Assessment Of Dendrobium Officinale On The Resistance Anthracnose Caused By Colletotrichum Gloeosporioides And Seed Production And Application Of Anthracnose-resistant Lines

Tie Pi Shi Hu (Dendrobium officinale Kimura et Migo) is a rare traditional Chinese medicinal herb with functions of nourishing yin and clearing heat, improving eyesight, lungs, anti-tumor and anti-aging. The outstanding effect makes the market demand rising, while the wild resources are scarce, in order to meet the growing demand, artificial cultivation increased year by year. In 2014, the artificial cultivation areas exceed 50 000 mu. The cultivation facilities resulted in serious pests and diseases. In this study, we investigated field diseases, assessed the anthracnose-resistant D. Officinale lines, producted seed and application of resistant lines.More than 10 cultivation bases were investigated, the results indicated that the anthracnose is one of the most common and widespread diseases of D. Officinale. This disease can occur from defoliation, general stunting and a decrease in stem vigor.On leaves, anthracnose appears on the upper surface in early as irregular, yellowish-white pin point, the spots gradually enlarge and develop a reddish-purple margin around a light-gray center. The center of the spot may drop out, producing a "Shot hole" effect. Leaf spots may merge together producing large grayish dead areas between the veins. The symptom was confirmed to be caused by Colletotrichum gloeosporioides during the morphology and molecular biology detection.Anthracnose disease seriously affect yield and quality of D. Officinale. Therefore, breeding anthracnose-resistant lines was very important. Disease resistance to C. gloeosporioides was evaluted in the ZJU lines in the previous work of our laboratory. It was demonstrated that the three lines (ZJU-1, ZJU-2 and ZJU-4) exhibited resistance to C. gloeosporioides.The pollination mode was established by detecting pollen vigor and stigma receptivity. The TTC(2,3,5-Triphenyltetrazolium chloride) staining method was used to measure the anthers vigor and the Benzidine-H2O2 staining method was used to measure the stigmas receptivity. The results indicated that the development of anthers and stigmas was asynchronous, the highest vigor of pollen were among 8-14 d after flowering, the highest receptivity of stigmas were among 8-21 d after flowering. Combination of anthers flowering 8-14 d and stigmas flowering 8-21 d, the seed setting rate was up to 96.67%.In the interest of inducting and multiplicating of Protocorm-like bodies (PLBs), the medium supplements and incubation densities were optimized. The best medium for the PLBs induction is MS+6-BA 1.5 mg/L+NAA 0.2 mg/L+Potato 100 g/L+Sucrose 30 g/L+Agar 8 g/L, and the induction rate is 19%. When the inoculum density is 1 g/50ml, the proliferation rate of the PLBs is the highest in the liquid medium:MS+6-BA 0.5 mg/L+NAA 1.5 mg/L+Potato 50 g/L+Sucrose 30 g/L, and the proliferation rate is 108%.