The Research Of Resistance To Bacterial Wilt And Male Sterility Characteristic In Eggplant Rootstock Germplasms

In eggplant production, grafting cultivation is widely used to prevent soil borne diseases such as bacterial wilt disease, and breeding for disease-resistant rootstocks is the basis of grafting cultivation. However, there are few varieties of eggplant rootstocks which are self bred in China, and lack of systematic researches on the germplasm resources of the rootstock. This study used 16 eggplant rootstocks as materials and the main agronomic characters of the materials were observed and classified. At the same time, the thesis identified the resistance to bacterial wilt by using artificial inoculation method,4 male sterility germplasm resources were also studied. The results clearly indicated the diversity of eggplant rootstock germplasm resources and the resistant difference to bacterial wilt, exploring the male sterility characteristics on rootstocks. The study laid a foundation for the rational utilization of the disease resistance and male sterility.The main results were as follows:1. According to the fruit weight and other 20 main agronomic traits, the botanical classification of 16 eggplant germplasm resources was made clear. All the materials were divided into 5 species, including S. torvum Swartz, S. integrifolium Poir, S. nienkui Merrill et Chun, S. indicum L and S.melongena Linn. Small differences existed during S. torvum Swartz, while S. integrifolium Poir had a certain distinction between stem thorn, leaf thorn and fruit characters, which belonged to different ecological types.2. The study identified the resistance to bacterial wilt of eggplant rootstocks by artificial inoculation in seeding age.11 materials (J07, J08, J12, GY121, W07, X07, S07, C, J04, J05, J13) had high resistance,4 materials (J09, J10, J11 and J61) had resistance to bacterial wilt. All the tested materials had good resistance. The bacterial wilt disease index clustering analysis results was similar to morphological classification, but there were also differences which showed that the same kinds of eggplant rootstock to bacterial wilt resistance level was relatively close, but bacterial wilt resistance and rootstock species were not perfectly correlated.3. We used C, J61, S07, W07 as rootstocks, susceptible cultivar Rf as scion and identified the resistance to the bacterial wilt of grafting seedings. The results showed that 4 grafted seedlings disease index were lower than that of self-rooted Rf, which indicated that grafting played a certain effect of preventing. Among them, the grafted seedlings Rf/S07 and Rf/W07 reached resistance level to bacterial wilt.4. To explore the anther and pollen viability of 4 materials (J04, J05, J09, J10), the results found that the anthers of 4 materials were not obvious morphological abnormalities, and the dispersal of pollen was normal. Pollen staining rate was 1.16%-4.15% by TTC staining. Pollen germination rate was 0.14%-0.96%, which showed that 4 germplasms of pollen viability were low, and they had the characteristics of male sterility.5. The anther development of male sterile and fertile materials were observed by paraffin sections. The results found that there were differences in the anther structure. In the third flower buds, male sterile materials connective parenchyma cells were disintegrated earlier than that of fertile material. When flowers opened, the connective parenchyma cells were disintegrated and shrank into ribbon in male sterile materials, but fertility varieties connective parenchyma cells remained intact. The disintegration of connective cells may have an effect on the pollen abortion.6. Observation on meiosis behaviors of pollen mother cells, the results found that there were laggard chromosomes, chromosome bridge and other abnormal behaviors in male sterile germplasm anaphase I, metaphase I and anaphase II, and the number of abnormal behaviors in anaphase I were more than other periods, Therefore, it was considered that sterility abortion period mainly existed at anaphase I, and the abortion phenomenon was caused by the abnormal chromosome behavior.7. Scanning electron microscopic observation of male sterile and fertile materials of pollen, the results showed that all materials of pollen grains were prolate, and the surface ornamentation were granular with 3 germination ditches. There was no significant difference in appearance and surface characteristics between male sterile and fertile materials. The rate of abnormal pollen in male sterile materials was 84.94-95.47%, the polar axis length was in 33.24-34.19μm and the equatorial axis length was in 19.07-19.35μm. But the cultivars pollen polar axis length of 33.75-41.90μm and 18.10-29.38μm as the equatorial axis length, The pollen grain of sterile germplasm was significantly smaller than that of fertile cultivars.