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Projekt II.1 Solbær og jordbær
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20 jordbærsorter blev i projektperioden vurderet for deres egnethed til økologisk produktion. Af alle sorter
viste ‘Honeoye’ sig at være mindst modtagelig over for gråskimmel, og den anses derfor for en velegnet
tidlig sort til økologisk produktion. I hovedsæsonen gav ‘Kent’ og ‘Cortina’ gode udbytter, om end de er
moderat modtagelige for gråskimmel. I sensæsonen var ‘Symphony’ og ‘Pandora’ relativt højtydende, selv
om de begge er modtagelige for bladpletsygdomme.
Totalt er der undersøgt 28 solbærsorter for deres egnethed til økologisk produktion. Af disse har det
foreløbig vist sig at 'Titania' og 'Intercontinental' (BRi 831515-25) er de sundeste når det gælder
svampesygdomme. 'Farleigh', som er resistent overfor knopgalmider, er desværre følsom for
svampesygdomme og har givet lave udbytte.
Der var signifikante forskelle mellem solbærsorter i indholdet af hydrocinnamiske syre derivater når
planterne blev dyrker under økologiske forhold. Tidligt i vækstsæsonen var et højt niveau af caffeoyldiquinic
syre og coumaroyl-quinic syre korreleret med sygdomsmodstandsdygtighed i solbær. Målinger af
indholdet af hydroxycinnamic syre kunne være et vigtigt redskab for at hjælpe med at vælge sunde
solbærsorter egnede til økologisk produktion.
English summary
Black currant plantings subsist for 10-12 years. During the project period the plants where produced,
planted and 1999 was the first cropping year.
During establishment all five cultivars and all four cover crops gave a sufficient nitrogen supply. The level
of nitrogen in leaves and soil and the growth were smallest in the annual cover crop treatment consisting
of vetch and rye. Powdery mildew infected ‘Ben Lomond’ very severe and caused a very little shoot
growth. Consequently the yield was very little in 1999. The four other cultivars had a yield ranging from 2
to 4 tons per ha. ‘Titania’ had the largest crop. There were no significant differences between the yield in
different cover crops.
Black currant production on legs to lighten the mechanical weed cleaning reduced the annual shoot
growth. But this did not effect the yield the first cropping year.
Infestations of aphids were smaller and leaf spot infection larger in the ‘Titania’ plants on legs. A stronger
growth in the traditional bushes, but a more dense branch structure in plants on legs probably caused this.
Mechanical weed cleaning was easier under plants on legs.
If sulphur is used to control pest in the growing season the leaf scorching and leaf discolouring increases
when the concentration of sulphur increases over 0-2-4-6-8 kg per ha. There were no significant
differences in yield but a tendency towards a lower yield when the sulphur concentration increased this
first cropping year. Sulphur treatments had a significant but not sufficient effect against mildew.
Grey mould in strawberries was tried reduces using cultural methods. Post-harvest defoliation and finger
harrowing was investigated in two cultivars. Post-harvest defoliation, though having some positive effect
on marketable yield, did not reduce the incidence of Botrytis significantly. This was the case regardless of
cut leaf material being removed from the plots or not. Finger harrowing, though in some instances having
a negative effect on yield, did not control Botrytis significantly either. However, it was clearly demonstrated
that, in organic strawberry growing, the incidence of Botrytis increases with plant age. Therefore, a shortterm
cropping system may be more important in controlling Botrytis than both post-harvest defoliation and
finger harrowing.
In a trial 20 cultivars were evaluated for their suitability in organic production. Among all cultivars,
‘Honeoye’ had the lowest susceptibility to Botrytis and is considered a good early ripening cultivar for
organic production. During mid-season, ‘Kent’ and ‘Cortina’ yielded well, although they were moderately
susceptible to Botrytis. In late season, ‘Symphony’ and ‘Pandora’ gave high yields, although they both
appeared to be susceptible to leaf spot diseases.
28 black currant cultivars were evaluated. So far ‘Titania’ and ‘Intercontinental’ (Bri 8315-25) were the
cultivars less susceptible to diseases. ‘Farleigh’ is resistant to big bud mite but unfortunately it is
susceptible to diseases and is not a high yielding cultivar.