| Rice blast is one of the most devastating diseases for yield in rice production,it can cause 15% cut.the most economical and reliable way in rice blast control is breeding new varieties which have broad spectrum and durable resistance of rice blast resistant.Hybrid Rice Variety “Fengliangyouxiang No.1”have the features as high yield,high-quality and moderate growth period,but it's yield and quality maybe affected greatly by the high susceptibility to the disease which caused by Magnaporthe grisea.To improve the resistance of rice blast,this study take BL122 which contain Pi1 and Pi2 gene as donor parent,take "Feng liangyouxiang No.1" 's male parent "Feng Xianghui No.1”(R2106)as the acceptor parent,through once hybrid,repeated backcrossing and selfing,combined molecular marker assisted selection,mainly agronomic traits investigation with identification of rice blast resistance and method,improvement of rice blast resistance of hybrid gene pyramiding and " Fengliangyouxiang No.1” two generations of one parent strain 6S with the group.Specific results are as follows:1.Pyramiding two genes in “Fengxianghui No.1”(R2106)by using SSR markers MRG4766 and AP22 which closely linked Pi1 and Pi2 gene.We get seven descendants of gene pyramiding which double gene homozygous and the main characters were similar to the parental lines.Gene pyramiding offspring and plant 6S preparation of hybrids can also detect Pi-1 and Pi-2,shows that the resistance genes have been stable inherited in the descendant of gene pyramiding.2.Identification resistance to leaf blast and panicle blast of the seven descendant of gene pyramiding and their hybrids with plants 6S.Compared with the control,the results showed that the resistance of all strains and combinations are significantly improved.The resistance of three line KP1502,KP1504 and KP1505 than "Feng Xianghui a number”in leaf blast and panicle neck blast have reached the high resistance level.With the group of the best two lines with combinations of Z2 and Z5 than " Feng liangyou No.1”leaf blast and panicle neck blast resistance respectively reached high resistance and resistance level;The resistance improved significantly compared with the control group.3.Testing plant height,growth period,ear length,effective panicles,seed setting rate,grain number per spike,1000 grain weight and yield per plant of eight main agronomic characters of "Feng Xianghui No.1" which pyramiding double gene of seven lines and their hybrid.The results showed that in addition to the individual characters have certain differences,other characters were not significant difference with the control.4.Analysis and evaluation of seven double gene pyramiding strains and their hybrid combinations with “6s” from brown rice rate,milled rice rate,length to width ratio,transparency,chalk white degree,chalk white ratio,alkali fire value,gel consistency,straight chain starch content,crude protein content of ten indexes.Besides KP1501,KP1504 and KP1507 only the remaining lines are reach grade No.2 as the same as “Fengxianghui No.1”.In combinations,besides Z1,Z4,and Z6,the rest were reached grade No.2 of high-quality rice as the same as “Fengliangyouxiang No.1”.5.After comprehensive analysis from three aspects: rice blast resistance main agronomic traits and rice quality,the result show that the KP1502,KP1505 and their hybrid combinations with “6S” which through the two resistance genes pyramiding both to maintain the control of excellent agronomic traits and grain quality,and resistance of rice blast has been significantly improved and can be inherited stably,their gronomic traits were largely restored and have high rice quality.These two materials can be promoted as an excellent hybrid rice combinations. |
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