Study On Autotetraploid Induction With Trifluralin And Colchicine And Microspore Culture In Radish (Raphanus Sativus L.)

Radish (Raphanus sativus L.) is an important vegetable which originated from China, and the germplasm resources are very abundant. The radish microspore culture technique could obtain homozygous planets quickly, which could cut the breeding time. Polyploidy breeding could improve the quality of crops. As far as we know, the embryo induction and regeneration rate were low in radish, and the efficiency system of radish tetraploid induction was still distempered. The method that trifluralin was used in tetraploid induction was not reported so far in radish, especially.Compared the effect of tetraploid yield between colchicine and trifluralin, and so did the different method of ploidy identification, which provide theory basis for radish tetraploid induction and ploidy identification. Besides, the genotypes with ability of embryo formation were screened and researched the factors which influenced the embryo induction rate in microspore culture.In the experiment of radish tetraploid induction, we got tetraploid planets with0.1%colchicine treating the growing point in the6donor genotypes, of which the highest induction rate were Nau-xht and Nau-zhqh, both16.67%. However, the highest induction ratio of40%, which were treated with0.2and1mmol/L trifluralin, respectively, were obtained in the two lines, Nau-dy13and Nau-xbch. We found that the teraploid induction effect of trifluralin was better than colchicine. There were significant differences between tetraploids and diploids in stomata size, chloroplast number in guard cell, flower size, pollen size and germination rate. It could be concluded that the ploidy level of mutant plant could be determinated by combination of morphological, cytological identification and chromosomes counting. This study indicated that trifluralin treatment was an effective method for tetraploid germplasm induction in radish.11radish cultivars were applied onto the growing point of the planets by using0.1%colchicine and all varieties obtained tetraploid. The highest induction rate was33.33%and the lowest was16.67%. Tetraploid was identified by the plant morphology, stomata characterization, pollen grains and chromosome counting.In the study of radish microspore culture, Seven genotypes which could produced embryos were obtained. The somatic embryos from "09-4265" developed to regenerated planets finally. The microspores were at the uninucleate stage when the the length of buds was between3mm to4.5mm. The addition of0.2mg/L2,4-D and0.1mg/L6-BA in NLN-13could improve the induction rate of embryos.