Abstract:

To establish an efficient and rapid propagation system for virus-free stem tip tissue of sweet potato，this study utilized sweet potato variety Xinxiang as the material and conducted a systematic investigation into the effects of various factors on virus-free tissue of Xinxiang sweet potato stem tips. The experiments included six disinfection protocols for explants，ten MS culture media containing different mass concentrations of 6-BA，NAA，and GA₃，as well as three sucrose mass concentration gradient treatments. Results showed that the optimal explant disinfection was 6 minutes of 75.0% ethanol+0.2% sodium hypochlorite，achieving a contamination rate of 17.8% and survival rate of 62.2%，balancing sterilization effectiveness with explant viability. Hormone tests revealed that A1 medium（MS+0.50 mg·L^-1 6-BA+0.10 mg·L^-1 NAA）had the highest callus induction rate（80.00%），B1 medium（MS+0.05 mg·L^-1 6-BA+0.10 mg·L^-1 GA₃）showed the highest rooting rate（73.33%），C3 medium（MS+1.00 mg·L^-1 6-BA+0.20 mg·L^-1 NAA+0.20 mg·L^-1 GA₃）demonstrated the best germination rate（62.22%），and achieved the highest seedling survival rate（55.56%）. The optimal sucrose mass concentration was 25 g·L^-1，yielding a 60.00% bud germination rate and 55.56% seedling survival rate，with robust plant growth. Furthermore，the tissue culture propagation of seedlings achieved optimal results using a 1/2 MS medium combined with 0.10 g·L^-1 Huabao No.5 culture medium. The virus-free Xinxiang seedlings tested negative for both sweet potato mosaic virus（SPFMV）and sweet potato chlorosis dwarfing virus（SPCSV），with a 100% virus elimination rate. The sterilization protocols，medium formulations，and sucrose mass concentrations identified in this study provide technical support for industrial-scale production of Xinxiang virus-free seedlings.

Key words: sweet potato, stem tip, virus-free, tissue culture, efficient and rapid propagation system