Molecular Identification Of The Purity Of‘Tailv 1’ Broccoli Seeds And The Development Of Seed Coating Technology Against Damping Off Of Broccoli

At present, industrial seedling production of broccoli( Brassica oleracea var. Italica Planck)gradually become the predominate breeding technique for its increasingly enlarged cultivated area. Butthis industry was restricted by seed purity and high incidence of damping off. This study on one hand authenticate the purity of 112 hybrid cultivars by using SSR mark and field investigating,on the other hand exploit the seed pelleting possessed damping-off resistance,in order to find out an exact and rapid way of purity identification and an efficient method to relieve the damping-off. Main results shown as follows:1. Totally 346 bands were amplified by 114 SSR primer pairs,with being 12.4 bands per pair. Polymorphic rate of each primer pair was among 5.1%-84.6%,with being 30.7%by average.2. Difference existed between the results from purity research of field investigation and SSR mark experiments. According to filed approbation,108 broccoli cultivars showed the typical characters of ‘Tailv 1’ while 4 cultivars showed difference,lead to 96.43% of purity. Through SSR mark identifying, 107 broccoli cultivars showed complementary bands while 4 cultivars didn’t,lead to 95.5% of purity. Consistency of both identifications was 99.1%.3. Pythium aphanidermatum was found as the main bacterium to cause damping-off,through ribosomal DNA internal transcribed interval(ITS) sequence analysis to the broccoli pathogen which was gained by general tissue separation.4. After artificial infection of pathogenic bacteria,emergence rate, damping-off incidence and planting percent of no-coating seeds(CK) was 44.67%,31.3%,28.7%,respectively; and coating with 0.6% mefenoxam was 67.34%,9.87%,61.3%,respectively.Each of above traits showed significant difference at P<0.05, suggested the efficient damping-off remission and seedling facilitation of 0.6% mefenoxam coating. In addition,control effect of coating with 0.6% mefenoxam was significantly greater than coating with pyraclostrobin or compound coating with mefenoxam and pyraclostrobin(P<0.05)through comparative analysis. Hence,it isconcluded that 0.6% mefenoxam coating treating was efficient and recommendable to control damping-off of broccoli.