Maize Genomics and Genetics 2025, Vol.16, No.2, 60-69 http://cropscipublisher.com/index.php/mgg 65 Li, 2020). Although each technology has limitations when used alone, such as transcriptomics can only look at gene expression, and metabolomics mainly analyzes metabolites, but analyzing their data together can provide a more comprehensive understanding of the ins and outs of corn trait formation. Interestingly, this method can not only find key genes, but also discover important metabolic pathways. Of course, the amount of data in actual operation will be very large, but it does help breeders screen out excellent varieties more quickly. 6 Development and Commercial Applications of Fresh Corn Germplasm Resources 6.1 Commercialization of local varieties In the field of corn breeding, local germplasm resources have always been a treasure trove, although it is indeed difficult to use. Take tropical corn for example. On the surface, it does not match the temperate environment, but experiments have shown that they contain many good genes (Hallauer and Carena, 2014). Now more and more breeding projects are starting to target these local varieties, especially to meet the needs of specific regions. However, it is certainly not enough to rely on university research institutes alone. Thanks to those public-private partnership projects (Byerlee, 2020), old varieties and new technologies have been linked together. But the specific effect depends on the local water, soil and climate. It is not applicable to all places. 6.2 Promotion of ecotype fresh corn When it comes to corn variety improvement, more and more attention is paid to new varieties that adapt to specific environments. Although traditional varieties perform well under ideal conditions, they cannot withstand extreme weather such as drought and high temperatures. CIMMYT has done a lot of work in this regard (Prasanna et al., 2021). They use tropical corn germplasm with strong stress resistance and modern breeding technology to cultivate a batch of more adaptable varieties. Interestingly, these new varieties have indeed performed well after being promoted in rain-fed areas (Ortiz et al., 2010). They are not only resistant to diseases, but also have relatively stable yields. Of course, some adjustments may need to be made in different regions, but the path of eco-breeding has indeed helped farmers solve many practical problems. 6.3 Market-oriented resource development The market now has higher and higher requirements for fresh corn. It must not only taste good, but also look good and be easy to process. Although traditional breeding can also improve quality, progress is relatively slow. Interestingly, new methods such as double haploid technology have been used recently (Andorf et al., 2019). Through precise regulation of genomic information, the bred corn has significantly improved taste and processing performance. However, laboratory research alone is not enough. Involving farmers in improvement, as in the Chiapas region of Mexico (Bellon and Risopoulos, 2001), and adjusting according to local actual conditions will have better results. Of course, in specific operations, each place may have to explore a path that suits them. 7 Successful Cases of Fresh Corn Germplasm Development 7.1 Breeding of high-sugar varieties When it comes to sweet corn breeding, the original intention was to make corn sweeter. Researchers have found that by regulating the starch synthesis pathway, especially by introducing recessive genes such as sh2 (Revilla et al., 2021), corn can accumulate more sugar. Interestingly, by combining the mutant genes sh2, Pr1 and o2 (Jompuk et al., 2020), not only the sweetness is improved, but also the protein and anthocyanin content. Of course, there will be many problems in actual operation. For example, Saha et al. (2022) used backcrossing technology to successfully combine the two characteristics of high sugar and stress resistance (Figure 3). Most of the popular sweet corn varieties on the market now come from this, although the taste preferences of consumers in different regions may be different. 7.2 Commercialization of waxy corn Sticky corn is particularly popular in Asia, especially in China and Southeast Asia, where people often cook and eat it directly (Ruanjaichon et al., 2022). However, to make it taste better, breeders have come up with many ways. For example, hybridizing super sweet corn with sticky corn, so that the improved variety tastes more fragrant. Although traditional breeding methods are time-consuming, now with functional markers such as MassArray,
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