Volume 5 Special Issue 1 2011
Plant Science and Biotechnology in Norway

How to reference: Lombnæs P, Bævre OA, Vagstad N (2011) Norwegian Agriculture: Structure, Research and Policies. In: Nestby R (Ed) Plant Science and Biotechnology in Norway. The European Journal of Plant Science and Biotechnology 5 (Special Issue 1), 1-4

Guest Editor

Rolf Nestby

Bioforsk, Norway

www.bioforsk.no/ikbViewer/page/home

CONTENTS AND ABSTRACTS

Peder Lombnæs, Olav Arne Bævre, Nils Vagstad (Norway) Norwegian Agriculture: Structure, Research and Policies (pp 1-4)

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Research Note: Norway has a land area of 324.000 km²; 3% of the total land area is cultivated, which constitutes 1 million ha. Agricultural production takes place in all parts of the country under highly variable climatic conditions. Most of the cultivated land is used for grass (65%) and cereal (30%) production. Even if the size of the arable land has been mainly stabile the last decades, there have been a decreasing number of active farmers. The organisation of higher education and applied research in agriculture is divided between universities and research institutes. Bioforsk – the Norwegian Institute for Agricultural and Environmental Research – is a national research institute under the Norwegian Ministry of Agriculture and Food and it is the dominant institute in agricultural research. The main overall areas of competence in Bioforsk are agricultural and environmental research, and innovation based on the utilization of land resources. This includes research and development within (i): Multifunctional and sustainable agriculture including rural development, (ii): Plant science, plant protection and bio-technology, and (iii): Environmental protection and natural resource management. The Norwegian agricultural policy has close relationships with the regional policy, rural development and settlement at the countryside. There has been a long-term goal to maintain agriculture in all parts of the country. The agricultural policy has comprehensive systems of agricultural subsidies with little export and little import of competing agricultural products. Multifunctionality of agriculture is an important part of the Norwegian agricultural policy, emphasizing social and environmental sustainability in the agricultural mode of operation. Food security and rural activities represent the sound basis that has given long-term legitimacy to the agricultural policy.

Rolf Nestby (Norway), David Percival (Canada), Inger Martinussen, Nina Opstad, Jens Rohloff (Norway) The European Blueberry (Vaccinium myrtillus L.) and the Potential for Cultivation. A Review (pp 5-16)

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Invited Review: Blueberries belong to the genus Vaccinium, a widespread genus with more than 200 species of woody plants. In Northern Europe, the European blueberry (EB), also called bilberry, is one of the most important wild berries. EB (Vaccinium myrtillus) is very demanded by the processing industry, due to its delicious taste and high dietary value. However, to our knowledge there has been made no efforts of domestication of the species, and it is still harvested in forest fields without any cultivation. The successful management of the sweet lowbush blueberry (V. angustifolium), which in many ways is similar to the EB, suggests that there are opportunities to increase yield and decrease the significant yearly variation in EB yield, by practices including fertilization, irrigation, cutting trees, and weed control. The fruit yield in wild stands of EB is very variable, but the potential is probably close to 2 tons per hectare. Results from literature on growth of the EB, development and ecology are discussed in relation to possibilities for domestication.

Jens Rohloff (Norway) Impact of Agricultural and Environmental Factors on Strawberry (Fragaria x ananassa Duch.) Aroma – A Review (pp 17-34)

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Invited Review: The cultivated strawberry (Fragaria x ananassa Duch.) is an important berry crop worldwide due to its flavourful taste, and high content of nutrients and health-beneficial phytochemicals. Derived from interspecific hybridization of the octoploids F. virginiana and F. chiloensis, a vast number of strawberry varieties have been developed adopted to varying growth environments, and in order to meet consumer demand and preferences by the food industry. Hitherto, more than 360 volatile aroma compounds have been described in varietal genotypes, thus underscoring the complexity of aroma patterns in strawberry comprising hydrocarbon acids, esters, alcohols, aldehydes, and ketones, terpenes, aromatic structures, and furanones. Different extraction and analysis techniques, among others gas chromatography (GC), and sensory evaluation, which all are applied in the quality assessment of strawberry fruit, are presented. The impact of varietal and genetical differences, agricultural and environmental factors, post-harvest conditions and processing on strawberry aroma content and composition is highlighted by numerous examples from own research studies utilizing solid-phase microextraction (SPME) coupled with GC. The significance of inheritance and aroma compound metabolism on allover strawberry quality is emphasized with specific focus on future breeding efforts in Fragaria sp.

Gunn Mari Strømeng, Arne Stensvand (Norway) Godronia Canker (Godronia cassandrae f. sp. vaccinii) in Highbush Blueberry (pp 35-41)

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Invited Review: Godronia canker, caused by the fungus Godronia cassandrae f. sp. vaccinii, may cause severe stem dieback in highbush blueberry (Vaccinium corymbosum), and it is especially damaging in young plantings. This paper is an overview of presently available literature on taxonomy, biology and epidemiology of G. cassandrae f. sp. vaccinii, and management options of the disease. The pathogen has been reported from highbush blueberry growing areas in North America and in Northern and Central Europe. The pathogen overwinters in cankers or infection sites on young stems. Symptoms become visible in spring as reddish brown lesions that enlarge progressively, and eventually may girdle and kill the stems. The sexual stage has been found in North America, but not in Europe. However, the imperfect stage seems to dominate on both continents. Pycnidia are produced abundantly in the lesions, and conidia may be spread by rain splash from early spring to late autumn. The peak period of conidia formation has mostly been reported to occur in spring and early summer. Infections mainly take place in spring and autumn. Control measures include use of healthy planting material, use of cultivars with high resistance, and pruning and burning of infected stems. There are no fungicides available that sufficiently control the disease, and it is difficult to optimise the timing of fungicide applications.

Anita Sønsteby, Ola M. Heide (Norway) Environmental Regulation of Dormancy and Frost Hardiness in Norwegian Populations of Wood Strawberry (Fragaria vesca L.) (pp 42-48)

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Original Research Paper: Effects of temperature and photoperiod on plant dormancy development and cold hardiness were examined in six latitudinal and altitudinal populations of wood strawberry (Fragaria vesca L.). Following exposure to natural seasonal changes and/or artificial manipulation of the plant environment, the degree of dormancy was essayed by forcing plants at 20°C and 20 h photoperiod, while cold hardiness was essayed by artificial freezing. Dormancy development in plants grown outdoors under natural autumn temperature and daylength conditions at 61°N differed greatly in two successive years with contrasting temperature conditions. When temperature was relatively high during late October and the first half of November, the plants attained the deepest state of dormancy by late November, while low temperature during the same period resulted in a gradual loss of dormancy throughout autumn. The responses of plants grown at controlled temperatures, likewise confirmed that relatively warm conditions are required for SD dormancy induction in wood strawberry. The capacity for runner formation and petiole elongation were identified as the most sensitive criteria of the state of dormancy. Growth vigour and flowering generally decreased with increasing latitude of population origin. Development of frost hardiness required exposure to short days (SD) and near-freezing temperatures for several weeks. Non-hardened plants grown at 18°C and 18-h photoperiod, were all killed at -12°C (all surviving -6°C), regardless of population origin. However, hardened plants exposed to natural out-door conditions for 10 weeks from September 27 to December 5 all survived freezing at -15°C, many at -18°C, and some even at -21 and -24°C. In such hardened plants there was a clinal increase in frost hardiness with increasing latitude of population origin. The results are discussed in relation to results with cultivated strawberry.

Anne Kari Bergjord, Annbjørg Øverli Kristoffersen, Ragnar Eltun (Norway) Growth Potential and Course of Frost Tolerance in Winter Wheat (Triticum aestivum L.) as Influenced by Variable Temperature and Snow Cover Conditions (pp 49-54)

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Original Research Paper: The anticipated future changes in temperature, precipitation and snow cover caused by global warming may affect winter survival of autumn sown wheat. More variable weather conditions may cause an increased frequency of periods with alternating freezing and thawing and less stable snow covers. In the present study, the course of plant frost tolerance and growth potential was studied by exposing cold acclimated plants of winter wheat to conditions with alternating periods of freezing and thawing (either –1 or +5°C), and differing durations of snow cover. Tests of frost tolerance and determination of growth potential were performed each time the temperature or snow cover conditions were changed. Periods without snow cover and +5°C caused dehardening, with loss of frost tolerance being more pronounced during the first dehardening period than in the second one. The ability to reharden after a dehardening period decreased towards the end of the experimental period. Mild periods during winter also seemed to exhaust plant growth potential, possibly by increasing respiration rate while photosynthesis was still restricted. The results indicate some of the challenges we may face regarding overwintering of winter wheat in a future climate.

Tor J. Johansen (Norway) Influence of Temperature and Day-length on Dormancy in Seed Potato cv. ‘Asterix’ (pp 55-61)

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Original Research Paper: Dormancy in a potato tuber prevents sprout growth even under optimal sprouting conditions and is the first stage in the physiological ageing process. The intensity and duration of this phase differs between genotypes (cultivars) and may also be affected by environmental conditions both during tuber bulking and early storage. The current study aimed at finding how simulated high latitude growth conditions influence dormancy and the physiological age of tubers to be used as seed potatoes. In a controlled climate at natural light conditions, tubers grown at a low temperature (9°C) had 2-3 weeks shorter dormancy than tubers grown at higher temperatures (15 and 21°C). In tubers grown at artificial light conditions, day-lengths (12, 18 or 24 h) did not affect dormancy significantly. A post-harvest treatment with a low temperature (one month at 4°C and subsequently 18°C) reduced dormancy by 2-3 weeks in tubers from the highest growth temperatures (15 and 21°C) in comparison with constant 18°C post-harvest. After the lowest growth temperature (9°C) the duration of dormancy was not affected by post-harvest temperature treatments. Physiological age was determined by sprouting characteristics after winter storage. At this stage the sprouting capacity was highest in tubers originating from the lowest and the highest growth temperatures. Further, the number of sprouts per tuber was higher in tubers grown at 9°C than at 15 or 21°C. These results were not correlated with duration of dormancy after the various treatments, suggesting that temperatures may affect dormancy and physiological ageing independently. The present results show that dormancy may be shortened by low grow temperatures, and similarly by low post-harvest temperatures at higher growth temperatures.

Aksel Døving (Norway) Modelling Sweet Cherry (Prunus avium) Fruit Yield in Norway (pp 62-66)

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Original Research Paper: Data from commercial sweet cherry growing in two regions of Norway were collected, and the relationship between yield and climate data was studied. Data were obtained from the two regions Ullensvang and Valldal, both in the fjord district of Norway. For Ullensvang two reliable datasets were available; one from Gartnerhallen 1963-1991 and one from three packing houses 1955-2002. The third dataset was from Gartnerhallen in Valldal 1954-2001. The relationship between relative yield levels as a percentage of a moving average and climate data was studied. The long time series and reliable datasets for Ullensvang made a good basis for statistical calculations. Multiple regression equations with meteorological data as predictors were developed for predicting yield per June 1^st and for explaining yield after harvesting. The predictors and their coefficients in the regression models might explain the effect of weather on yield. Yield level was positively correlated to temperatures in July-September in the year previous to the fruiting year. Yield was negatively correlated to number of sun hours in November-December and to temperatures in January-February. Warm and dry weather during flowering in May was favourable for yield. Much rain in May reduced yield; 1 mm more rain in May reduced yield 0.25%. Much rain and high humidity in June or July had a negative influence on yield level; one more day with precipitation in July reduced yield with about 3% in Ullensvang. Climate factors before June 1^st had a strong influence on yield, making it possible to develop multiple regression models to predict yield levels. Such models for predicting yield can be very useful for both growers and marketing.

Mekjell Meland (Norway) Effects of Different Blossom Densities and Crop Loads of ‘Aroma’ Apples (Malus x domestica Borkh) on Yield, Fruit Quality and Return Bloom (pp 67-71)

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Original Research Paper: Ten-year-old ‘Aroma’ on M26 rootstock were thinned when the first flower opened and at 20 mm fruitlet diameter to establish four different crop loads ranging from heavy crop load to fully deflowered. The planting distance was 1.4 × 4 m in single rows, shaped as slender spindle trees and limited to 2 m height by pruning. The manual-adjusted crop load treatments [0, 2, 4 and 6 fruits per cm² trunk cross sectional area (TCSA)] were applied over three consecutive seasons on the same individual trees. At harvest, mean yield per tree thinned at bloom varied from 0 to 23 kg and the mean fruit weight ranged from 114 g in the heaviest cropping treatment thinned at fruitlet, to 233 g in the lightest cropping treatment thinned at bloom. There were significant differences between the different treatments in final fruits per cm² TCSA and fruit set. Thinning at bloom to different crop levels gave a significant lower fruit set than thinning at the fruitlets stages to the same levels the first year. Thinning at fruitlets gave smaller fruits at the same crop level compared to bloom thinned. Fruit weight and soluble solid contents were largest at lowest crop load and decreased with increasing crop. Light cropping trees resulted in advancing of fruit maturity as indicated by less firmness and starch content. Seed amounts per fruit increased significantly by delayed thinning. Return bloom was more promoted when thinned at bloom. In conclusion, thinning to 6 fruits per cm² TCSA at bloom yielded annually large fruits of high quality. By thinning at fruitlet stage, the crop load must be reduced to 4 fruits per cm² in order to obtain similar results.

Inger Martinussen (Norway), Vladimir Volodin, Svetlana Volodina (Russia), Eivind Uleberg (Norway) Effect of Climate on Plant Growth and Level of Adaptogenic Compounds in Maral Root (Leuzea charthamoides (Willd.) DC.), Crowned Saw-wort (Serratula coronata L.) and Roseroot (Rhodiola rosea L.) (pp 72-77)

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Original Research Paper: Maral root (Leuzea charthamoides DC), roseroot (Rhodiola rosea L.), and crowned saw-wort (Serratula coronata L.) were grown in a phytotron under controlled conditions at 9, 15, 21°C day/9°C night and 21°C. All these treatments had 24 hours of light (long day-LD). In addition there was one treatment at 21°C with only 12 hours of light (short day-SD). Plants were harvested after four months and plant growth was recorded. Leaves of S. coronata and the underground part of L. carthamoides and R. rosea were dried and analyzed for adaptogenic compounds. The number of shoots and dry weight of caudex with roots of R. rosea increased by raising the temperature from 9 to 15°C. Differentiated day and night temperature with an average temperature of 15°C further increased the growth. The lowest number of shoots and the lowest dry weight of roots were produced at the highest temperature (21°C). The concentration of tyrosol and cinnamic alcohol in dried R. rosea roots and rhizomes was significantly affected by temperature and the highest levels were achieved at the lowest temperature, and the northernmost clone had the highest content of adaptogens at all temperatures compared to the southern clones. Growth of L. carthamoides leaves and underground part was the best at the two intermediate temperature treatments, while S. coronata seemed to prefer warmer temperatures and produced most leaves at 21°C. At 21°C, short days had negative effect on growth of all three species. The levels of ecdysteroids were significantly affected by temperature in both roots of Leuzea and of Serratula leaves with the highest levels at the intermediate (15°C) temperature.

Linda Gordon Hjeljord, Gunn Mari Strømeng, Arne Tronsmo, Anita Sønsteby, Arne Stensvand (Norway) Attempts to Reduce Strawberry Grey Mould (Botrytis cinerea) in Norway Using Fungal Antagonists (pp 78-85)

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Original Research Paper: Grey mould (causal agent Botrytis cinerea) is the most serious disease of field-grown strawberries in Norway. As this disease has become increasingly difficult to control with chemical fungicides, alternative control measures based on application of commercially available or laboratory strains of antagonistic fungi were investigated in field trials at eight locations in Norway. Formulated or unformulated strains of Trichoderma spp. and Clonostachys roseum were applied during flowering using sprays (10³-10⁶ conidia ml^-1) or bumblebees (Bombus terrestris). At harvest, the incidence of grey mould on untreated plants varied from 4 to 70% at different trial sites and was positively correlated with the amount of precipitation during harvesting (P < 0.001). The biocontrol treatments did not reduce disease at any location. A bioassay was used to assess the ability of the tested antagonists to prevent flower infection by B. cinerea under controlled conditions (high humidity, low or high temperatures, various antagonist concentrations). All antagonist strains prevented infection at 25°C at a spray concentration of 10⁶ conidia ml^-1. However, at 15°C, which was the mean temperature during field trials, at least 10⁸ conidia ml^-1 of the antagonists were required to provide significant disease control. These results imply that the recommended concentrations of these antagonists are insufficient to prevent flower infection by B. cinerea under disease-conducive field conditions of high humidity and cool temperatures.

Venche Talgø, Leif Sundheim, Halvor B. Gjærum, Maria Luz Herrero, Aruppillai Suthaparan, Brita Toppe, Arne Stensvand (Norway) Powdery Mildews on Ornamental Trees and Shrubs in Norway (pp 86-92)

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Original Research Paper: This paper presents powdery mildew species recorded on woody ornamentals, with special emphasis on the latest arrivals; Erysiphe flexuosa on horse chestnut (Aesculus hippocastanum), Erysiphe syringae-japonicae on lilac (Syringa vulgaris) and Podosphaera spiraeae on white spirea (Spiraea betulifolia). The two former were found in 2006, while the latter was first detected in 2008. Chasmothecia (formerly named cleistothecia) were not found on white spirea until 2010. Several locations seemed to have optimal conditions for development of powdery mildew diseases in 2006. That year the long established Sawadaea bicornis on sycamore maple (Acer pseudo-platanus), was found for the first time on tatarian maple (Acer tataricum ssp. ginnala) and one cultivar from hedge maple (Acer campestre ‘Red Shine’). Also several species and cultivars of Rhododendron had massive attacks of powdery mildew in 2006. In 2010, chasmothecia of E. azaleae were found on severely affected R. ‘Magnifica’ in western Norway. Most powdery mildew species are host specific, but especially Phyllactinia guttata has a wider host range, e.g. hazel (Corylus spp.) and common ash (Fraxinus excelsior).

Lars Sekse (Norway), Ursula Wermund (Norway/UK), Rajko Vidrih, Marjan Simčič (Slovenia), Eivind Vangdal (Norway) Fruit Firmness as Related to Quality Attributes in Two Plum Cultivars (Prunus domestica L.) of Different Maturity (pp 93-97)

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Original Research Paper: Fruit of the multicoloured plum cultivars ‘Opal’ and ‘Victoria’ were sorted into three maturity groups MG1, MG2 and MG3 according to their visual surface colour combined with firmness as evaluated by fingers. Fruit firmness was measured by penetrometers Durofel^® and PNR 10^® and by sensory evaluation. ‘Victoria’ had larger fruit and lower soluble solids content than ‘Opal’. Durofel^® values indicated that ‘Victoria’ had firmer fruit than ‘Opal’, while PNR10^® measurements did not discriminate statistically between cultivars. All firmness measurements, both instrumental and by sensory evaluation discriminated highly significant between MGs within each cultivar. SSC increased over the three maturity groups in both cultivars. All measured colour parameters varied significantly between MGs in both cultivars; L*, b* and Chroma decreased from MG1 to MG3 while a corresponding increase was found in a*, Hue angle and CIRG index. In ‘Opal’, Durofel^® values correlated hardly with any of the quality attributes within each MG, but better in ‘Victoria’; more in MG1 and MG2 than in MG3. In ‘Opal’, PNR10^® values correlated with most of the colour parameters within MG1 and MG2, but not MG3, in ‘Victoria’ similarly best in MG2. Sensory firmness evaluation discriminated between the three MGs. The two penetrometers tested discriminated between fruit firmness in three maturity groups. However; instrumental colour measurements did not always correlate well with penetrometer measurements. Further, it was revealed that it was difficult to grade plums with this type of colour development during ripening into three maturity groups by sensory evaluation of a combination of firmness and colour; the results indicated that grading the fruit into two groups only would likely give more reliable results.

Venche Talgø, Peder Lombnæs, Arne Stensvand (Norway) Greenhouse Study and Field Observations of Nutrient Disorders in Nordmann Fir (Abies nordmanniana)Christmas Treesin Norway (pp 98-103)

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Original Research Paper: Current season needle necrosis (CSNN) is a needle disorder on fir (Abies spp.) that has been associated with low calcium (Ca) foliage concentration in the USA. Shortly after bud break, randomly distributed needles form chlorotic spots that turn necrotic during the growth season. Another major needle disorder on fir is discoloured needle tips on two-year-old needles caused by Mg deficiency. The latter disorder is much more uniform than the former, i.e. all two-year old needles show symptoms. CSNN on the other hand, result in a mixture of healthy and diseased needles. Thus, the effects of low and sufficient supply of both Ca and Mg on plant mineral status were investigated on Nordmann fir (A. nordmanniana) grown in chelator-buffered nutrient solution in a greenhouse trial. Ca deficiency induced general chlorosis on new shoots, but no CSNN or Mg deficiency symptoms were obtained by suboptimal Ca and Mg supply. In field studies, no links were found between CSNN symptoms and Ca nutritional status.