Tomato Flavor Affected by Variety and Production System

Heirloom tomatoes are in high demand because consumers expect them to have excellent flavor and they are available in many attractive colors and sizes. There is also a growing demand for organic heirloom tomatoes. Although this is a good opportunity for farmers, there are some problems associated with growing heirloom tomatoes, particularly organic ones. These include disease susceptibility, lack of research on effective organic production systems, and limited information on how varieties perform and are accepted by consumers. In order to address these problems, NC State University started a research program on heirloom tomatoes in 2005.  Over the past four years, that project has shown that an organic production system can be as effective and productive as a conventional one. Furthermore, some of the heirloom varieties and heirloom-type hybrids are very disease resistant and well suited for organic production in the Southeast USA. To understand the fruit biochemistry of different heirloom and heirloom-type hybrid tomato varieties in 2008 we compared flavor rated by sensory methods and fruit quality components such as organic acids, sugars and volatiles of tomato varieties grown under different production systems. The varieties were the heirloom-type hybrids, NC 118L, NC 161L, and Mountain Magic, and the heirloom varieties Mr. Stripey, Red Brandywine, and Stupice.  They were grown under four production systems- conventional, an organic system based on the fungicide Sporatec and the insecticide Ecotec, an organic system based on the fungicide Serenade and the insecticide Neem, and a control. In this study, ‘Mountain Magic’, ‘Stupice’, and ‘Red Brandywine’ were rated the best in consumer taste tests and also had the highest organic acid content. This indicates that organic acid analysis may be a fair criterion for screening genotypes for flavor. Interestingly, fruit from the two organic systems had the highest concentration of organic acids, which was positively correlated with flavor. This indicated that tomatoes grown under organic conditions may have better flavor than those grown under a conventional system. Total acid content and sugars were negatively correlated indicating that organic acid is converted into sugars when fruits are ripe. Across all varieties, there was no difference in total marketable yields among the conventional or organic production systems, but they were all higher than the control. Across all production systems, ‘Stupice’, ‘Mr. Stripey’, and ‘Mountain Magic’ had higher marketable yields compared to ‘Red Brandywine’ and ‘NC 118L’.