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Composition of tomatoes and tomato products in antioxidants (WG1) page 42
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cultivars naturally presenting a somewhat poor foliage as well as the use of moderate nitrogen
rates to avoid excess of vegetative growth.
6.2.4. Influence of cultural techniques
6.2.4.1. Variety
Hamner et al.(1945) estimated that variations of tomato fruit vitamin C content due to
variety were small in comparison with variations caused by growing conditions.
Abushita et al.(1997) analysed tomato fruit from various poorly known cultivars
cultivated in Hungary and found variations on about 1 to 2-fold : from 250 to 480 mg/kg fresh
matter.
No data seem presently available for varieties currently cultivated in the European
Community. Genetic improvement might be possible as the wild spieces Lycopersicon
peruvianum reaches a fruit vitamin C content of 1190 mg/kg fresh matter.
6.2.4.2. Water
In tomatoes (var. Pusa Ruby) obtained from field experiments in winter and summer
on a sandy loam medium fertility soil, Dastane et al.(1963) observed that fruit vitamin C
content was increased by soil moisture depletion (40% and 50%) from 21 to 25.5 mg/100ml
of juice mainly in winter. Rudich et al.(1977) confirmed that low water tensions maintained in
soil by daily drip irrigation during the period of fruit development decreased fruit vitamin C
concentration together with soluble solids content while yield increased. Sanchez Conde
(1984) grew two cultivars of tomato (Marglobe and Moneymaker) in nutrient solution at three
levels of osmotic pressure (0.65 -normal-, 3.5 and 5.0 atmospheres) obtained by increasing
NaCl concentration. Fruit pulp vitamin C content decreased (231, 225 and 195 mg/kg fresh
matter for Marglobe and 196, 181 and 154 mg/kg fresh matter for Moneymaker respectively)
when osmotic pressure increased. But the total solids contents increased simultaneously (5.5,
9.5 and 9.6% for Marglobe; 5.4, 6.5 and 7.8% for Moneymaker respectively). An opposite
trend was reported by Albu-Yaron et al.(1993): in tomatoes (cv. VF M82-1-8) grown in an
aerohydroponic system in a greenhouse, the vitamin C levels were slightly positively affected
(variations between 8.5 and 12 mg/100ml juice) by the increase of the osmotic potential