Study On The Differences Of Flowering And Seed Setting Characteristics Among Different Types Of Male Sterile Lines And Molecular Diversity Of Allo-cytoplasm In Cabbage ( Brassica Oleracea Var.capitata L.)

Cabbage (Brassica oleracea var. capitata L.) is an important vegetable with obvious heterosis. More and more male sterilities were used except self-incompatibility system in the breeding of cabbage hybrid recently. Cabbage and broccoli breeding group of Institute of Vegetables and Flowers (CAAS) was engaged in the research of male sterility in cabbage, including discovery of sterile material DGMS79-399-3, and introduction of cabbage male sterility with radish cytoplasm (Ogura CMSR1, Ogura CMSR2, Ogura CMSR3), cabbage male sterile with black mustard cytoplasm (Nig CMS) and cabbage male sterility with polima cytoplasmic (Pol CMS). At present, stable male sterile lines had been bred by multi-backcrossing for DGMS and Ogura CMSR3. At the same time, the differences of flower characters and seed yield between the two different male sterile lines were found during seed producing, but until now there is no further investigation.The research consists of two parts: the first, the materials of self-bred lines (SI) 02-12, 01-20 and their multi-backcross generation, dominant genic male sterile lines (DGMS02-12 and DGMS01-20) and cytoplasmic male sterile lines (CMSR302-12 and CMSR301-20) were researched. Floral characters, the proportion of dead buds in early flowering period, bee pollination and seed yield between DGMS and CMS were investigated in order to assist their application. The results were as following:1. Dead buds in early flowering period: The survey of 2008 and 2009 showed that there was significant difference on dead buds of the first branch between DGMS and CMSR3, and the different degree varied in different materials and years. In greenhouse, CMSR302-12 was 34.7% higher than that of DGMS02-12 for the proportion of the dead buds at the first branch; CMSR301-20 was 29.4% higher than that of DGMS01-20. In open field, it was 89.2% and 64.7% higher, respectively.2. Flower character: The differences of stamen length, bud diameter and nectary surface area between DGMS and CMSR3 were extremely significant. The differences of corolla diameter, anther length and nectar volume of single flower between DGMS and CMSR3 were significant.The results of the two years showed that the anther length of DGMS02-12 was 77% higher than CMSR302-12 and DGMS01-20 was 60% higher than CMSR301-20, and it was 12.4% and 10.2% higher at the petal length, 23% and 8% higher at bud diameter, 76.7% and 66.7% higher at the nectary surface area, 84% and 33.5% higher at single flower nectar volume, 16.3% and 22.9% at the corolla diameter, 10.7% and 3.5% higher at the anther length.3. Bee pollination: The differences of visiting bee number and the time of bee stay on the flower between DGMS and CMSR3 were extremely significant. Visiting bee number of DGMS02-12 was 28.2% higher than CMSR302-12 and these of DGMS01-20 was 19% higher than CMSR301-20, 50.8% and 63.9% longer at the time of bee stay on the flower. Moreover, correlation of visiting bee number with flowering characters was: corolla diameter (r=0.976, P <0.01)> nectar volume (r=0.944, P <0.01)> nectary approximate surface area (r=0.914, P <0.01) > petal length (r=0.906, P <0.01).4. Seed setting character: The difference of seed yield between DGMS and CMSR3 was extremely significant and the difference degree varied in different materials and plots. Seed yield of DGMS02-12 was 62.8%-135.1% higher than that of CMSR302-12, these of DGMS01-20 was 16.7%-43.1% higher than that of CMSR301-20.Dead buds at the stage of early flowering directly reduced the number of pod; floral organs and volume of nectar affect the bees visiting flowers; bee foraging times and visiting hours affect pollination effect. The three main aspects in the two types of male sterile lines leaded to the differences of seed production between DGMS and CMSR3. The main factors affecting seed yield included: corolla diameter (r=0.907, p<0.01), the number of visiting bees (r=0.893, p<0.01) and the proportion of dead buds at the first branch (r=-0.891, p<0.01).The second part of the experiment: In order to avoid the potential risks of the single cytoplasmic hybrids, Our research group introduced many different types of CMS, which of them was difficult to distinguish according to morphology. Distinguishing the type of alien-cytoplasm male sterile lines was researched using mtSSR and cpSSR. The results were as following:Respectively, 30 and 19 polymorphic primers were screened from 151 pairs of CpSSR and 182 pairs of MtSSR in fourteen cabbage materials, and percentage of polymorphic accounted for 19.87% and 10.44%. According to the clustering analysis, five types of cytoplasm male sterile lines were identified respectively. Six types of cytoplasm male sterilities (Nig CMS, Ogura CMSR1, Ogura CMSR2, Ogura CMSR3, Ogura CMSYouxiu, Pol CMS) were unambiguously identified using just three sets of primers (mtSSR2, cpSSR81, cpSSR138 ) in cabbage male sterile lines. Moreover, diverse fragments had a highly sequence homology between with the corresponding sequence of Arabidopsis thaliana or B.rape respectively. Therefore, the method that identified the types of cytoplasm male sterility using total genomic DNA and specific mitochondrial or chloroplast genome SSR was feasible.