Sugarcane, a vital cash crop, contributes significantly to the world’s sugar supply and raw materials for biofuel production, playing a significant role in the global sugar industry. However, sustainable productivity is severely hampered by biotic and abiotic stressors. Genetic engineering has been used to transfer useful genes into sugarcane plants to improve desirable traits and has emerged as a basic and applied research method to maintain growth and productivity under different adverse environmental conditions. However, the use of transgenic approaches remains contentious and requires rigorous experimental methods to address biosafety challenges. Clustered regularly interspaced short palindromic repeat (CRISPR) mediated genome editing technology is growing rapidly and may revolutionize sugarcane production. This review aims to explore innovative genetic engineering techniques and their successful application in developing sugarcane cultivars with enhanced resistance to biotic and abiotic stresses to produce superior sugarcane cultivars.

The rebaudioside-A/stevioside (R/S) ratio influences the breeding and commercial values of stevia genotypes. Three stevia genotypes, “High Sugar,” “Levan,” and “ShouA3-2,” with respectively high, medium, and low steviol glycoside (SG) contents were investigated to answer the following questions: how do SG contents change when NaCl induces gene expression? Is SG-content positively correlated with NaCl tolerance? Does the genotype, with a high R/S ratio, exhibit higher expression of SG genes; compared to the genotype, with a low R/S ratio? Growth parameters, through our results, were decreased in “High Sugar” and “ShouA3-2” relative to “Levan” who showed better performance under the severe 200 mM NaCl treatment. Extendedly, “High Sugar” decreased the expression of SG-genes (cpps, ks, kh, and ugt74) under the low 50 NaCl treatments, while the “ShouA3-2” has upregulated all the genes (except ks) under the moderate (100 mM) NaCl treatments. Overall, the antioxidant sod1 gene was upregulated, similarly, the “Levan” has upregulated the cpps, while differentially expressed ks and kh across the NaCl treatments. In conclusion, high R/S ratio does not necessarily mean enhancement in responses to abiotic stresses in stevia. The R/S ratio in stevia does not solely rely on the expression of SG-pathway genes thus; other ancestral genetic elements may independently regulate them. Under salinity, the rooting characteristics improved when R/S ratio was low, while when moderate the shooting characteristics were superior. We recommend breeding for moderate R/S ratios to assure probable resilience to challenging climates (such as salinity) and potent higher agronomic traits.

In Egyptian sugarcane breeding program, a pot experiment was carried out during 2019 season at Agricultural Research Station, Giza Governorate (latitude 26o 33? N and longitude 31o 12? E), Egypt, to evaluate twenty sugarcane clones, compared with the cultivated variety GT.54-9, under three irrigation water levels IWL (100, 80 and 60% of IWL). The traits FW of the shoot and root, root: shoot ratio, LAI, LAR, Chla, Chlb, Chla: Chlb ratio, carotenoids and proline were assessed. From this study clones 17 had height shoot fresh weight under water stress condition, as same as, clones 1, 18 and 19 had great behavior under water stress. In addition to most of sugarcane tested clones were not affected by increase the degree of water stress from 100 to 80% of IWL. The LAI, Chl.a and Chl.b traits showed the high correlation with shoot fresh weight, whereas, proline had strong relationships with root fresh weight under sugarcane drought stress.

Sugarcane | Heritability | Genetic Correlation | Phenotypic Correlations