Breeding By Design For Elite Gene In Rice (Oryza Sativa L.) Based On Single Segment Substitution Lines

Rice(Oryza sativa L.)is one of the most important cereal crops,plays an important role in human food security.With the improvement of living standards,rice quality was more and more getten the attention of people.Under natural conditions,rice is vulnerable affected by brown plant-hopper and rice blast,caused the yield reduction,quality dropping.Therefore,breeders want to be able to at the same time improved rice yield,quality and resistance ability.Our laboratory has done a lot of researches on the construction of Single Segment Substitution Lines(SSSLs)and breeding by design.This study based on the former constructed SSSLs and Multiple Segments Pyramid Lines,carrying with related genes(QTLs)of rice yield,quality and resistance to diseases and pests,to carry out the pyramid breeding,and analyze the homozygous pyramids.1.Using of 23 SSSLs and 8 multi-gene pyramiding lines living with elite traits on high yield,grain quality and good resistance to brown plant-hopper(BPH)and rice blast,according to the breeding targets in different hybridized combinations,this study won 56 multi-gene pyramiding lines with multi-elite traits.Among them,nine segments pyramid lines were 2,eight segments pyramid lines were 8,seven segments pyramid lines were 13,six segments pyramid lines were 9 and double segments pyramid lines were 24.2.To get 56 of homozygous pyramiding lines to identify the target genes(QTL)and agronomic traits,and the aggregation effect analysis.Through tests,most elite genes(QTLs)can be detected in the pyramiding lines,and the phenotype were consistent with expectations.The yield related traits such as heading date,tillering number,plant height and spike length,seed setting rate,grain and the grain density,quality related traits of grain length,grain width,gelatinization temperature,alkali nitrate value and amylose content,etc were identified.There are 40 copies of pyramiding lines of HJX74 significantly compared with early heading,there are 3 copies of pyramiding lines significantly improve the effective tillering number per plant and 8 copies of pyramiding lines on the grain density has significantly improved,there are 24 pyramiding lines compared with significant increase in grain,45 pyramiding lines compared with HJX74 significant changes on grain length,in addition,there are 8 homozygous pyramiding lines compared with HJX74 on the theory of production have significantly improved.3.In the homozygous pyramiding lines with rice blast resistance genes qBLAST-11-1 and qBLAST-2-1 were identified,and all materials of rice blast resistance level than HJX74 have different degrees of improvement.At the same time,there are 8 homozygous double segments pyramiding lines with insect-resistant genes(Bph24)were identified,and all materials achieve strong ability of resistance to BPH.This study using Single Segment Substitution Lines with elite genes(QTLs)conducted design breeding,and got a batch of materials in line with expectations.Pyramiding of elite genes(QTLs)can mostly be expressed,basically reached the material yield,quality and ability to resist insect and synergy of improved design expectations,also provides a good material for breeding further to carry out the breeding design.