Study On Producing Double Haploid Of Wheat Between Wheat And Maize By Wide Hybridization

Haploid embryo is obtained due to the chromosome elimination of maize in wheat(Triticum aestivum L.) and maize(Zea mays L.) crosses. Producing a DH system by young embryo culture and chromosome doubling is a high efficiency way to haploid breeding in wheat.But the problem is that frenquent of producing embryo is still not perfect as we want at persent. Most researchers induced the embryo by general cross methods in field, but the effect was influnced seriously by environment factors. The purpose of this study was to investigate way of creating wheat DH plant groups by using isolated culture methods in green house and general cross methods in field for inducing wheat×maize haploid, and by chromosome doubling with colchicines solution. The results was showed as follows:1. In order to meet the time of flower between wheat and maize, Using manual vernalization and planting wheat by stages in Summer; or growing maize in the green house and planting by stages in Winter.2. The frenquencies of embryo formation in different cross combinations of wheat varieties was significantly different. The highest combination D021/Yang9 was 26.4%, and the lowest one D027/C98 was 2.6%. The frenquencies of embryo formation of different populations of maize was Puffed maize(9.9%)>Glutincus maize(8.9%)>Common maize(8.2%)>Sweet maize (4.6%).3. The effect of 3 kinds of concentration of 2,4-D solution to the frenquencies of embryo formation was different too and it was highest when the concentration of 2,4-D solution was 100mg/L. In addition, 2,4-D repeating treatment in the frenquencies of embryo formation was better than no repeating.4. Average frenquence of producing haploid was isolated culture methods(23.6%) at T≥20℃ was higher than the one of general cross methods in filed (18.1%), and the frenquence of producing haploid was the highest when isolated culture 14 days in the condition which temperture was 20℃,illumination was 3000Lx12h/d,and relatively humidity was 70%.5. Enough effective accumulated temperature (T>10℃) was necessary to high frenquent of producing haploid after pollination, and effective accumulated temperature (T>10℃) to the highest frenquence of producing haploid should be in the range of 187.9~254.9℃; fitting environment temperature was important factor after pollination, and the condition was the best when environment temperature was 20℃.6. Soaking roots of seeding for 5h using colchicines solution with concentration of 250mg/L,500 mg/L ,750 mg/L ,1000 mg/L,the frequencyes of doubling were 51.9％,83.2％,86.4％,82.9％ respectively； Efficiency of doubling were 46.1％,68.8％,71.7％,70.9％. Both of the effects were the best of the colchicines solution with concentration of 750mg/L. Afforting continuance O2 when Soaking roots of seedling for 5h using colchicines solution, the average frequencyes of doubling was 79.9%, which was higher than the average frequences of doubling without afforting continuance O2 when Soaking roots of seedling. Efficiency of doubling(66.1%)when affording O2 was higher than the one(62.2%) without afforting continuance O2 too.