Legume Genomics and Genetics 2025, Vol.16, No.3, 100-107 http://cropscipublisher.com/index.php/lgg 101 2 Diversity of Legume Germplasm Resources 2.1 Geographic distribution and species diversity in legumes Leguminous plants are distributed all over the world. Their diversity is mainly concentrated in East Asia, the Near East, Africa and the Americas. There are more than 800 genera and more than 20 000 species of legumes recorded so far, making it the third largest flowering plant family in the world. They are also a very important type of plant in global food production (Smýkal et al., 2015). For example, wild soybeans (Glycine soja) are mainly distributed in East Asia, especially the Korean Peninsula, where wild resources are very rich and are also important for the domestication process of soybeans. For example, white lupins (Lupinus albus) and beans (Phaseolus vulgaris) have adapted to a variety of climates and soil conditions. Their germplasm resources are spread across multiple continents and show rich genetic and trait differences (Tanwar et al., 2024). 2.2 Wild relatives and landraces as reservoirs of rare alleles Wild relatives and local varieties preserve many valuable genes. These genes are often lost during crop domestication, but they are useful for breeding, helping to increase yields, and improving adaptability such as disease and pest resistance and drought and salt resistance (Nawaz et al., 2020). For example, wild soybeans and wild peas (such as P. fulvum and P. sativum subsp. elatius) retain more genetic variation than cultivated varieties. These variations can provide some unique genetic resources for breeding programs (Smýkal et al., 2017). The same is true for local varieties. After long-term selection and adaptation by farmers, varieties in different places have different characteristics. For example, common beans in Portugal and the Himalayas contain many new genetic combinations, including some hybrids and hybrids (Jan et al., 2021). 2.3 Agro-morphological variation among accessions Leguminous germplasm resources differ in many agronomic traits. These differences are critical for selecting good varieties. Studies have found that crops such as beans, rice beans, adzuki beans, and cowpeas (Vigna stipulacea) show wide variation in growth patterns, leaf shape, flower color, pod and seed appearance, and nutritional content (Gore et al., 2022; Divakara et al., 2024). For example, beans from the Himalayas and Portugal vary greatly in seed size, shape, and nutritional content. Rice beans and adzuki beans from Asia also vary in flowering time, number of pods, and yield. If these trait data are analyzed together with molecular markers, useful materials can be found more quickly. This not only allows targeted breeding, but also establishes a core germplasm bank with strong representativeness and genetic diversity (Leitão et al., 2017). 3 High-Yield Related Traits in Legumes 3.1 Major yield components: pods per plant, seed size, biomass The yield of legumes is mainly related to several aspects, such as the number of pods per plant, the size of the seeds, and the biomass of the whole plant. Taking mung beans and broad beans as examples, studies have found that the number of effective pods per plant, the total number of seeds, and the weight of each seed will directly affect the final yield. Moreover, there are obvious differences in these traits between different varieties, which is a genetic difference. Some studies have also used meta-QTL analysis to find gene regions related to yield. These regions can affect traits such as the number of pods and seed weight. This kind of information is particularly useful for breeding work and can help breed new varieties with higher yields (Arriagada et al., 2022). In addition to these, researchers often use biomass and total seed production to judge whether the variety is good or not. Different varieties perform differently in different environments. Some varieties can grow more plants and seeds, while others are less so (Papastylianou et al., 2021). 3.2 Stress-resilient traits linked to yield stability The stress resistance of leguminous plants, such as drought resistance and heat resistance, is very important for maintaining stable yields. There are several physiological indicators related to these abilities, such as high chlorophyll content, strong leaf cooling ability, and good cell membrane stability, which are all related to high yields under harsh conditions (Sofi et al., 2021; Jha et al., 2025). For example, in drought resistance research, the "stress resistance index" is often used to measure, that is, to consider the yield performance of crops under normal
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