| Self-incompatibility widely exists in plant kingdom and causes an extensive concern of botanist and molecular biologist. It facilitates the evolvement and extends the variation; hence it has a promising prospect in breeding, especially in hybridization. Some researches show that vegetative Self-incompatibility is determined by S-locus, many S-genes and their expressive products have been cloned. Recent studies show that some others genes relate to vegetative Self-incompatibility besides S-locus genes, such as ARC1, SLR, aquaporin, THL1/THL2, MLPK etc, more and more results in Brassica oleracea and Brassica rapa suggested that MLPK which cooperate with s-genes while not as the same participate in the signal transduction of SSI. Others scholars think SSI is controlled by at least two genes, one is S-locus, the other is the suppressor of S-locus (sp). Therefore, to understand the complex molecular mechanism and genetic is very important and interesting. In this paper, we try to elucidate this problem from two aspect with material1. Discussion of genetics of SI line and its maintainer line 89008 and 91806 of Brassica napus.In this study, we use the SI line (SI1300) and its maintainer line (89008) as parents and build Fi(SI1300 × 89008) population, F2(selfed population of SI1300 × 89008)population, two BCl[BC1 father population: (SI1300×89008) ×89008 and BC1mother population: (SI1300×89008) ×SI1300]populations and their segregation populations. In F2 population, SI/SC=9/7; in BC1father population, SI/SC=1/1; in BC1 mother population, SI/SC=3/1 and there are SI individual in SC segregation population, this result can' t be explained by former genetic model. Therefore we put forward a new genetic model: There are at least two loci controlling the self-incompatibility of SI 1300: one is the S locus, with dominant and recessive relationships between the S alleles, and the other is the suppressor (sp) of the S locus. The sp locus is genetically diffeent from the S locus, and also shows dominant and recessive relationships between the sp alleles. From the hypothesis it is supposed that SI1300 has the genotype S1S1Sp1Sp1, and its maintainer has the genotype S2S2SP2SP2 where S2 is dominant over S1, S1 and S2 can be suppressed by Sp2 and S1 can suppress S2 but not S1, but neither of S1 and S2 can be suppressed when Sp1 and Sp2 exist together. This model can explain the segregation of SC and SI in my experiment. It should be tested with other materials and be illuminated in molecular level.2. Development molecular maker of Brassica napusWe take SI line (SI1300), its maintainer line (91806) and F2 population of SI... |
