Study On The In Vitro Culture And Polyploid Induction Of Mulberry (Morus Alba)

Mulberry fine varieties Guisangyou62and Guisangyou12were taken as test materials to study in vitro culture and polyploid induction of mulberry. For the study of in vitro culture, the effects of different sterilization methods on explants sterilization, different basic mediums and hormone treatments on asepsis bud multiplication, and different hormone combinations on asepsis plantlets root induction were explored. Therefore, the suitable explants sterilization method, bud multiplication medium and root induction medium were selected, and the technology system of in vitro culture of Guisangyou62and Guisangyou12was established, in which it could provide technical reference for industrialized breeding of Guisangyou62and Guisangyou12. For the study of polyploid induction, effects of different colchicine concentrations treating the same time and one colchicine concentration treating different time on polyploid induction were studied, and morphological identification and cytological identification were conducted on the variant plants obtained.The main results were as follows:1. The best sterilant combination for the seed explant sterilization was0.1%HgCl214min+10%NaClO12min.75%Ethanol was not suitable for the sterilization of mulberry seeds. MS medium without GA3was better for plantlet induction of mulberry seeds.2. In the comparison test of three auxins(IBA, NAA and IAA), the best auxin for asepsis bud multiplication was IAA; in the comparison test of five basic mediums(MS, B5, N6, Miller and White), the best basic medium for asepsis bud multiplication was MS medium. 3. The best medium combination for asepsis bud multiplication of mulberry was MS+IAA0.2mg/L+6-BA2.0mg/L+CPPU0.8mg/L+sucrose30g/L, with the bud multiplication multiple peaked at5.30for Guisangyou62, and5.15for Guisangyou12.4. The best medium combination for root induction of mulberry asepsis plantlets was1/2MS+NAA2.0mg/L+PP3331.0mg/L, and the rooting rate reached100%for both mulberry varieties.5. The effective method for mulberry polyploid induction was:treating asepsis bud growing points with0.1-0.3%colchicine solution for3days, or treating asepsis bud growing points with0.3%colchicine solution for2-3days.6. By comparing the polyploid plants with diploid ones in morphology, polyploid plants of mulberry grew slowly, with thicker stems, more deep green in color, abnormal leaves appeared, and larger leaves in later stage of growth. Cytological identification showed that the chromosome number of tetraploid plants was2n=4x=:56, while that of diploid plants was2n=2x=28. The differences of stomata number and stomatal guard cell size were significant between tetraploid and diploid mulberry plants.