sodininkystė ir daržininkystė 25(4)

hardiness index. Other rootstocks that had good hardiness indices include M.9Emla,
CG6179, M.26Emla and P 2. Differences in cold hardiness are evident between
rootstocks but also between the various components used to calculate overall hardiness.
Rootstock mortality (LT 20
) was highest for M.4 and G.16 and lowest for
KSC28, G65, M.9Emla, M.26Emla, P 2, CG6179 and B.118. Root volume increase
was the most sensitive to cold injury while both incremental increases in new
shoot growth and trunk diameters were quite similar in their sensitivity. CG6179,
M.9Emla and M.26Emla had a 50% reduction in root growth at temperatures between
-11 and -12°C (RT 50
) while B.9 and A.2 reported the same reduction at
temperatures between -4.7 and -5.3°C (Table 1). To validate our results we compared
our laboratory results with those from the 2004 test winter from the Champlain
Valley of New York in 2004. A good correlation was found between the field
tree survival data and our controlled freezing results (r = -0.70) (Fig. 1) thus
indicating a good fit.
Table 1. Whole plant rootstock screening
1 lentelë. Poskiepio testavimas
Rootstock
Poskiepis
New shoot
growth
Naujø ûgliø
augimas
(RT 50 , °C)
Trunk diameter
increase
Kamieno
padidëjimas
(RT 50 , °C)
Root volume
increase
Ðaknø tûrio
padidëjimas
(RT 50 , °C)
Mortality
Žuvimas
(LT 20, °C)
Hardiness index
Atsparumo rodiklis
(°C)
A.2 -10.9 -13.8 -5.3 -11.8 -10.4
B.9 -9.7 -10.7 -4.7 -10.7 -9.0
B.118 -12.6 -11.0 -8.0 -12.0 -10.9
CG179 -13.5 -13.3 -12.3 -12.4 -12.9
CG202 -9.7 -10.8 -7.7 -11.1 -9.8
CG210 -14.1 -13.2 -8.5 -11.1 -11.7
G.16 -12.7 -13.0 -9.4 -9.8 -11.2
G.30 -12.6 -13.1 -8.8 -11.8 -11.6
G.65 -14 -9.6 -9.9 -12.9 -11.6
KSC28 -16.9 -16.5 -9.4 -14.1 -14.3
M.26 -11.4 -15.0 -6.5 -12.1 -11.3
M.26EMLA -13.0 -14.2 -11.3 -12.6 -12.8
M.27 -12.9 -9.5 -5.3 -12.4 -10.0
M.4 -7.9 -10.6 -5.8 -8.2 -8.1
M.9 -13.4 -12.5 -5.2 -11.1 -10.6
M.9.EMLA -14.5 -14.3 -11.9 -12.7 -13.3
P 2 -13.4 -14.4 -9.8 -12.5 -12.5
99