植物育种学课件（PPT 76页）.pptVIP

2.3 The function of induced mutation breeding： Increase the rate of mutation，expand the range of mutation，produce new traits and new type that don’t exist in nature； Break the linkage of traits，accelerate the recombination of gene； Change some traits coded by one gene effectively； Can be used simply，fasten the stable rate，shorten the time of breeding； Enhance the stress resistance，improve the quality of crop. Increase the rate of mutation，expand the range of mutation，produce new traits and new type that don’t exist in nature； The rate of spontaneous mutations is very low, usually one out of million for an individual gene. The rate of induced mutations is much higher than spontaneous mutations (from 100 times to 1000 times) Can be used simply，fasten the stable rate，shorten the time of breeding； propagated by seed，can be stable in F3，and the new variety can be bred in 3~6 year; propagated by vegetable organ，can be propagated to produce uniform mutation after the identification of desirable traits pure line after being induced, shorten breeding time greatly. 3.2 The methods of physical mutagents 照射诱变.avi 3.2.1 materials： seeds, plants, pollen, egg cells ovary, gametes, zygote, embryo、asexual reproductive organs. Hybrid materials . 3.2.2 methods： (1)outer radiation ：X-rays, γ-rays, neutron operator. (2) inner radiation：32P, 35S, 131I, 14C, 3H, Na2H32PO4. by injection, or dipping in mutagens浸泡物理诱变.avi. (3)Eating method：by applying mutagenic solution into plant growth medium which is absorbed throng roots. 3.3 the dosage of mutagents辐照剂量.avi 3.3.1 radiation intensity： mCi or μCi，1 mCi=10-3Ci and 1μCi= 10-8Ci. 3.3.1 radiation dose： is determined by the intensity of the radiations and length of the exposure. 3.3.1 radiation dose： can also be defined as the amount of the energy absorbed per mass of irradiated matter at the point of interest （erg/g）. rad (radiation absorbed dose) 1 rad = 100erg/g =10-2joule/kg