Molecular And Cytogeneticstudies On Derivatives Of Common Wheat-aegilops Geniculata

Wheat is one of the most important crops.A narrow genetic base of Long-term artificial selection limitedthe development of wheat breeding.Related species of wheat,which had many good traits, could be used as an excellent source of genes and distant hybridization could be the most effective way to achieve it. Aegilops geniculata Roth(2n=4x=28,UgUgMgMg) is an important tetraploid species in Aegilops L.and a useful genetic resource for wheat breeding because of the stress to lerance and disease resistance of this species. Aegilops geniculata can be easily hybridized with wheat, so it has became one of the most important species used for wheat genetic improvement. We characterized the progeny of the cross wheat cv. Chinese Spring(CS)/Ae. geniculata SY159//CS by morphological and cytogenetic identification, analysis of functional molecular markers, genomic in situ hybridization(GISH), fluorescence in situ hybridization(FISH), and disease resistance evaluation, and the results are as followings:1.Morphological and cytogenetic identification ofwheat- Ae.geniculate BC1F6 progenyThe result ofmorphology investigationon 225 wheat- Ae.geniculate BC1F6 progeny plans showed that137 plans had awns,awn ranges were 0.5~16cm;height ranges were 50 ~ 155 cm, the coefficient of variation was 20.8%; ear length range were 5 ~ 23 cm, the coefficient of variation was 28%; spikelets range were 8 ~26, the was 18.1%; tiller number rangeswere 2~78, the coefficient of variation was 64.7%.Thecoefficient of variationwas larger indicted the materials plant has a high variation margin. The cytogentic analysis result showedthe number of chromosomes in the range of 40 to 60,most materials chromosome configuration were not stable, need to be further breeding in order to gradually stabilize. The powdery mildew gene was genetic successful because majority materials were immune to powdery mildew.2. Ae.geniculate specific molecular Markers screeningWe select 600 pairs of SSR primers from 21 different chromosome of wheat to screen in order toobtain Aegilops geniculataspecific primers.As a result,39 pairs of primersamplifiedclear polymorphic bands in Aegilops geniculata SY159 but not in CS, and 31 pairs of primers amplifiedpolymorphicbands in the derivatives of common wheat-Aegilops geniculata;38 pairs of STS primers design basic on gene bankwere screened in order toobtain Aegilops geniculata specific primers, and 5 pairs of primers amplify clearpolymorphic bands in Aegilops geniculat.3. Molecular and cytogenetic identification of wheat- Ae.geniculate progeny NA0973-5-4-1-2-9-1We characterized this new line by morphological and cytogenetic identification, analysis of functional molecular markers, genomic in situ hybridization(GISH), fluorescence in situ hybridization(FISH), and disease resistance evaluation. Cytological observations suggested that NA0973-5-4-1-2-9-1contained 44 chromosomes and formed 22 bivalents at meiotic metaphase I. The GISH investigations showed that the line contained 42 wheat chromosomes and a pair of Ae. geniculata chromosomes. EST-STS multiple loci markers and PLUG(PCR-based Landmark Unique Gene) markers confirmed that the introduced Ae. geniculata chromosomes belonged to homoeologous group 7. FISH identification suggested that NA0973-5-4-1-2-9-1 was added a pair of 7Mg chromosome because it had the same signal with TA7661(CS-AEGEN DA 7Mg). After inoculation with powdery mildew(Blumeria graminis f. sp. tritici, Bgt)isolates E09, NA0973-5-4-1-2-9-1exhibited powdery mildew resistance different from TA7661, the powdery mildew resistance of NA0973-5-4-1-2-9-1 probably originated from its parent Ae. geniculata SY159.