สมรรถนะการรวมตัวของลักษณะผลผลิต คุณภาพผล และการสะสมสารแคโรทีนอยด์ของมะเขือเทศเชอร์รี

Abstract

Currently, the popularity of cherry tomatoes is increasing around the world, including in Thailand. Most of the cherry tomato varieties used by farmers for commercial production are F1 hybrids. The selection of parental lines to produce superior hybrids is an important step in hybrid cherry tomato breeding. Therefore, this research aimed to evaluate the combining ability of yield, fruit quality and carotenoid accumulation characteristics of cherry tomato. The experiment was divided into three sub experiments, the first experiment was aimed to select cherry tomato parental lines for producing F1 hybrid. Fourteen inbred lines (101 - 109, 111, 201, 202, 204 and 205) and three commercial cultivars (Com. 1, Com. 2 and Com. 3) were grown under a plastic-net house and open-field in the dry season from October 2019 to February 2020. The result of the combined analyses showed that significant differences among genotypes and among environments, and significant genotype-by-environment interactions were found for all traits studied. A large proportion of variation for all traits was attributed to genotypes resulting good condition for selecting parental lines. The varieties 102, 103, 104 and 108 gave a high yield per plant (ranged between 1,700 - 2,000 g) and contained medium total soluble solids content (varied between 8.6 - 10.5%). High total soluble solids content (ranged between 10.3 – 11.5 %) was obtained in 101, 111, 201 and 202 variety. In addition, the varieties 101, 102, 103, 104, 108, 111, 201 and 202 had good carotenoid accumulation and also showed the variation in plant growth habits, fruit shape, size and color. Therefore, eight cherry tomato varieties were considered as potential parental lines for producing cherry tomato F1 hybrids. The second experiment was aimed to study the suitable environment for cherry tomato production in greenhouses. Three F1 hybrids, three varieties of male parents (102, 103 and 104), and two varieties of female parents (201 and 202) were grown under a plastic-net house and evaporative cooling greenhouse in the dry season from November 2020 to March 2021. The results showed significant differences among varieties, environments, and variety-by-environment interactions for all characteristics studied except variety-by-environment interactions for total soluble solid content trait. This study also found that the plastic-net house had high air temperature and low relative humidity. While an evaporative cooling greenhouse had a suitable level of temperature and relative humidity. As a result, fruit weight and fresh yield of cherry tomatoes grown under an evaporative cooling greenhouse (12.20 g and 704.0 g, respectively) were higher than those grown under the plastic-net house (10.33 g and 642.0 g, respectively). On the other hand, cherry tomato fruit under plastic-net house conditions contains more total soluble solid content (10.8%) than that under evaporative cooling greenhouse (8.9%). F1 hybrid from 201×102, 201×102, 202×103 and 202×104 had higher fruit yield than their male parents and contain more total soluble solid content than their female parents. Therefore, the cherry tomato hybrids production under an evaporative cooling greenhouse is suitable for producing good quality and high-yielding tomatoes. The third experiment, a half-diallel cross study of eight inbred lines 101, 102, 103, 104, 108, 111, 201 and 202 of cherry tomato was carried out with parents and F1 progeny, to determine the combining ability of yield, fruit quality and carotenoid accumulation characteristics under a plastic-net house and evaporative cooling greenhouse in the dry season from October 2021 to February 2022. The specific combining ability (SCA) variance component was significant for all traits, while general combining ability (GCA) was significant except for fruit number per inflorescence and fruit number per plant in an evaporative cooling greenhouse. The magnitude of SCA variance was more pronounced than GCA variance for all characteristics studied. The parental lines 101, 104, 111, 201 and 202 showed a high GCA values for yield and yield components. The parental lines 201 and 202 showed a high GCA values for total soluble solid content. While the parental lines 101, 102, 108 and 111 showed a high GCA values for phytochemical accumulations. Therefore, the most suitable parental line could be selected for developing high-potential hybrids for each trait. F1 hybrids from 104×101, 111×101 and 111×108 had an average of yield, yield components and total soluble solids content were higher than the commercial variety in both environments. Moreover, these hybrids also showed a high positive value of SCA, MP and BP for yield per plant and total soluble solids content. Therefore, F1 hybrids from 10×101, 111×101 and 111×108 are likely to be developed into commercial hybrid cherry tomatoes in the future.