Grégoire Bianchetti is a biology student at the University of Angers. He chose Dahari for his end-of-year internship. Its main mission: to set up a varietal screening experiment, to identify the varieties best suited to the needs of producers.
Tomatoes, the first market garden production in the Comoros
On the island of Anjouan, tomatoes are grown all year round. The harvest takes place two to three months after planting, which makes it an easy market garden to implement in addition to food crops. The period when we find the most tomatoes on the market is from May to August. It sells for 200 to 500 francs per kilo. In the dry season, it is less cultivated and therefore more expensive. Its price can rise to more than 1000 francs per kilo.
Tomato crops are threatened mainly by flies, slugs, viruses and bacteria. Anjouan producers mainly plant tomatoes of the Mongal varieties for low altitude plots and Floradae for those at high altitude. The experiment carried out by Grégoire during his internship aims to test four new varieties of tomatoes, to compare their resistance to various threats and their adaptation to the Anjouan climate.
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The varietal screening experience
The experiment was set up by Dahari, following a recommendation from CIRAD. The experiment was carried out on a plot of the regional economic development center (CRDE) of Salamani. Three people worked on the technical realization of the varietal screening: Grégoire, but also the site manager Inzou Ali and the CRDE worker Hachim Saïd Ali. On a 75m2 plot with high humidity and partial shade, they planted 200 tomato plants, of four different varieties: a local variety (Mongal) and three imported varieties (Kiara, Cobra, Rodéo). The tomato plants were planted the week of April 15, and evolved under the same conditions: an addition of manure before planting, and no pesticides or fertilizers. Data on their development was collected once a week until the week of June 8. The criteria followed during the experiment are: productivity, disease resistance, flavor (a posteriori taste test), and resistance to transport.
The results of the experiment
Among the four varieties tested during this varietal screening, Grégoire highlights the good development of the Cobra variety, which appeared over the weeks to be the most adapted to the conditions of the CRDE plot. It is this variety which has best resisted attacks from pests, which has had the most rapid development with vigorous, full and healthy plants.
Grégoire definitely advises against the use of the Rodéo variety for plots similar to that of the CRDE, at low altitude. The plants are not at all resistant to diseases and parasites, the flowers appear late and the plants are stunted. The Rodeo variety cannot develop properly at such altitudes.
Finally, the Mongal and Kiara varieties presented relatively similar development, growth and phytosanitary status throughout the experiment. Over the last weeks of the test, the Mongal variety very slightly outperformed the Kiara variety.
Summary table of the results of the experiment at the end of the 5th week
Grégoire's recommendations12
“It is relatively early to respond to the initial problem which was to recommend a variety to producers among the four varieties tested. At the end of my internship, I was not able to test the firmness and taste of the fruits, because some varieties had still not produced fruit.
So, if a producer asked me about the choice to make among these four varieties for a low altitude plot, I would certainly advise him not to use the Rodéo variety. I will then suggest that he cultivate the majority of his plot with Mongal plants, already proven in the Comoros, in order to ensure tomato production.
Finally, on a small plot initially, I will suggest cultivating the Cobra variety which seems promising. »
