Study On Tissue Culture And Salt-tolerance Mutation Breeding

Potato (Solanum tuberosum L.), which is one of most important food crops in agricultural production plays a very important role in people's life, and the saline soil could seriously affect potatoes's growth and productivity. Therefore, breeding the salt-tolerant varieties of potatoes does not only have a very important economic value but also an important social value.In our study, we built up four culture systems of potatoes tissue using potato 1, 2, and 3, in 4 as the material, through meristem tip, and differentiation medium was MS + BA 2mg / L + NAA 0.1mg / L + GA30.1 mg / L +3% +6% sucrose agar.We use the potatoes stems as the material, 1.0% NaCl as the selection pressure, through ⁶⁰Coγ-ray radiation,EMS treatment and composite method to induce salt tolerant mutant, and obtained the salt tolerant mutant of 1.0% NaCl named WL-1. At the same time, we studied the effection of ⁶⁰Coγ-ray radiation,EMS to the growth of potato stems and the mutation rate. Low dose (10Gy) of ⁶⁰Coγ-ray radiation could promote the stems'growth, with the increase of the radiation dose; the inhibition to the plantlet is also increased. Sensitivity of terminal bud is lower than lateral bud, the suitable doses for potato stems were 20Gy, and lethal dose were 40 Gy. The damage of low dose (0.1%) EMS treatment is minimal, and the high dose or long time EMS treatment could cause stem tip and stems whitening, lose the ability of growth, the suitable doses and treatment time for potato stems were 0.7%+4h, and lethal dose were 1.0%+3h.Through outside indexes analysis,biochemical indexes analysis and salt stress of pot cultivation, evaluated the salt tolerance of WL-1. The results showed that: as the NaCl concentration higher than 0.6%, the plant height,proline content,chlorophyll content of salt tolerant mutant WL-1 is significantly higher than control group, MDA content is lower. Results of SDS-PAGE showed that: One of WL-1 expression content is higher than control group.The RAPD text revealed that the gentic similarity between WL-1 and Zhong 3 was 0.707; so all the evidence mentioned above proved that WL-1 is salt tolerant mutant.