Studies On Genetic Characters Of Several Interspecific Hybrids F₁ In Elymus And Construction Of Molecular Genetic Map Of Weatgrass

Elymus and Agropyron are perennials in Triticeae of Gramineae, they have characteristics of wide adaptability, strong resistance, high yield and good quality, which are important genetic resources to improve grasses and wheat crop varieties. The most species of the two genera are both excellent cultivated forage grasses and soil and water conservation grasses. The hybrids F₁ between Elymus sibiricus and Elymus purpuraristatus, between E. canadensis and E. escelsus and between Agropyron mongolicum and A. cristatum cv. Fairway were successively got to create new germplasm (new varieties) with excellent characteristics of parents, and F₂ population of A. mongolicum×A. cristatum cv. Fairway hybrid F₁ was got through self pollination with bags. The growth, development and molecular cytogenetics of E.sibiricus×E.purpuraristatus hybrid F₁, E. purpuraristatus×E. sibiricus hybrid F₁ and E. canadensis×E. escelsus hybrid F₁ were studied, and wheatgrass grass molecular genetic map was constructed based on AFLP, RAPD markers, at the same time, QTLs of ten important agronomic traits, such as height, number of tillers, plant fresh weight et al, were conducted. The main results are as follows:1. Growth rate of E. sibiricus×E. purpuraristatus hybrid F₁ was significantly more than its parents, growth rate of E. purpuraristatus×E. sibiricus hybrid F₁ was in the middle of their parents; the height of E. sibiricus×E. purpuraristatus hybrid F₁ was 143.2 cm, the height of E. purpuraristatus×E. sibiricus hybrid F₁ was 129.7 cm, the ear forms of hybrids F₁ was in the middle of their parents, pollens were highly sterile; hybrids F₁ both E. sibiricus×E. purpuraristatus and E. purpuraristatus×E. sibiricus were pentaploid (2n = 5x = 35), chromosome configuration of E. sibiricus×E. purpuraristatus hybrid F₁ was 6.90â… +14.02â…¡, chromosome configuration of E. purpuraristatus×E. sibiricus hybrid F₁ was 7.82â… +13.59â…¡, the important reasons why hybrid F₁ is sterile is that chromosome pairing behavior is irregular. There were significant differences in EST ezymograms among parents of E. sibiricus, E. purpuraristatus and hybrids F₁ at tillering stage, which is an important basis for the identification of hybrids in protein level.2. The growth vigor of hybrid F₁ between E. canadensis and E. escelsus was strong, the growth rate was significantly more than its parents, with an average height 146.07 cm; F₁ plant form tended to his maternal E. canadensis , the ear forms of hybrids F₁ was in the middle of their parents, hybrid F₁ was completely sterile; chromosome number was 35 (2 n = 5x = 35), average chromosome pairing configuration at PMCMâ… was 5.79â… +14.31â…¡+0.17â…¢, chromosome synapsis was loose, and that univalent and multivalent frequency was high is the reasons why hybrid F₁ is sterile. 16 primers for RAPD amplification to fit E. canadesisa×E. escelsus F₁ and their parents were screened, total 215 loci was amplified, polymorphic loci accounted for 72.1%; the genetic distance between parent E. canadesis and E. escelsus was 0.7122, the genetic distance between hybrids F₁ and E. canadesis was 0.6643, while the genetic distance between hybrids F₁ and E. escelsus was 0.2329, hybrid F₁ tended toward parternal. Young ear explant tissue culture regeneration system for E. canadensis×E. escelsus F₁ was established, the optimal callus induction medium was MS +2.0 mg / L 2,4-D, optimal medium for seedlings differentiation was MS +2.0 mg / L 6BA + 0.4mg / L NAA, the optimal rooting medium was MS +0.5 mg / L IBA. The establishment of regeneration system provide a necessary conditions for the colchicine-induced F₁ hybrid callus chromosome doubling.3. Polymorphism of Agropyron mongolicum and A.cristatum.cv..Fairway was detected, 16 pairs of appropriate AFLP primers were screened, RAPD appropriate primers 19, 248 polymorphic loci were amplified in population F₂ with these primers, AFLP polymorphic loci was 211, RAPD polymorphic loci was 37. The AFLP, RAPD markers separation analysis of population F₂ found that the separation ratio of the tag-loci from two parents was close to 1:1, under the conditions of P <0.05, 49 markers in 248 markers Deviated the Mendel separation ratio 3:1, accounted for 19.8% of total number of tagged loci, which showed that the population F₂ is suitable for genetic mapping.4. Molecular genetic map of wheatgrass was constructed for the first time with separated population F₂ of hybrid F₁ between A. mongolicum and A. cristatum.cv..Fairway, which includes seven linkage groups, 176 molecular markers, 161 AFLP markers, 26 RAPD markers, total length of map was 416 cM, the average map distance was 2.47 cM. 5. 13 QTLs for10 important agronomic traits of diploid wheatgrass were detected, the additive effect varied, the genetic contribution rate of each locus was between 10.1% and 34.3%, 13 QTLs was distributed in the 6 linkage groups,one QTLs for height, one QTLs for leaf length, one QTLs for individual fresh weight, one QTLs for individual dry weight, one QTLs for leaf width , one QTLs for tiller , two QTLs for stem diameter, two QTLs for ratio of stem to leaves, two QTLs for of leaves number, one QTLs for ear length.