Variedades crioulas de tomateiro: resgate, caracterização e cultivo em sistema de produção de baixo impacto ambiental com o uso de substratos à base de casca de arroz

Abstract

The rescue efforts with farmers, understanding plant behavior, and the implementation of specific phytotechnical management techniques for landraces are crucial aspects for the sustainable cultivation of tomatoes by family farmers. In this context, this dissertation focuses on documenting the rescue, multiplication, and selection of landraces tomato varieties preserved on-farm by family farmers, a seven-year endeavor in the central-southern region of the state of Rio Grande do Sul. The second theme explored involves evaluating the morphological, phenological, post-harvest, growth, and yield characteristics of these varieties. The research aims to highlight the main features of the six studied varieties due to the importance of preserving these varieties for traditional communities and family agriculture. Experiments were conducted over two crops, in the winter/spring/summer of 2022/2023 and the summer/autumn/winter of 2023. Variables analyzed included characterization through morphological descriptors, phenological evaluations recorded by dates and duration of two main phenological phases, subdivided according to their stages. Precocity and harvest duration were assessed in terms of periods, duration in days, and accumulated thermal sum. Fruit quality evaluations included the analysis of basic composition and phytochemicals. Biometric variables assessed were: number and weight of commercial fruits, fresh and dry mass accumulated from all plant organs, number of leaves, leaf area index, and harvest index. Results are organized into three articles. In the first article, a significant number of varieties preserved by guardians and social organizations were observed, emphasizing the importance of these social actors for agrobiodiversity conservation. Mini tomatoes stood out for their high productive potential, suggesting further studies to enhance income generation for social actors. The second article indicates diverse morphological characteristics among varieties, with Garrafinha being the earliest in fruit harvest during the 2022/2023 experiment. Vermelhinho, Perinha Amarelo, and Perinha Vermelho exhibited similar precocity. Although all varieties showed low levels of basic composition and phytochemicals, total acidity, L-ascorbic acid, and total carotenoids exhibited moderate elevation and reduced antioxidant activity. In the third article, results demonstrate that parboiled rice husk did not increase water retention capacity compared to "in natura" rice husk at the beginning of cultivation. However, there was an increase in water retention capacity towards the end. The addition of organic compost to parboiled rice husk showed the highest increase compared to "in natura" rice husk. Regarding substrate effects, they had a limited impact on plant growth in both experiments, as they did not promote differences in the production and distribution of dry mass among plant organs. With the addition of organic compost, substrates showed the best responses to the production variable, followed by "in natura" rice husk and parboiled rice husk. Concerning the effects of varieties ongrowth and production, Garrafinha exhibited faster apical growth, resulting in lower dry mass production of the stem. On the other hand, Grape Crioulo and Biofeliciana demonstrated a superior leaf area index, reflecting in higher dry mass production. Biofeliciana stood out in terms of production, being a variety with significant productive potential. Vermelhinho excelled in efficiently distributing assimilates to fruits, resulting in significantly higher production. However, despite positive results in average fruit weight, overall variety production was considered low for the cultivation system used, suggesting the need for adjustments and improvements to optimize production.