a; 1989b; 1992a; 1994), 2) types of freezing 

 injury ( Weiser, 1 970; Granger, 1 98 1 ); 3 ) breeding hardy 

 varieties or using hardy intermediate framestocks 

 (Soishnoff, 1972; Spangeloetal., 1974; Granger etal., 

 19*91; 1992; 1993); 4) inactivating icenucleating 

 bacteria (Lindow and Connell, 1984; Lindow et al., 

 19SI9); 5) use of chemical cryoprotectants (Ketchie and 

 Munren, 1976); 6) cultural manipulation to slow growth 

 and induce wood matunty in early autumn (Collins et 

 al.. 1978; Stang et al., 1978); and 7) autumn sprays of 

 grov^lh regulators to delay bud break. The use of winter 

 hardy rootstocks and \arieties, hovve\er, seems to be 

 the most desirable approach to avoid winter injury and 

 are used in international trials to screen this specific 

 trajit(Marinietal., 2001a; 2001b). 



Many reports have been published on the winter 

 hardiness and survival of selected rootstocks (Granger 

 et al., 1993; Doroshenko et al., 1995; Skrivele et al., 

 19*95; Fisher & Fisher, 1996; Yang etal., 1995; Witney, 

 19*96; Khanizadeh et al., 2000a; Khanizadeh et al., 

 20<00b; Marini et al., 2001a; Marini et al., 2001b; 

 Webster, 2003). Alnarp 2 (A2) was reported to have 

 the highest survival rate when exposed to low soil 

 temperatures, followed by MM.104, Antonovka, M.26, 

 MM. Ill, M.4, MM. 106, M.9, and M.7, respectively 

 (Zagaza, 1977). 0.3 and 0.8 were reported to be 



14 



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



