Plant Gene and Trait 2025, Vol.16, No.1, 1-14 http://genbreedpublisher.com/index.php/pgt 7 resistance. For example, the EU-funded pineapple germplasm project studied the genetic structure of Ananas and Pseudananas and applied resistance screening technology to enhance the disease resistance of pineapples (Carlier et al., 2012). Molecular characterization techniques (such as restriction fragment length polymorphism (RFLP) and PCR-RFLP) facilitate the identification of genetic markers, thereby more accurately selecting target traits during hybridization. With better tools now available, like marker-assisted selection (MAS) and genomic selection (GS), it’s easier to find and select the traits breeders want. These methods save time and improve accuracy. In fact, similar approaches have worked well in other crops. For example, Bertioli et al. (2021) used wild species in peanut breeding to develop varieties that could resist disease- an effort that’s helped boost food security. 5.2 Contributions of wild relatives to breeding Wild relatives of cultivated crops are an important source of genetic diversity, providing excellent traits such as disease resistance, improved fruit quality and environmental adaptability. In pineapple breeding, Ananas bracteatus showed strong resistance to pineapple wilt (Fusariosis), while Ananas macrodontes had strong drought tolerance and salt tolerance (Qiao et al., 2021; Feng et al., 2022), and these traits can be used to improve the adaptability of modern pineapple cultivars. Genomic tools have made this work much easier. With methods like marker discovery and trait mapping, breeders can find useful genes in wild plants and track them as they’re added to commercial types. But for this to work well, the wild germplasm needs to be carefully studied and clearly recorded. As Migicovsky and Myles (2017) noted, having good genomic data on wild species is especially important for perennial crops like pineapple. 5.3 Challenges and opportunities in germplasm utilization The sharing of germplasm resources has long been promoting the production and improvement of excellent pineapple varieties. However, there are still some practical obstacles, the most prominent of which is the legal level. Regulations on biodiversity and genetic resources are becoming increasingly stringent around the world. As more countries strengthen the management of the entry and exit of germplasm resources, the cross-border flow of seeds and plant materials has become increasingly difficult. This directly affects the ability of breeders to obtain the required genetic diversity and slows down the development of new pineapple varieties (Bertioli et al., 2021). In terms of resource protection, technologies such as in vitro preservation and cryopreservation are being widely used to preserve rare or precious germplasm resources to ensure that these genetic materials can still be used in future breeding work. Global cooperation is also becoming increasingly stronger. Institutions such as the International Plant Genetic Resources Institute (IPGRI) and the Food and Agriculture Organization of the United Nations (FAO) are promoting the establishment of global germplasm banks and encouraging the sharing of knowledge and germplasm materials (Shaw et al., 2023). 6 Impact of Germplasm Flow on Stress Tolerance 6.1 Genetic resources for abiotic stress tolerance Some pineapple varieties from arid regions of South America and Africa have shown outstanding drought resistance (Lin and Ming, 2018). Among them, Ananas macrodontes is a typical example. It can grow deeper roots to obtain water from dry soil and survive well during long droughts (Zhao and Qin, 2018). At the same time, in Southeast Asia and some coastal areas of Africa, soil salinization is becoming an increasingly serious problem, which has become an important factor restricting pineapple cultivation. Studies have found that A. bracteatus has strong salt tolerance and its leaf epidermis is thicker, which helps to reduce water evaporation and can still maintain healthy growth in saline soils (Chen et al., 2019b). The Queen variety, which is widely grown in Southeast Asia, is resistant to high temperatures, while some traditional local varieties in South America also show moderate cold resistance. At the molecular level, scientists are gradually revealing the genetic mechanisms of pineapple's response to drought and salt stress. Whole-genome studies have shown that the AcoCPK gene family plays an important role in regulating plant stress responses (Zhang et al., 2020). These genes have evolved over a long period of time to enhance the survival of pineapples under different climatic conditions. Interestingly, some studies have found that
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