Evaluation Of Breeding Lines From IRRI And Development Of Multi-Resistant Restorer Lines

In order to expand germplasm resources and rich genetic resources in rice breeding,165rice breeding lines (new lines for shuttle breeding in Africa) introduced from IRRI (International Rice Research Institute) were planted in Hubei in2011and2012. The resistance against bacterial leaf blight, resistance against blast, resistance against brown planthopper, main agronomic traits and rice quality were comprehensively evaluated. In this study, several restorer lines and combinations with multi-resistant against rice bacterial blight and blast and high-yield were selected by using Molecular Marker-assisted Selection (MAS) and gene pyramiding. The main results were as followed:1. The resistance identification result of introduced linesThe resistance identification results showed that there were eight lines with resistance to brown planthopper,11lines with moderate resistant to brown planthopper;60.6%of introduced lines were highly resistant or resistant against the epidemic strain (ZHE173) of Xoo (Xanthomonas oryzae pv.oryzae) in Yangtze Valley rice areas,24.9%of introduced lines were highly resistant or resistant against the epidemic strain (GD1358) of Xoo (Xanthomonas oryzae pv.oryzae) in South China rice areas,40lines showed highly resistant or resistant against both ZHE173and GD1358;14lines showed resistant or moderate resistant to blast in Yichang nursery and Enshi nursery.2. Agronomic traits and yield investigation of introduced linesIntroduced lines seeding-heading days ranged from75to129d,86.1%of lines distributed in90～110d; The plant height ranged from94.8to161.0cm,72.1%of lines distributed in100～120cm. The effective panicles per plant ranged from8to19piece,64.9%of lines distributed in12～16piece. The spikelets per panicle ranged from74to205grain,72.7%of lines distributed in90～130grain. The seed setting rate ranged from32.3%to86.5%,75.8%of lines distributed in60%～80%. The1000-grain weight ranged from16.4to32.7g,69.7%of lines distributed in22～26g. The yield per plant ranged from3.5to37.1g,77.0%of lines distributed in20～30g.3. Rice quality analysis of introduced linesThe rice quality analysis of64introduced lines showed that, milling quality of major lines were all-good, brown rice rate of63lines reached above the3rd level of national standards (higher than75.0%), head rice rate of56lines reached above the3rd level of national standards (higher than52.0%); the chalky grain rate and chalkiness degree were slightly high, chalky grain rate of27lines reached above the3rd level of national standards (lower than30.0%), chalkiness degree of15lines reached above the3rd level of national standards (lower than5.0%), ratio of length and width of all lines were larger than2.8; the amylose content was slightly high,16lines reached above the3rd level of national standards (15.0%-24.0%); the gel consistency were very soft,55lines reached above the3rd level of national standards (shorter than50mm).4. Comprehensive analysis of resistance, agronomic traits and rice quality of introduced linesSynthesize all the results of resistance identification, agronomic traits investigation and rice quality analysis of introduced lines,6lines (IR73931-1-1-1, IR72906-32-1-3-3, IR80404-28-2-3-2, IR80916-56-3-3, IR81178-29-2-3-2, IR82574-573-2-1) were chosen as excellent germplasm with better resistance, agronomic traits and rice quality.5. Nine multi-resistant gene pyramiding lines, including3lines having combination of genes Pi2+Xa7+Xa21,1lines having combination of genes Pi1+Pi2+Xa21,3lines having combination of genes Pi2+Xa21,2lines having combination of genes Pi2+Xa7were Developed. The resistance identification results showed that all the pyramiding lines were highly resistant or resistant against both bacterial leaf blight and blast. The agronomic traits investigation and rice quality analysis indicated that the pyramiding lines have the similar performance with parents, but not as good as the control.6. Eight combinations with high-yield and multi-resistant were selected. Chuannong1A/SL11340-28, Chuannong1A/SL11341-51and Chuannong1A/SL11341-85were average over yield the control by5.9%, and they were highly resistant against both bacterial leaf blight and blast.