STRAWBERRY F1 HYBRIDS IN VERY EARLY
GREENHOUSE PRODUCTION WITH GROW LIGHT
G.C.M. Bentvelsena, D. Souillata
a
ABZ Seeds, Vleetweg 12, 1619PR Andijk, The Netherlands
ABSTRACT
The near saturation of the strawberry market in the main season in NW Europe is responsible for
a low price and so a loss for strawberry producers. In order to be able to sell strawberry with a
high price, the production should be starting more early in late winter. This can be realized by new
varieties and an adapted environment.
In an extended consumer test, executed by Wageningen University, Bleiswijk, ABZ F1 hybrids were compared with
well known and appreciated Dutch strawberry varieties, produced in a greenhouse with grow lights (Fig 3).
Fig. 3: Consumer test on WUR, Bleiswijk NL on 19 March 2013. Number of participants is 46.
This study was conducted to evaluate the performance of F1 hybrids in very early production from
mid February onwards in a greenhouse with grow light in the Netherlands.
Three new F1 hybrids from ABZ Seeds were tested in a greenhouse compartment at the Demotuin
(Honselersdijk, NL) during a very early culture in 2013. These new F1 hybrids are seed propagated
(disease free) and day neutral.
During the entire production season, climatical data, fruit yield and quality were recorded. Fruit
quality characteristics were measured, like fruit appearance (color, shape), firmness, storage
life and taste (tasting and measurement of sugars and acids). The quantity of fruits produced is
monitored also with a special attention to the production spread during the season.
1Introduction
The goal of this project is to show the possibilities of harvesting high quality strawberries starting in February. With
good flavored F1 hybrid strawberry varieties in a greenhouse with grow lights, North Western European growers
would have access to a high value market from begin February onwards.
Chemical composition of harvested fruit was measured at ABZ Breeding Station on 22nd March 2013. ABZ hybrids
were compared with one entry of imported strawberries from Spain (Table 1).
Table 1: Chemical analysis of strawberry fruit at ABZ Breeding Station Andijk, NL on 22 March 2013.
2 Material and Methods
Variety
brix
% average
sugars
% average
acids
% average
sugars/acids
% average
L 13
110
98
103
94
K 698
112
110
111
97
L9
103
102
108
93
Candonga SP
93
91
87
104
Unknown SP
75
85
72
117
2.1 Plant material
Three experimental F1 hybrids were chosen: K698, L9, L13. They are all ever-bearers specially developed for early
greenhouse production and seed propagated. Seeds were sown at ABZ Seeds Breeding Station at Andijk, NL on
14th September 2012. Plants were planted in a compartment with hanging gutter system at the Demonstration
Station, Honselersdijk, Westland area, on 28th December 2012. The facilities in the compartment consisted of grow
light (Son-T, 10.000 Lux), heating system, dripping system and CO2 distribution. Each hybrid is planted in two rows
of 60 plants. Plant density is the same for all entries, 5 plants per m2.
2.2 Methodology
4Discussion
Strawberries were harvested two times a week. Per entry, weight and number of fruits were noted. Spreading of the
production, total yield per plant and average fruit weight were recorded.
4.1 Culture and climate
Aspects of fruit quality were evaluated during the season. Brix was measured with 7 or 20 fruits per entry with a
digital refractometer. Detailed enzymatic analysis were done to determined sucrose, glucose, fructose, citrate and
malate contents. Samples from 7 fruits per entry were used, with 2 replications. Supermarket strawberries from
Spain (Candonga) were used as comparison. Total sugars, total acidity and an index sugars/acids were calculated.
Harvest started three weeks later than expected. This can be explained by the state of development of plants when
they were planted in December. The ideal stage would be with a first flower open; this was not the case. We expect
this can be achieved next year by a more early sowing. Climate regulation is also an important point to consider.
This will help to have a better spread and a continuous production.
4.2 Production potential in early season
Tasting sessions were also organized. For one part by Wageningen University at Bleiswijk, a session was realized
with a representative tasting panel. Strawberry varieties Sonata and Lambada from a Dutch greenhouse with
grow lights were used as comparison. For the other part, regularly tasting sessions were organized at ABZ Seeds
Breeding Station at Andijk.
At the end of the production period, total productivity was on an acceptable level of almost 8 kg/m2. This
production is on a satisfactory level of 2 kg/m2/4 weeks. First half of the period, week8 – week 16 needs further
improvement by better control of greenhouse climate. Another possibility to improve total production is to start
production more early in week 5.
3Results
4.3 Greenhouse strawberries with flavour
3.1 Strawberries production
In a period of 16 weeks, depending on F1 hybrid experimental, between 1.440 grams and 1.580 grams per plant
or 7,2 - 7,9 kg/m2 was harvested. (Fig 1).
Fig. 1: Spring trial at Demo Station, Honselersdijk, total strawberry production in grams per plant
The key to successful marketing of strawberries in very early season would be consumer acceptance. In a first
indicative taste trial we showed that greenhouse grown ABZ strawberries were far better appreciated by consumers
than field grown Spanish strawberries. In a second, extended taste trial ABZ strawberries from the Demo station
were compared with Dutch greenhouse grown strawberries. A significant difference was measured between two
of our varieties and the well known Dutch varieties Lambada and Sonata. ABZ F1 L13 turned out as the most
promising F1 hybrid with flavour.
The consumer test were confirmed by the chemical analysis of the fruit. Total chemical content and also content of
sugars and acids were considerable higher in fruit of ABZ hybrids, compared with Spanish grown fruit. The balance
between sugars and acids seem to be in favour of Spanish strawberries.
5Conclusions
This first growing trial in a greenhouse shows there is good potential in very early production of strawberries in
North West Europe. Flavor characteristics of ABZ hybrids are superior on imported strawberries in the same period
of the year. The comparison on flavor with Dutch short day varieties is in general also in favor of the ABZ gourmet
hybrids. On top of that, the aromatic fruit flavor of ABZ hybrids was confirmed by professionals in the gastronomic
market.
The plant quality and growing strategy in a greenhouse with grow light needs further improvement. Plant quality
can be further adapted to this growing concept by adjusting sowing date and growing circumstances in the nursery
greenhouse. The production pattern can be further improved by adjustments in climatic control of the greenhouse
and the right choice of container size, plant density and planting time.
Acknowledgements
We like to thank Demokwekerij Westland at Honselersdijk and Wageningen UR at Bleiswijk for their contributions to this project.
References
3.2 Strawberries analysis
During the early part of the season several panel tests were executed in order to find out consumer acceptance
of the fruit. On 27th February 2013 a small scale consumer test was executed at ABZ Breeding Station to find out
differences in consumer acceptance between ABZ varieties and a standard strawberry variety imported from Spain.
Difference in consumer acceptance between Dutch greenhouse strawberries and imported Spanish strawberries
was obvious (Fig. 2).
Fig. 2: Consumer test on ABZ Breeding Station Andijk, NL on 27 February 2013. Number of participants is 5.
Bentvelsen G. C. M., Bouw E., Veldhuyzen van Zanten J.E., 1996, Breeding strawberries (Fragaria ananassa Duch.) from seed,
Proceedings of the third international strawberry symposium, Acta Hort. 439:149-153.
Bentvelsen G.C.M., Bouw E., 2000, Breeding strawberry F1-hybrids for vitamin C and sugar content, Proceedings of the fourth
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