Abschlussbericht Projekt: „Verminderung der ... - BLE

Table 1 Relationships between blackspot susceptibility (BSI, %), discolouration potential
(DP, AU 475nm ) and antioxidant activity (FRAP mmol kg -1 FM) of tubers differing in their
specific gravity (kg L -1 ) as Pearson Correlation Coefficient irrespective of cultivar, data
refer to Figure 1
Period Parameter BSI DP FRAP
Harvest 2005
Specific gravity 0.556** NS -0.261*
BSI 0.276* NS
FRAP 0.347*
Five months stored
Specific gravity 0.472** NS NS
BSI 0.287* NS
FRAP
NS
Eight months stored
Specific gravity 0.762** NS -0.410**
BSI NS -0.543**
FRAP
NS
Harvest 2006
Specific gravity 0.756** 0.398* 0.273*
BSI 0.644** 0.357*
FRAP 0.544**
Five months stored
Specific gravity 0.523** 0.383* NS
BSI 0.675** -0.389*
FRAP
NS
Eight months stored
Specific gravity 0.701** NS -0.456**
BSI 0.581** NS
FRAP 0.298*
a
Abbreviations: NS, not significantly different;** significance at p = 0.01, * significance at p = 0.05
Irrespective of the specific gravity of tubers the results of the BSI tests pointed out that the
cvs. Afra, Adretta and Granola are medium to high susceptible to blackspot after harvest
2005 (Tab. 2). The cv. Renate showed a significantly lower blackspot susceptibility compared
to cvs. Afra, Adretta and Granola. The cvs. Nicola, Lolita, Marabel and Gala were
very low susceptible to blackspot which was significant different compared to Renate. The
DP of cv. Adretta was the significantly highest compared to cvs. Granola, Afra, Lolita and
Marabel. The FRAP activities of the cvs. Afra, Adretta and Granola were significant lower
compared to cvs. Renate and Nicola. A relation to BSI was not observed because the less
susceptible cv. Marabel showed also a low FRAP activity.
The storage period of five months significantly decreased the BSI of all cultivars. Contrary
to these results, the data obtained with the DP method were similar compared to harvest
evaluation. DP and FRAP results revealed no clear classification of cultivars with respect
to their blackspot susceptibility.
After storage of eight months blackspot obtained by BSI test increased significantly in all
cultivars when compared to the data obtained after five months of storage, regardless to
specific tuber gravity. However, the BSI was not different compared to the results obtained
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