Optimization Of Maize Haploid Inducing And Doubling Methods And Genetic Studies On DH Lines

Three aspects of optimization of maize haploid inducing and doubling methods and geneticstudies on DH lines were studied in this paper. Firstly, Inbred line JS6-1etc. of maizeparthenogenesis inducer, inbred lines J-1etc., hybrids JNY301etc., S1-S5generations of inbredlines in5germplasm, were studied to explore the haploid inducing conditions and doublingmethods in this paper. Secondly, we based on colchicine and the haploid induced by JS6-1as thematerials to research on the fertility spontaneously restoring of inflorescence and chemicalagents on chromosome doubling of maternal maize haploid. Also four methods (dipping seed,dipping root,dipping bud,injecting)which were used to treat different parts (seed, root, bud,stem tip)of the haploid were studied in the test.Thirdly, based on four inbred lines as femaleparent, six DH lines as male parent, which crossed24hybrids and constituted augmented NCIIdesign to analysis on DH heterosis, combining abilities and heritabilities in three densities,namely60000plants/hm2,75000plants/hm2,90000plants/hm2. Evaluate the yield potential ofDH lines with that crosses yield performance.1. The study on maize haploid inducing rate. The research on maize parthenogenesisinducer inducing haploid indicated that the haploid induction rate had difference in differentmaterials that under the same factors and the same materials that under the different factors.(1)It had significant differences of haploid induction rate in genetype of female parent, had not yetfound a significant correlation between different crossing pattern and the induction rate.(2) S1was the optimal induced haploid generation in five germplasm.(3)Compared with Changchun, itwas better to increase the haploid induction rate in Sanya.(4) It was better to increase thehaploid induction rate in the early pollination.(5) It was better to increase the haploid inductionrate in the below than that in the top of the ear.2. The study on maize haploid doubling rate. The research on the fertility spontaneouslyrestoring of inflorescence and chemical agents on chromosome doubling of maternal maizehaploid indicated that it had differences on the haploid induction of different genotypes in theear of natural fertility,46.49%of haploid ears were naturally fertile in average.J-212(Lancaster×Reid)was the highest (59.09)in the seed setting on per ear,J-211(Reid×Reid) wasthe lowest(33.33%).On the contrary, the FSR of haploid tassel was greatly reduced, the highestwas6.25.%. In chromosome doubling treatment of haploids, the best effect was achieved byroot dipping and injecting seedlings with colchicine, Using this methods, the suitable concentration was0.4-0.6mg/mL, also mixing5%glycerine and3%DMSO.The haploids underthe genotype of Lancaster×Lancaster was strongest on the natural fertility restoration. Weshould adopt injecting method for improving the powder rate with using colchicine that thesuitable concentration was0.6mg/mL mixing5%glycerine and3%DMSO, also root dippingmethod for improving the doubling rate with using colchicine that the suitable concentration was0.4mg/mL mixing5%glycerine and3%DMSO.3. The study on DH lines. Genetic analysis on DH lines for the heterosis value of theyield per plant in3densities were136.6%,103.0%and72.6%,variation coefficient were16.2%,19.9%and25.6%. The data indicated that the yield per plant decreased with the densityincreased, however, the coefficient of variation changed little in different densities. Heterosis ofcombination J22×D12yield per plant was higher than that the control check varietyZhengdan958under the density of60000/hm2. Heterosis of combination J11×D2, J33×D6,J44×D8and J44×D2yield per plant was higher than that the control check varietyZhengdan958,also than that the control check variety Xianyu335under the density of75000plants/hm2. Heterosis of combination J33×D8, J33×D2, J44×D8, J44×D10yield per plantwas higher than that the control check variety Zhengdan958and J33×D8, J33×D2, J44×D12was higher than that the control check variety Xianyu335under the density of90000plants/hm2.The nurtured DH lines have potential use in the future.