Study on the Differences in Root System Development between Beihong and Muscat Hamburg Tissue Culture Seedlings

Beihong exhibits strong disease and frost resistance, allowing it to overwinter safely without soil burial in most wine-producing regions of China. It also possesses high fruit quality, making it suitable for winemaking. However, its rooting ability is poor in production. This study utilized tissue culture techniques, designing nine groups of tissue culture plantlets with varying concentrations of sucrose, NAA, and IBA through an orthogonal experiment to induce rooting. The Eurasian variety Muscat Hamburg, known for its ease of rooting, was used as a control to investigate the differences in rooting between the two varieties. The objective was to provide a theoretical basis for the propagation and rooting of Beihong in practical production. The number of main roots, number of lateral roots, and main root length for both varieties were measured at 20, 30, and 40 days after rooting treatment. Additionally, the levels of ABA, GA3, IAA, and tZ in the roots of both varieties were analyzed at five treatment stages (1, 2, 5, 6, and 8). The synthesis of IAA-related receptors and carrier-related genes in the roots was also quantified. The results indicated that Beihong exhibited a higher rooting rate and superior rooting index compared to Muscat Hamburg. Significant differences in endogenous hormone levels were observed between the roots of the two varieties. The correlation coefficient between the IAA level and root indices was high in Beihong but low in Muscat Hamburg. The expression levels of IAA-related genes in the root systems of both varieties showed considerable differences, though some similarities were also noted. Gene expression varied across the three observation periods. This study provides a theoretical foundation for improving the rooting process of Beihong.