Molecular Improvement Of Resistance To Clubroot Disease Of Parental Lines In Brassica Napus

Rape is the most important oil crop in our country.Recently,clubroot has broken out seriously,causing great harm and bringing major hidden dangers to the strategic safety of edible oil.The area of clubroot is nearly 10 million acres and it is developing rapidly.The breeding and utilization of new rape varieties resistant to clubroot is considered to be the most effective and economical prevention and control strategy.However,there are many different physiological races of plasmodiophora brassicae,and they grow together in the field.Therefore,the resistance of new varieties containing a single resistance gene locus can be easily broken through for a long time.Consequently,exploiting germplasm resources containing different resistance genes and breeding or clustering new rape varieties with different resistance sites are extremely important for stabilizing the production of rapeseed.The research group’s early resource innovations contained PbBa8.1 and CRb disease resistance locus,respectively,breeding the first batch of new clubroot disease-resistant Brassica napus new varieties HS5 R and Huayouza 62 R.On this basis,this study continues to use the above two different sources of resistance,using molecular marker-assisted selection(MAS)technology,combined with field resistance identification,etc.,the disease resistance locus PbBa8.1 and CRb were respectively introduced into the backbone parent of Brassica napus and Huayouza 62 sterile line,and the following research results were obtained:1.Obtaining homozygous disease-resistant backbone parents containing disease-resistant sites PbBa8.1 and CRb,respectively.In this study,using molecular marker-assisted selection,the PbBa8.1-containing rapeseed resistance source was backcrossed and selfed for multiple generations with the excellent cabbage rape varieties ZY 50 and ZS11 or the excellent backbone parents HS,LMT,Bing409 and W3.Combining field resistance identification and quality analysis,a new homozygous disease-resistant line with good quality was obtained in the BC4F3 or BC5F3 generations;the CRb-containing rape resistance source was used to molecularly modified the excellent cabbage rape variety Zheyou 50 and the excellent backbone parent HS and high-quality homozygous disease-resistant materials was obtained in the BC4F3 generation.2.Obtaining homozygous resistant Huayouza 62 sterile lines containing disease-resistant sites PbBa8.1 and CRb,respectively.Using molecular marker-assisted selection,the PbBa8.1-containing rape resistance source and Huayouza 62 sterile line were backcrossed and selfed for multiple generations,combined with field resistance identification and quality analysis,a new and pure sterile line of high-quality with resistance to disease was obtained in the BC3F2 generation;Using a rape resistance source containing CRb to molecularly improve the resistance to clubroot of Huayouza 62 sterile line,and a homozygous disease-resistant sterile line with good quality in the BC2F2 generation was obtained.In short,the above-mentioned test results provide good materials for the selection and breeding of clubroot resistance in Brassica napus,and at the same time an important foundation for the polymerization breeding for resistance to clubroot was provided.