Production Integeneric Hybrids Between Brassica Napus And Brassica Oleracea And Character Comparison Of Progenies

The hybridization occurring between different species, genuses or further genetic relationship individualities is called distant hybridization, and its offspring is the distant hybrid. It is an important way to obtain new germplasm and varieties. The wide hybridizations can break limits of species in some extent, promote genetic introgression and communication of different species, which are effective approaches to transfer useful characters to cultivated crops, to produce new species, to introduce alien gene and create variations. Distant hybridization has been widely used in cabbage breeding and has made many significant results. Many kinds of male sterile lines had been found in B. napus (2n =4x=38), and cabbage contains a good pest-resistant source. We can transferred the dominant cytoplasmic male sterility genes (Eru) to cabbage by interspecific hybridization and backcross. It is a good way to create the middle of materials for insect-resistant breeding.In this experiment, the conditions of ovary culture and embryo rescue of hybrid and the characteristics of their backcross generations were studied. The main results were as follows:1. The results indicated that the best culture medium for the ovary culture of hybrid was 1/2MS+0.2mg/L6-BA. The best DAP of ovary culture to obtain the largest number of seeds was 10d. The best DAP of ovary culture to reach the highest rate of post-germination and have a good growth condition was 12d. The best DAP of embryo culture was 14d. The best culture way was the combination of embryos cultured for 10 days after ovary culture the first 15 days.2. We had obtained hybrids of the B. napus (Eru CMS) and the cabbage by embryo rescue. Hybrid seedlings were performance differently. We obtained 11 true hybrids which identified by flow cytometry and the stigma chromosome counting.3. The fertility and botany characters of F1 and backcross progeny were compared. The results showed that the hybird plants were morphologically similar to parents during the growing periods, while tended to female parent during flowering. But hybrids had stronger growth vigor and higher heterosis. The mosaic leaf hybrid has some variation in leaf structure while the leaf structure of green leaf hybrid was between parents. The stomatal guard cells number of chloroplasts, early flowering stage and floral morphology were all between their parents. Test of the pollen viability showed hybrids bore only non-energied pollens and 100% steriled. Backcross generation could only be obtained through embryo rescue technology overcoming barriers of hybridization.4. The real hybrid from Brassica napus X Brassica oleracea were studied by Polyacrylamide Gel Electrophoresis. The isozyme (SOD, EST, and COD,POD) and protein patterns were also compared with those in parents. Obvious variations were observed in isozymes and protein patterns between parents and the interspecific hybrid. The results show that the SOD and COD patterns of hybrid were similar to Brassica oleracea, while the EST pattern was similar to female parent. The protein pattern was mainly parentally complementary, and also with new bonds with its own characters. The isozyme POD was similar to the protein pattern.5. Backcross generation could only be obtained through embryo rescue technology overcoming barriers of hybridization.It was detected that backcross generation with many ad vantages. Such as:the leaves of seedling stage would not become etiolation when the environment tempreture was low. Sterility was steady.Nectary was normal. Degree of pollen steritity and rate of sterile plants were 100%.