Influence factors of tissue culture and rapid propagation efficiency of papaya

Stem segments of papaya were used as explants to establish the aseptic system and compare the effects of different hormone combinations on the primary culture of axillary buds. The second generations of buds were used as test materials in the subculture,to examine the effects of 6-BA,KT,NAA and GA on the proliferation culture of papaya by using the orthogonal experiment design L9(34),and the multiplication medium was optimized. And the rooting techniques of papaya were studied too. The results showed that:(1)Rapidly immersed with 75% alcohol for 20 s plus 0.1% Hg Cl2 for 25 min after the pretreatment was the better disinfection method with the contamination rate of 16.67%,the germination rate of 77.94%,and the browning rate of 13.33%.(2)The best medium for primary culture was MS + 6-BA 0.5 mg/L + NAA 0.1 mg/L + sucrose 30 g/L with the induction rate of axillary buds up to 76.67%.(3)The most suitable medium for proliferation and plant height was MS + 6-BA 0.5 mg/L + KT 1.5 mg/L + NAA 0.5 mg/L + GA 0.6 mg/L,the multiplication coefficient was 6.87 and the plant height was 3.31 cm after 30 d,and the effects of different hormones on the multiplication coefficient and plant height of papaya were all ranked in the following order:6-BA GA KT NAA.(4)The best medium for early proliferation culture was MS + 6-BA 0.5 mg/L + KT 0.5 mg/L + NAA 0.5 mg/L + GA 0.6 mg/L,and the best medium for middle and late proliferation culture was MS + 6-BA 0.5 mg/L + KT 0.5 mg/L + NAA 0.3 mg/L + GA 0.6 mg/L.(5)The best rooting medium was 1/2MS + IBA 0.5 mg/L + NAA 0.1 mg/L + sucrose 30 g/L + AC 0.1% with the rooting rate up to 65%,the root number per plant up to 4.68,the survival rate of rooting seedlings over 60%.