Exploration On The Imorovement Potential Of Omportant Characters Of Hexaploid Triticale

Hexaploid triticale,a new gramineous plant created in the modern era,has the characteristics of large biomass and good resistance to stresses,and is suitable for planting in the areas of agriculture and animal husbandry.However,in China,the current improvement of triticale is relatively weak.And the study on triticale seedling traits hasn't been enough.In order to clarify the improving potential for the important traits of triticale,provide the basis for cross breeding of grain and forage triticale,and confirm where the QTLs controlling triticale seedling are.This research was divided into three aspects.The winter triticale"Lanxiaohei",two spring triticale line of CIMMYT,"CM-12"and"CM-13",and their three F₁ and F₂ hybrid populations were used as materials to investigate their important agronomic traits in field,such as seedling phase,plant height,number of panicle per plant,spike length,number of spikelets,leaf traits and stalk characteristics.The combining ability of each trait was analyzed,then the genetic variation coefficient and heritability of each trait of three F₂ populations were calculated to explore the improving potential.The principal component analysis,with characteristic that can intuitively analyze the complex traits,was used to analyse 14 agronomic traits in CM-12/Lanxiaohe F₂ hybrid population.The 14 complex characters were overall grasped,thus can be used to analyze the relationship among the characters more effectively.The seedling phase can directly describe the winterness and springnessthe of triticale,therefore,BSA method was used to construct pools based on triticale seedling traits.Then SNP660K chip and 40 pairs of SSR primers was used for QTL mapping.The result was showed as follows:1 The hybrid population of winter and spring triticale had higher coefficient of variation and heritability than that of spring and spring triticale.The heritability of triticale traits,including stem length,flag leaf width and flag leaf length,was higher,so was the genetic variation coefficient.For CM-12/LXH,the heritability of ear length reached 0.9245,the flag leaf width reached 0.8196,variation coefficient was higher.It was of great potential and feasible to select these important traits using segregation populations.2 The coefficient of variation of 9 traits was listed as:Spike number per plant>Neck length of spike>Length of flag leaf>Second node from the top>Flag-leaf width>Node length below ear>Length of Spike>Number of spikelets>Plant height.The heritability of 9traits was listed as:Neck length of spike>Length of Spike>Flag-leaf width>Plant height>Second node from the top>Node length below ear>Length of flag leaf>Number of spikelet>Spike number per plant.3 The 14 agronomic traits can be divided into 5 principal components by principal component analysis.It can explain 70.612%of the original character.Among 5 principal components,the largest contribution rate was originated from the first principal component,biomass components.The highest contribution rate to biomass components was plant height,up to 0.836.4 Analysis of SNP660K chip showed that a total of 130 chip loci were more concentrated on the 3A chromosome including 13000000-16000000bpand 682000000-683000000kb.We can determine initially that the loci controlling seedling upright and seeding creeping was located on the 3A chromosome.Screening of SSR markers was conducted using 328 pairs of SSR markers on chromosome 3A.All the markers was preserved in our laboratory.40 pairs of SSR markers which showed differences between the parents were obtained to map F₂population of 150 materials.2 QTLs were detected,located between wmc749 and wmc26,and between wmc527 and wmc474,respectively.The corresponding LOD values were 7.74 and2.94,accounting for 11.2 and 4.3,respectively.The main QTL derived from the parent Lanxiaohei,the dominant effect was 0.85.