Plant Gene and Trait 2025, Vol.16, No.1, 1-14 http://genbreedpublisher.com/index.php/pgt 5 will occur over time. Factors such as natural mutations, cross-pollination, and artificial breeding will gradually introduce new traits. Ismail et al. (2020) used SSR molecular marker technology to analyze 65 pineapple types, revealing two major genetic groups, proving that even cultivated pineapples can maintain a high level of genetic diversity during the planting process, providing a scientific basis for future variety improvement and genetic resource management. 3.2 Molecular markers and phylogenetic relationships Modern molecular marker technologies, like SSR, SNP and AFLP, provide powerful tools for distinguishing different types of pineapples. In the past, scientists mainly relied on external morphological characteristics, such as the shape, size or color of the fruit, to determine the differences between varieties, but now they can be analyzed directly at the DNA level. For example, SNP (single nucleotide polymorphism) markers can identify repeated fragments in DNA, thereby revealing the genetic relationship between different pineapple types. Some studies have even pointed out that today’s cultivated pineapples may be derived from multiple wild pineapple species rather than a single ancestor (Zhou et al., 2015). AFLP (amplified fragment length polymorphism) markers are also often used to cluster pineapple types, and the resulting groups often coincide with familiar cultivar groups, such as Cayenne and Queen (Rattanathawornkiti et al., 2016). AFLP technology has the ability to construct genetic “fingerprints”, so it is widely used in variety identification, germplasm resource protection and breeding material identification. 3.3 Key germplasm groups and their characteristics Pineapple germplasm resources mainly include commercially cultivated types, traditional local varieties (landraces) and wild species. At present, most of the pineapples grown in the global market are concentrated in a few varieties, mainly Smooth Cayenne and MD-2. These varieties are favored because they have high yields, moderate fruit size, strong transport adaptability, and are suitable for international export. However, as mentioned earlier, over-reliance on a few varieties also brings obvious disadvantages: reduced genetic diversity makes crops more vulnerable to pests and diseases (Zhao and Qin, 2018). In contrast, traditional local varieties and wild species have richer genetic variation. These old varieties have stronger ability to adapt to adversity and have unique flavor characteristics. Varieties like Queen perform well in arid areas of Africa and are suitable for dry and hot climates; while Red Spanish, which originates from Central America, is known for its strong insect resistance. Wild species also have extremely high breeding potential. For example, Ananas bracteatus performs well in disease resistance (Chen et al., 2019b), and A. macrodontes is drought-resistant, salt-tolerant, and has strong adaptability. It provides an important genetic basis for improving the stress resistance and quality of existing commercial varieties, and is a key support for future breeding and improvement work. In the modern breeding process, multiple molecular markers are used to conduct in-depth research on the genetic structure of these populations, and it is found that there are abundant genetic variations within these varieties. The Cayenne population has specific morphological characteristics and is classified as an independent cluster in phylogenetic analysis (Rattanathawornkiti et al., 2016). Hybrid breeding, gene introduction, and gene editing of these germplasm resources can improve the stress resistance of varieties, improve fruit quality, and enhance their adaptability to climate change. 4 Modern Pineapple Cultivars and Their Genetic Basis 4.1 Commercially important pineapple cultivars The global pineapple industry mainly relies on several highly commercialized varieties, which are superior in fruit quality, storage resistance and processing adaptability. Among them, Smooth Cayenne was once the most widely planted variety. Its juicy flesh, sweet and sour balance, and low fiber content make it the main choice for canning and export trade. However, this variety is sensitive to a variety of diseases (such as pineapple wilt), which limits its further promotion.
RkJQdWJsaXNoZXIy MjQ4ODYzNA==