Dissertation > Agricultural Sciences > Crop > Economic crops > Oil crops > Rapeseed ( Brassica )

Improved Spring Rapeseed Heterosis Through Introgression of the Semi-winter Rapeseed Genetic Material (B.napus)

Author LiuHaiDong
Tutor DuDeZhi
School Qinghai University
Course Crop Genetics and Breeding
Keywords New spring Brassica napus Genetic composition Geneticdiversity Heterosis
CLC S565.4
Type Master's thesis
Year 2012
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This study included2weak-winter rapeseed parents (Brassica napus L.),2spring restorer Brassica napus L.lines parents,2spring male sterile Brassica napusL.lines and16new spring restorer Brassica napus lines that hybrided by2springrestorer lines parents and2weak-winter rapeseed parents.To study the geneticrelationship of those materials,compared with genetic differences between the newlines and corresponding parental restorer lines and two spring male sterile lines bySSR, SRAP, AFLP molecular markers.After importing semi-winter geneticelements,compared with the difference between (spring CMS×new spring restorerlines)F1and (spring CMS×spring restorer) F1’ of heterosis,hybrid performance andresistance to Sclerotinia disease,proved the semi-winter rapeseed Brassica napusL.improve spring Brassica napus rapeseed heterosis was effective.The main resultsare as follows:1. Cluster analysis based on three molecular markers that all the materials canbe grouped into4classes when the similarity coefficient was0.583,2spring restorerlines parents Ag-5、Qu and2spring male sterile lines contains3253-3264and tent100were grouped into class I.8new spring restorer lines were grouped into classⅡ.Weak-winter rapeseed parent LB and5new spring restorer Brassica napus lineswere grouped into class Ⅲ, Class Ⅳ contained weak-winter rapeseed parent305and3others new spring restorer lines. Genetic distance between the new restorer lines931-935among16new restorer lines and two male sterile lines are less than thatgenetic distance between their restorer parental Ag-5and two male sterile lines,Genetic distanctent between tent23and Sterile Ⅰis less than that genetic distancebetween its restorer parental Ag-5and Sterile Ⅰ,while the genetic distance between14new restorer lines and the two male sterile lines is greater than the geneticdistance of corresponding parents and two spring sterile restorer lines.Thesemi-winter parent band ratio in spring restore lines and between spring sterile linesand restorer lines of genetic distance was significant positive correlation, the correlation coefficient is0.55; the spring restore lines of semi-winter parent bandratio and between spring CMS II and spring restoration of genetic distance wassignificant positive correlation, the correlation coefficient is0.73,which showed thatthe insertion of semi-winter varieties’genetic compound into spring restore lines caneffectively expand the genetic difference between restorer lines and CMS lines.2.12new hybrid breeding of restorer lines that hybrided by parental restorerline Ag-5and weak-winter varieties305and LB, hybrid among sterile line1(SI)andthe new restorer lines and the combination of S I×Ag-5, there were9combinationsthat SI corresponding maintainer yield as high value parent.The heterosis (HPH)analysis results showed, the yield heterosis of SI×zhang23hybrids was no morethan SI×Ag-5heterosis, the remaining7combinations were over S I×Ag-5heterosisand distribution were-1.78%-46.25%. The main reason is due to the expansion ofgenetic distance in the spring restorer lines though introgression into weak-wintergenetic component. With CMS II (SII),there were11New Restorer Lines geneticdistance expansion with SII and there were6combinations among thosecombinations and SII×Ag-5that SII corresponding maintainer yield as high valueparent, which analysis showed that, there were4combinations between new restorerlines and S II the heterosis of F1’sYP strong were more stronger than SII×Ag-5yieldheterosis,distribution were25.56%-63.63%.Insertion into the semi-winter geneticcomponent in the spring of parental restorer lines,which can effectively improve thespring Brassica napus rapeseed heterosis.3.The YP of26combinations results showed that,The YP of all combinationsamong the combination between12New Restorer Lines and SI were more thanSI×Ag-5except the combination SI×zhang23.There were7hybrids’YP of thecombinations between12New restorer lines and SII were more than SII×Ag-5.There were2combinations S I×bu7-9and SII×4-6hybrid yield per plant weresignificantly higher than the parent restorer lines and two sterile lines forcombination (P <0.05)., It can effectively improve the yield of hybrids throughinsertion into the semi-winter genetic component in the spring of parental restorerlines.Further to analysis the correlation that the YP and mid-parent value and highvalue parent indicated that, the YP and yield per plant of two parents value correlation were not showing significant level, when parental genetic distance wereover0.400(It consisted of22combinations at this condition), hybrid yield per plantand two parents value correlation coefficient was0.44, it was significant level. Itshowed that when parental genetic distance bigger, if two parents had high yield,while hybrids also showed high yield.4. Different hybridization patterns derived from F1to Sclerotinia diseaseanalysis results showed, different crossing model of F1disease resistance hadsignificant difference, three hybrid mode generations of resistance Sclerotiniadisease by strong to the weak was Spring×(Spring×Weak-winter)>Spring×Weak-winter> Spring×Spring.

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