Heterosis,Combining Ability And Correlation Analyses Of Stalk Strength Related Traits In Brassica Napus L.

Rapeseed lodging resistance breeding is highly concerned,but reports related to this period is now so lacked.However,the stalks mechanical strength of the stem is very important to the breeding selection.Rapeseed is one of the most widely researched or used crops in heterosis,To choose the best hybridized combination which could be widely used in production,people should pay more attention to the parent combination.Therefore,it is necessary to do such kind of research related to t the hereditary characters of stem strength.The materials of this research are 10 inbred line of Brassica napus L.With different stalk Strengths from SiChuan Agricultural University.According to the Griffing diallel cross method 2,these ten cabbage type rape will be made into 55 Diallel cross combinations(10 parent selfing groups and 45 orthogonality groups.)All these materials will be analyzed from different traits related to stalk strength(including stem diameter?thickness?puncture strength?bucking strength?cellulose content?Lignin content)in different growing period——initial flowering?final flowering stage and mature period.The experiment will choose random combinations to investigate 6 traits related to stalk strength intensity among these materials,and then we will analyze the variance?hybridization advantage?combining and inheritance.Important results of this experiment:1.The result of analyzing stalks strength of different parts of their growth stages:the stem diameter correlation coefficient is higher during the initial flowering and mature period.(r=0.96**).In these two periods,the correlation coefficient of puncture strength is also higher than other period(r=0.90**).The stem strength related traits has much correlation during initial flowering?final flowering stage?mature period.If needs to measure,you can choose any period between initial flowering?final flowering stage and mature period.2.stem strength related traits' analysis shows:the thickness and puncture strength is positive correlation(r=0.47**?r=0.39**).pucture strength and bucking strength is highly positive correlation(r=0.6**).But other stem strength traits has little relation.Another analysis between stem strengthrelated traits and agronomic and economic shows:the puncture strength has positive correlation with height?effective branches?length of main inflorescence?yield per plant.However,puncture strength has highly negative correlation with the secondary branch number.(r=-0.35**).Then stem strength related traits has less highly correlation with the longest branches?the pod length?seed number per pod and weight.3.The advantages on heterosis of traits related to stalk strength shows:45 cross combinations,stem diameter,puncture strength and flexural strength in six main raits related to stalk strength have certain advantages,the transgressive advantage is more obvious,the advantage of the cellulose content and lignin content is negative.In addition to the content of cellulose and lignin content is negative advantages,other traits showed strong positive heterosis.4.The combining ability of the traits related to stalk strength show that:GCA variances of stem diameter,thickness,puncture strength,flexural strength,cellulose and lignin content reached extremely significant level in addition to thickness,the SCA variance only stem diameter,cellulose content and lignin content reached very significant level;MH101-7 out of 10 parents,SN3-2,628-5 stem strength related character has four larger properties of GCA,there is a big positive effect,but a poor performance in a certain character,there are negative effects;MC0411 and N63-1 have four traits related to stalk strength of GCA is small,there is negative effect,but at a certain trait of GCA is larger,there is a big positive effect.5.Considering GCA effect of the stem strength related traits,in selected 10 parents,NMH101-7,SN3-2,628-5 are the inbred lines of the ideal,stems from the combination of screening to high strength composite possibility is big,so they should be made full use.6.For various characters of genetic parameter estimates show that the size of the narrow sense heritability of points puncture strength>flexural strength>lignin content>stem diameter>cellulose content.All narrow sense heritability of traits are less than 50%.Puncture strength,flexural strength,lignin content,these traits like thick stems,cellulose content are selected in the later generations.