- François-Xavier Branthôme
The processing tomato is one of the sectors that most weighs on the economy and best represents the Italian made products in the world. Regardless of the growing environment, to obtain high processing yields and high quality industrial derivatives, the raw material must be of the best quality. For this purpose, a new research project was implemented.
The "Innovative agronomic techniques to increase the dry matter content and Brix grade in processing tomatoes" was launched by Italia Ortofrutta - Unione Nazionale, co-financed by its eleven Producers' Organizations under the scientific supervision of the research center CREA.
The aim of this research project is to increase the quality and profitability of industrial tomatoes in different Italian production areas.
"The quality, intended as the percentage in soluble and total solids of the tomato fruit, and measured by °Brix (sugar content) and dry matter, is influenced both by intrinsic factors of the plant (genotype) and by extrinsic factors (climate and cultivation technique). The analysis of this strong interaction is the key to increase the quality of the raw material destined to the transformation," said Mario Parisi, researcher at CREA OF in Pontecagnano (SA).
"The genetic structure of the hybrid is of fundamental importance. The last thirty years have seen intense efforts in the field of the plant breeding to improve the quality of the fruit. To date, the DNA traits that lead to higher values in terms of °Brix and dry matter are known and, thanks to the sequencing of the genome of the cultivated tomato, it is possible to obtain modern genotypes highly performing. Consequently, the varietal choice represents the first step to achieve excellent results. The environment, and even more the interaction between the latter and the plants, play an important role on the development of these traits. Thus, it is necessary to test, for each growing environment, new crossbreeds for the desired traits (soluble and total solids, in this case) in repeated experiments over several years, also to assess the year of cultivation," continued Parisi.
Which cultivation factors or which techniques can be used to improve the quality of the tomato? "We must certainly consider irrigation and fertilization as agronomic aspects that, if well managed, can increase the quality of the tomato," answered Mario Parisi.
"High water volumes facilitate yield production increases, but cause a deterioration in the quality of the berries as regards the refractometric index and dry matter. Recent studies show that it is possible to reduce irrigation volumes by up to 50% of the potential need, starting after the end of the flowering period, without compromising the productive potential of the plants and thus improving the quality of the berries. In this way, it also pursues a greater efficiency of water use and a more eco-sustainable management of the crop".
Nitrogen and potassic fertilization
"Nitrogen fertilization, as is well known, favors the growth and production of the plant. However, beyond the optimal dosage, which varies by genotype and the growing habitat, we find a reduction in the efficiency of the use of nitrogen and a tangible deterioration in quality. Numerous studies show that potassic fertilization favors the increase of dry matter, refractometric index, sugars and acidity. Several authors report that potassium improves the coloring of fruits, increasing the content of lycopene and reducing that of b-carotene".
"Recently, considerable importance has been attributed to foliar fertilization especially with fertilizers with high potassium content, applied when the berries start veraison (beginning of ripening). In addition, an improvement in fruit quality (°Brix and dry matter) today is also achievable through the use of complex foliar fertilizers containing oxylipins, phenylalanines and monosaccharides (protein hydrolysates and algae extracts) that stimulate the ripening process through an acceleration of the physiological activities of the plant and a reduction of organic acids present in the fruit".
The CREA OF (scientific responsible) and the CREA AA are evaluating the effect of different agronomic practices and innovative technical solutions to obtain high quality standards in the production of processing tomatoes in three areas of high specialization (Campania, Puglia and Emilia Romagna), as part of the applied research project (2019-2020) "Innovative agronomic techniques to raise the dry matter content and Brix grade in processing tomatoes" (Measure 4 - Research and experimental production - of the National Fruit and Vegetable Strategy 2018-2022 referred to N. 9194035 of 30/09/2020), mentioned above.
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Sources: freshplaza, tecnicheinnovativepomodoro.jimdofree