Evaluation And Research Of Breeding Potential Of Two Non-heading Chinese Cabbage Isonucleus Sterile Lines

Non-heading Chinese cabbage(Brassica campestris L.ssp.Chinensis L. Makino)also named as pakchoi, is a variant of cruciferae brassica cabbage, it is an important autumn and winter vegetable in South china, Non-heading Chinese cabbage is a typical cross-pollinated crops with strong heterosis and its utilization route was male sterile and self incompatible.Among them, the cytoplasmic male sterility(CMS) type is an ideal way of heterosis. In this study, the two CMS lines with heterogeneous nuclear of brassica rapa hau and eru CMS were chosen into research, through evaluating the sterility of two CMS types, analysing their heterosis, combining ability and cytoplasmic effects,Evaluating the application value of the two sterile lines and breeding excellent CMS lines with sterility stability, high combining ability and superior hybrid combinations. The main results are as follows:1.The sterility evaluation of two CMS lines in brassica rapa. In this study, we investigated two CMS types by investigating the degree and rates of sterility of the two no-heading Chinese cabbage CMS types, testing pollen viability and observing flower organ morphology, We have identified two CMS types through two years. the results showed that the degree and the rate of sterile plants were all 100%, two CMS lines are no viable pollen or pollen; The Brassica rapa hau CMS have thick stigmas, under the condition of cold and wet weather, and some of them were abnormal with splitting into multiple stigmas, or stamen degenerating into flat structure. The pistil of eru CMS in brassica rapa is much higher than stamen, these stamens degenerate into a white flat structure with no pollen grains. The results show that two CMS lines were stable sterile.2.The genetic diversity analysis of 48 non-heading Chinese cabbage(Brassica rapa)inbred lines. First, SSR molecular makers were used to analyze genetic diversity of 48non-heading Chinese cabbage, The 476 pairs of SSR primers from the Chinese cabbage genome information were selectioned analysing five non-heading Chinese cabbage(Brassica rapa) inbred lines with obvious polymorphism, 114 pairs of SSR primers showed polymorphism with clear and repeating bands,then the 114 pairs primers were used for the PCR amplification 48 non-heading Chinese cabbage inbred lines parental material. Subsequently, clustering analysis was carried out by 329 PCR polymorphism bands. Meanwhile, the agronomy traits and quality traits of 48 non-heading Chinese cabbage inbred lines were analysised. surveyed 15 major agronomic and quality traits including plant height, plant width, a large waist, turnips rough, leaf length, leaf width,petiole length petiole width, leaf, petiole color, waist, yield, dry weight, protein content and sugar content. These data were also used for clustering analysis The results show that the SSR cluster analysis was consistent with clustering traits of the agronomy and quality.13 brassica rapa inbred lines lines were chosed for heterosis, combining ability and cytoplasmic effect analysis according to clustering results.3. Heterosis analysis. In this study, we used two CMS lines and their common maintainer as female parent and 13 inbred lines as male parent for hybridization to produce F1 generation. Then, we analysed the heterosis, combining ability and the cytoplasm effect of 39 F1 hybrids and parents. Heterosis analysis showed that F1 hybrids of the three female lines of have obvious heterosis, but the F1 offspring of of maintainer as female parent had the largest heterosis, the heterosis of F1 offspring of brassica rapa hau CMS as female parent were weakest;4.The results of combining ability analysis showed that: One of the female parent,the maintainer line named brassica rapa 9 has highest GCA, indicating that the maintainer line brassica rapa 9 showed breeding potential as parent material among 13 inbred lines.The brassica rapa hau CMS had lowest GCA,Currently, heterosis potential among 13 inbred lines was insufficient.5.Cytoplasmic effect analysis showed that: Two CMS lines both showed cytoplasm negative effect, But the cytoplasmic negative effect of non-heading Chinese cabbage(Brassica rapa) hau CMS is obvious and eru CMS is not obvious.Among three female parent(two CMS lines and common maintainer line), the maintainer line “brassica rapa nine” was better than two sterile line in heterosis and GCA.So, exploit self-incompatibility for heterosis breeding, in this study, it turned out that,materials with strong heterosis and high combining ability means better breeding potential;In two CMS lines the Brassica rapa eru CMS has stronger heterosis, better combining ability and smaller cytoplasmic negative effects. So it is an excellent CMS types for heterosis utilizations in the brassica rapa.