Maize Genomics and Genetics 2025, Vol.16, No.1, 45-59 http://cropscipublisher.com/index.php/mgg 46 advanced now, the potential of many traditional corn varieties has not yet been fully explored. We will focus on analyzing the genetic variation of different corn populations, especially those key genotypes that may be helpful for breeding. Of course, it is not enough to just find good genes. We also have to consider how to stably pass on these excellent traits. Especially in the context of climate change, maintaining corn diversity may become the key to improving yield and stress resistance. In the final analysis, this study is to provide breeders with some new ideas to make those good traits hidden in corn genes really work. After all, to feed a growing population, it may not be enough to rely on just a few high-yield varieties. 2 Fresh-Eating Maize Germplasm 2.1 Types of fresh-eating maize Speaking of fresh corn, you may not know that it is actually divided into several types. The most common is sweet corn, which tastes particularly sweet and tender, and many people like it. But it is not as simple as eating it fresh - most of the canned corn and frozen corn kernels in the supermarket are actually processed from sweet corn (Ruanjaichon et al., 2022; Dang et al., 2023). There is another type that you may have seen in hot pot restaurants, which is the kind of sticky glutinous corn. It is different from sweet corn, has a high starch content, and is sticky after cooking. Although it is very common in China and Southeast Asia, it is rare in the European and American markets (Ruanjaichon et al., 2022; Dang et al., 2023). Interestingly, although these two types of corn are both fresh corn, their uses and eating methods are quite different. There are some interesting new varieties of corn on the market now, which retain the sweetness of sweet corn and have the sticky taste of sticky corn. Breeding experts do not crossbreed randomly, they focus on key characteristics such as sweetness and stickiness to improve (Ruanjaichon et al., 2022). However, it is easier said than done. To breed such varieties, you must first figure out which genes control these characteristics. Researchers now use some molecular markers, just like marking genes, so that they can find the desired traits faster (Ruanjaichon et al., 2022). Although the process is quite complicated, the result does make corn more delicious. 2.2 Geographic distribution and diversity of fresh-eating maize germplasm Corn grown around the world is actually very different, just like people in different places have different tastes. North America is particularly fond of sweet corn, which has been grown for hundreds of years and now has countless varieties. Breeding experts have cultivated various inbred lines and hybrids, some of which have high yields and some are more disease-resistant (Hansey et al., 2012; Romay et al., 2013). Turning to Asia, the situation is different. Chinese and Southeast Asians prefer sticky corn, which is particularly popular there. Interestingly, although the planting area is not that wide, the varieties in each place are very distinctive, and they are slowly improved according to the local climate and eating habits (Ruanjaichon et al., 2022; Dang et al., 2023). You see, the same corn has developed completely different appearances in different places. Corn in Africa is very interesting, especially in the Sahel and coastal areas of West Africa, where you can see all kinds of local varieties in all shapes and sizes. These native corns are not simple, they have a very rich genetic diversity, which is a treasure trove for breeding improved varieties that are resistant to drought and disease. Speaking of diversity, corn in the northeastern Himalayas of India is no less diverse. There are so many local varieties there that it is dizzying that the corn in each field may be slightly different. Breeding experts attach great importance to these resources, not only because they can be used to improve varieties, but more importantly, to protect these precious genetic resources. After all, who knows if the climate changes one day and the special genes of these local varieties will come in handy? 2.3 Conservation and utilization status of germplasm resources When it comes to corn for fresh consumption, you may not know how important it is to preserve these varieties. Now countries are building germplasm banks to collect various corn seeds. The United States has done something interesting. They have conducted genetic testing on thousands of corn inbred lines (Romay et al., 2013). These data are particularly useful for breeders. Through analysis, they can find some rare gene variants and figure out which genes control important characteristics (Romay et al., 2013). Although it sounds quite technical, to put it bluntly, it is to preserve the diversity of corn. After all, no one knows when an inconspicuous local variety will help us cope with climate change or new pests and diseases.
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