International Journal of Horticulture, 2024, Vol.14, No.4, 263-274 http://hortherbpublisher.com/index.php/ijh 266 The genetic distances between carrot varieties, such as the high genetic distance between Purple Dragon and other varieties, underscore the extensive genetic diversity present in the carrot gene pool (Domblides and Domblides, 2023). This diversity is an important resource for developing high-yield and disease-resistant carrot varieties in breeding programs. 3 Developing High-Yield Carrot Varieties 3.1 Identifying yield-related markers The development of high-yield carrot varieties is a key focus in carrot breeding research, aimed at increasing crop yields through genetic improvement to meet the growing market demand. In this process, marker-assisted selection (MAS) technology is widely used to identify genetic markers associated with high yield, thereby accelerating the development of superior varieties. Identifying yield-related genetic markers is a foundational step in achieving this goal, as modern molecular breeding techniques can precisely locate gene regions closely related to high-yield traits. In recent years, Amplified Fragment Length Polymorphism (AFLP) marker technology, known for its high polymorphism and genome-wide coverage, has been extensively applied in carrot breeding. This technology not only evaluates the genetic diversity among carrot genotypes but also reveals potential markers related to high yield. For instance, AFLP analysis has been successfully used to differentiate various carrot genotypes, uncovering significant genetic differences, which is crucial for selecting varieties with high-yield potential through MAS technology (Domblides and Domblides, 2023). The application of this analytical method provides valuable genetic information for carrot breeding, assisting breeders in the early selection of varieties with excellent agronomic traits. Moreover, Simple Sequence Repeat (SSR) marker technology has also shown great potential in high-yield carrot breeding and plays a critical role within the MAS framework. SSRs, due to their high polymorphism, even distribution, and ease of use, have become a powerful tool for assessing the genetic diversity of carrot parental lines. In carrot breeding, SSR markers can effectively evaluate the genetic differences between parental lines, identifying those genotypes with high-yield potential (Janani et al., 2023). Through SSR marker analysis, breeders can more accurately select parent lines under the support of marker-assisted selection, leading to the development of higher-yielding hybrids. Compared to traditional phenotypic selection, this marker-based selection method significantly improves breeding efficiency, not only shortening the breeding cycle but also increasing the likelihood of breeding success. 3.2 Breeding strategies for high yield Breeding strategies for high yield in carrots often involve the use of marker-assisted selection (MAS) and heterosis breeding. MAS allows for the precise selection of desirable traits at the genetic level, significantly enhancing the efficiency of breeding programs. For example, the use of MAS in other crops, such as rice and potatoes, has demonstrated its effectiveness in improving yield by incorporating multiple beneficial genes (Beketova et al., 2021; Mohapatra et al., 2021). Wani et al. (2018) highlighted the significant economic benefits of using molecular markers to track genes of interest in plant breeding. MAS technology enables the rapid and precise selection of stress-resistant traits, showing great potential particularly in areas such as environmental stress tolerance, disease resistance, mineral, and osmotic requirements. Gouda et al. (2020) explored the application of MAS in rice yield improvement, particularly focusing on the introduction of QTLs/genes related to grain number and yield. The study demonstrated that the introduction of multiple favorable QTLs through MAS could significantly enhance rice yield; however, the method may be limited in situations where resources are scarce and costs are high. MAS technology is widely applied in crop breeding, aiding in the rapid selection of individuals with desirable traits and thereby improving breeding efficiency. Through MAS, genes or QTLs related to yield can be effectively identified and introduced into target crops. This has potential applications in carrot breeding as well, where it can accelerate the development of superior hybrid varieties (Kumawat et al., 2020). In carrot research, hybrid vigor breeding, which involves crossing genetically diverse parents to produce hybrids with desirable traits, has proven
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