General introduction 9 1 high yield, and also a short life cycle, the economic value makes growing it attractive to breeders and farmers (Naika et al., 2005). Advancements in greenhouse technology enable year-round cultivation, making tomatoes an accessible crop regardless of season. The plant’s growth characteristics, such as its sprawling vine-like nature and support requirements, further contribute to its cultivation practices. 1.1.2 Tomato growth habit Tomato (Solanum lycopersicum) is a highly versatile plant that reaches impressive heights exceeding two meters. With careful maintenance, tomato plants can be harvested consecutively for multiple years, offering prolonged productivity. The first harvest typically occurs within a span of 45-55 days after flowering (Naika et al., 2005). In our experimental set-up, tomatoes flower at 35-42 days. Among the diverse tomato cultivars, two main categories can be distinguished: cultivars for fresh consumption and cultivars for processing. We selected a cultivar from each category as our experimental models, Moneymaker (MM) and M82, respectively. Moneymaker stands out as an exceptional greenhouse variety renowned for its abundant yield, delightful bright red fruits, and smooth texture, making it an ideal choice for fresh consumption. This particular cultivar thrives in hot and humid climates, demonstrating its adaptability both outdoors and within greenhouse environments. MM, while not a current choice for large-scale greenhouse farming due to the availability of more modern varieties in recent years, it still remains a greenhouse variety favored by home gardeners. Originating from England, Moneymaker exhibits vigorous vine growth, necessitating proper staking to optimize results (Marks, 2010). M82 is a processing tomato, suited for field growth and machine harvest. M82 plants typically reach a height of 1.5 to 2 meters and have a bushy growth habit. The fruits are typically red when fully ripe, with a smooth skin and a juicy, flavorful flesh but comparing to MM, the fruits are less oval. In our greenhouse set-up, we noticed M82 and Moneymaker (MM) have very similar life cycle and flowering time within 5-6 weeks, similar height with around 1.5 m. To distinguish these two species (Figure 1.1), we can use the first true leaf. The first true leaf of M82 and MM has a distinguishable pattern as shown in Figure 1.2. M82 usually has smaller main leaf lamina more similar to a simple leaf, whereas MM has a leaf pattern more similar to later true leaves with clear separation of each leaflet.
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