International Journal of Horticulture, 2025, Vol.15, No.5, 218-233 http://hortherbpublisher.com/index.php/ijh 229 Figure 2 Three sugarcane varieties of different colors. Badila (a), ROC22 (b), and FN15 (c) are shown. The rind and pith are shown on the left and right, respectively (Adopted from Ni et al., 2021) Of course, there are also high-sugar green-skinned varieties and low-sugar purple-skinned varieties, which mainly depends on their respective breeding parents and breeding goals. Taking the yellow-skinned sugarcane (also known as bamboo sugarcane) in Guangdong and the black-skinned sugarcane in Guangxi as examples, the field refractive sugar content can reach more than 16-18°Bx during maturity, which is comparable. However, the internodes of yellow-skinned sugarcane are longer, the fibers are looser, and the sweet juice is easy to release when chewing, while the internodes of black-skinned sugarcane are slightly shorter and the fibers are tighter, so the sweetness is released slightly slower but the aftertaste is stronger. There is no essential difference in the sugar accumulation pathways of the two, but the difference in fiber structure leads to different subjective sweetness perception when tasting: the green-skinned yellow sugarcane is more crisp and tender, and the juice quickly overflows the tip of the tongue, and the initial sweetness is strong; the purple-skinned sugarcane has harder fibers and needs to be chewed a few more times before the juice overflows, but the sugar concentration is high and the aftertaste is sweet and lasting. In general, there is little difference in the intrinsic sugar content between purple-skinned and green-skinned fresh sugarcanes, and the difference in sweetness between varieties is more due to the difference in sugar metabolism efficiency in their respective genetic backgrounds. For example, it has been reported that by comparing a pair of purple-skinned and green-skinned closely related lines, they have differences in the expression levels of sucrose transporter and invertase genes, resulting in different soluble sugar accumulation rates in the stems (Yuan et al., 2022). Therefore, in breeding, the sweetness should not be judged by skin color, but the sugar accumulation capacity of the variety should be evaluated by actual measurement through metabolic and molecular marker methods. 6.2 Texture variation among tender, juicy, and coarse genotypes Fresh sugarcane can be further divided into tender and crisp type, juicy type and coarse fiber type according to texture. Tender and crisp varieties, such as Guangdong's Baiyuzhu sugarcane, are characterized by thin and easy-to-peel skin, crispy stems, soft fibers, and easy-to-break residues when chewed; juicy varieties, such as Guangxi's Guitang Xinyuan series, have slightly soft stems but a lot of juice, and a mouthful of sweet juice when bitten; coarse fiber varieties, such as some tall sugarcanes or dual-purpose sugarcanes, have thick stems but high fiber content, and the residues are not easy to break after chewing and need to be spit out. These texture differences first come from the differences in cell wall composition and structure. Tender and crisp sugarcanes often have low fiber and lignin content, thin cell walls, and underdeveloped mechanical tissues, so the stems are tender and easy to break. For example, experimental data show that the fiber content of some tender and crisp sugarcane varieties is only about 5% (fresh weight basis), which is significantly lower than the 8%-10% level of ordinary sugarcane (Chen et al., 2022), which confirms that low fiber content is conducive to improving the crisp
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