Biodiversity in Tomatoes: Is It Reflected in Nutrient Density and Nutritional Yields Under Organic Outdoor Production?

Abstract

In many regions of the world, human nutrition is still characterized by an insufficient intake of essential nutrients like minerals such as iron (Fe) and zinc (Zn). In view of decreasing resources and a growing world population, the efficiency and the sustainability of cultivation systems should be considered not only in terms of crop yield and profit margin but also in terms of the yield of essential nutrients. Tomatoes are the most consumed vegetable in the world. Organic outdoor tomato cultivation is generally characterized by a higher diversity of varieties and lower fertilization input compared to conventional production. A 2-year field experiment with a set of 20 cultivars was performed to evaluate their variation regarding fruit mineral concentrations [potassium (K), calcium (Ca), magnesium (Mg), phosphorous (P), Fe, and Zn], their contribution to the dietary reference intake (DRI), and the nutritional yields (adults ha–1 year–1). Results show that mineral concentrations differed significantly by cultivar and by year. However, even though significant genotype-by-year effects appear, several cultivars exhibit high genotype stability across years for the single traits studied. Taking this together with medium-to-high heritability, genetics strongly controls most studied traits. Among the cultivars, the contribution of 100 g fresh fruits varied from 4.5 to 7.7% for K, 0.8 to 1.8% for Ca, 2.3 to 4.4% for Mg, 3 to 6.6% for P, 3.1 to 6.9% for Fe, and 1.9 to 4.2% for Zn to meet daily requirements. Based on average fruit yields per hectare, the cultivars varied with regard to the nutritional yields for all the studied minerals, but most strongly for Fe (44–120 adults ha–1 year–1) and Zn (22–84 adults ha–1 year–1). In terms of contribution to the DRI and nutritional yield for Fe, the cocktail cultivar “Bartelly F1” produced the highest results, while for Zn the salad cultivar “Bocati F1” showed the highest values. Our results show that the targeted use of tomato biodiversity in organic outdoor production can be suitable to achieve high fruit yields as well as to produce high nutritional yields per unit area, thus contributing to more effective land use and improved food security. These findings also provide valuable insights for tomato breeders to improve the tomato fruit quality while maintaining yield.

Morphological, Leaf Nutrient, and Fruit Quality Characteristics of Diverse Tomato Cultivars under Organic Low-Input Management

“…The experiments were carried out at Reinshof Experimental Station, University of Goettingen, at 152 m above sea level on organic fields of Fluventic Eutrochrept soil [22] from May to October in 2015 and 2016. Temperature, relative humidity, and soil properties during the experiments were previously described in Erika et al [23]. Additionally, available nitrogen concentrations in the soil during the growing period are shown in Table S1 in Supplementary Materials.…”

“…Fruit samples were then milled with a Mixer Mill MM 400 (Retsch, Haan, Germany) to obtain a homogenous fine powder. The concentrations of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulphur (S) in leaf and fruit samples were analysed according to Erika et al [23]. The ground leaf samples were also used to determine nitrogen (N) and carbon (C) concentrations by dry combustion (Elementar, Langenselbold, Germany).…”

“…DM = dry matter; TSS = total soluble solid; TA = titratable acidity; TPC = total phenolic concentration; GAE = gallic acid equivalent; FW = fresh weight; CV = coefficient of variation; ns indicates a nonsignificant difference; *, ** and *** indicate a significance difference of each factor and interaction at p < 0.05 p < 0.01, and p < 0.001 respectively; HSD (0.05) = critical value for comparisons by Tukey's honestly significant difference (HSD) test at p < 0.05; # data taken from Erika et al[23]. The cultivars are ordered based on average fruit weight.…”

Breeding Potential of Some Exotic Tomato Lines: A Combined Study of Morphological Variability, Genetic Divergence, and Association of Traits

“…It belongs to the Solanaceae family with a chromosome number 2n = 2x = 24, and is native to South America [3]. Tomato fruit is highly rich in nutritional values with a well-balanced amount of β-carotene, ascorbic acid (AsA), phenolics, flavonoids, vitamin E, minerals, and fibers [4,5]. It is generally considered as a "Protective Food" as it is the main source of lycopene and other antioxidants in the human diet that reduces cancer incidence [6].…”

“…Breeders and scientists around the world created a wide range of morphologically diverse cultivars from the single species S. lycopersicum to modern tomato varieties. These varieties have a high variation in fruit weight and size, shape and color through intensive activities of breeding [5,9]. In Bangladesh we have nearly 35 inbreed tomato varieties developed by the Bangladesh Agricultural Research Institute (BARI) and the Bangladesh Institute of Nuclear Agriculture (BINA) [10].…”