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SWEET CHERRY PHENOLOGY

IN A NORDIC CLIMATE

M. Meland, O. Frøynes, L. Coop and C. Kaiser

Norwegian Institute for Agricultural and Environmental Research

Norway, Bioforsk and Ullensvang

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Norwegian Institute for Agricultural and Environmental Research

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Norwegian sweet cherry production

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• August is the main harvest season

• Short and relatively cool growing season

• Winter and spring frost rarely occurs

• International cultivars produce good quality fruit

• All sweet cherry orchards have rain covers

Three-wire rain cover system

Haygrove tunnels

Introduction

Phenological observations are considered to be

sensitive tools for identifying plant responses to

climatic changes. Temperature is a major determinant

of the rate of plant development and ambient air

temperature is commonly used to quantify responses.

ObjectiveOver the last 10 years the onset of the phenophases of

sweet cherry (Prunus avium L.) during the spring

tended to be earlier in Ullensvang, western Norway.

The aim of this study was to find correlations between

air temperature and biological responses of two sweet

cherry cultivars.

Sweet cherry blossom May 2007 in Western Norway

Materials and Methods

Phenological data of different sweet cultivars have been determined in the research orchard at Ullensvang Research Centre, Norway. The effects of air temperature during the winter and spring months during two 5-year periods, 1996-2000 (P1) and 2003-2007 (P2) were studied in relation to flowering of the early maturing ‘Burlat’ and mid-season ‘Van’.

The French cultivar’ Burlat’

is mature about July 10

The Canadian cultivar

‘Van’ is mature end of July

Average start of different phenophases of the

cultivars ‘Burlat’ and ‘Van’ during two periods

(1996-2000) and (2003-2007)

Average air temperature during two

periods (1996-2000) and (2003-2007) at

Ullensvang, Western Norway

Growing degree-days (GDD) during

March-April for two 5-years periods.

Base temperture is 2⁰C

Average monthly air temperatures,

Ullensvang

Temperature C°

Month Normal 2013 2014

February -0.4 -1.8 5.0

March 1.7 -1.7 5.2

April 5.2 4.7 7.7

May 10.2 10.7

Full bloom sweet cherry: 2013- May 22, 2014 – April 28

Conclusion

Increased temperatures of the spring months, March

through April speeded up flower development

significantly.