Study On Induced Apomixis In Ramie

Ramie (Boehmeria nivea L.), belonging to Urticaceae Boehmeria, is a perennial herb bast fiber crops. It is one of the most important fiber plants in our country, Currently, varieties and breeding material for the production are heterozygotes. Homozygotes obtained for breeding research and basic research of ramie has a very important significance.To induce apomixes is one possible way to obtain haploid plants of ramie. In this study, we removed the male flowers, put the plants on the bags and sprayed chemical inducers in the flowering period of Brazil NO.4, Guanyuan Ramie, Wuchang big leaf Ramie and so on to obtain seeds of induced apomixes. Then, we identified the first generation of induced apmixis plants. The main results are as follows:(1)The effect of different agents to induce apomixes:Four kinds of chemical inducers also have the ability to induce apomixes. The effect of agent2(30mg/L6-BA+10mg/L2,4-D+100mg/LIAA) is better than other agents:40mg/LMH+2%DMSO+0.1%Colchicine,20mg/LZeatin+5mg/L2,4-D+200mg/LNAA,40mg/L6-BA+5mg/L2,4-D+200mg/LNAA. The effect of agent1was best on "034×047". The effect of agent2was very good on "Brazil NO.4," and "Libo Large Rmaie". The effect of agent4was best on "DouXuan" and "Libo Large Rmaie".(2) The germinating ability and seeding rates of seeds of induced apomixes:The plants that sprayed by agent1had a small number of seeds, which had the poor germinating ability and seeding rates. But The plants that sprayed by agent2produced more seeds,which had stronger germinating ability and seeding rates. The germinating ability and seeding rates of seeds of induced by agent2on Wuchang big leaf Ramie were the highest, and its number was the largest.(3) The test result of ploidy of seeds of induced apomixes using FCM:In the plants of seeds of induced apomixes prudued, there awre more plants of diploid plant, but a few of plants of aneuploidy plant. These aneuploidy plants may be the first generation of induced apmixis plants. The number of aneuploidy plants which were produced by the seeds of induced by agent2on "Wuchang big leaf Ramie" was the more than others.(4) Cytoembryological observation on the process of formation of seeds of induced apomixes:A few induced plants could grow into functional megaspore. and functional megaspore could divide and differentiate into complete embryo, which will become seeds.But,the female flowers of most of induced plants aborted as control plants, these plants had no seeds. The induced plants by agent2had more seeds than others. The plants which were sprayed by agent2on "Brazil NO.4" produced more seeds.Ultimately, The effect of agent:30mg/L6-BA+10mg/L2,4-D+100mg/LIAA to induce apomixes is better."Brazil NO.4" and "Wuchang big leaf Ramie" have better induction effect.