Research On Efficient Doubling Technology Of Haploid In Fresh Corn

Fresh corn is one of the important distinctive agricultural products in Yunnan Province.The haploid technology can greatly improve the efficiency of fresh corn breeding,but the low doubling rate is still a problem for haploid technology.In the study,a total of 12 materials from five different genotypes maize(including common sweet corn,super sweet corn,sugary enhanced corn,waxy corn and common corn)were selected,the doubling rate of haploid treated by different methods(seed-soaking,burgeon-soaking and root-soaking),different colchicine concentrations(0.04%,0.06% and 0.08%),different processing times(4h,8h and 12h)and different varieties were study,with the purpose of revealed an efficient doubling technology of haploid which would provide a theoretical reference on fresh corn breeding.The main results were as follows:(1)Effects of different treatments on haploid doubling rateIn the study,the survival rate of haploid treated by different methods decrease with the increase in processing time and treatment concentration.The survival rate of haploid treated by burgeon-soaking(76.4%)was the highest,followed by seed-soaking(68.9%),and root-soaking(55.63%)was the lowest.But the pollen-shedding rate of haploid treated by burgeon-soaking and seed-soaking increase with the increase in processing time and treatment concentration,which decrease with the increase in processing time and treatment concentration for root-soaking with exception of 0.04% colchicine concentration.The pollen-shedding rate of haploid treated by burgeon-soaking(20.4%)was the highest,followed by root-soaking(14.8%),and seed-soaking(13.6%)was the lowest.Synthesizing the data of survival rate and pollen-shedding rate,two optimal treatments were selected,which were 0.08% colchicine concentration with processing 12 h for burgeon-soaking(survival rate 58.62%,pollen-shedding rate 33.33%),and 0.04% colchicine concentration with processing 12 h for root-soaking(survival rate 55.56%,pollen-shedding rate 37.22%).(2)Effects of different varieties on haploid doubling rateThe results of ANOVA showed,the difference of survival rate among 12 varieties were not significant as well as between two treatments,but the difference of pollen-shedding rate among 12 varieties as well as between two treatments were highly significant.The pollen-shedding rate of haploid treated by burgeon-soaking(46.8%)was the highest,followed by root-soaking(25.4%),which both significantly higher than that of natural condition(12.2%).Though the effects of different varieties on pollen-shedding rate of haploid were highly significant,but the performance of pollen-shedding rate for the varieties form the same genotypes of fresh corn were different,the optimal treatments for different varieties were different.