Development And Identification Of Wheat-rye Alien Chromosome Lines And Triticale Variants

Wheat is one of the most important food crops in the world.Breeding and utilization of new varieties is an important guarantee for high and stable yield of wheat.However,due to strict artificial selection and the utilization of a few founder parents in breeding,the genetic basis is narrowing,thus leading to be lack of durable disease resistance and wide adaptability,which limits the further improvement of yield,and even causes the epidemic of diseases in wheat.Rye is an important gene resource for wheat improvement.The wheat-rye translocation line T1RS·1BL has been widely used in wheat production in the world and is a founder germplasm for wheat improvement.However,as T1RS·1BL was only derived from German rye Petkus,and its type was single,long-term and large-scale utilization of this translocation became an important manifestation of genetic narrowing.Moreover,with the evolution of physiological races of pathogens,the resistance genes carried by T1RS·1BL have been gradually defeated.Therefore,it has important application potential to continue to explore and utilize more favorable alleles of rye.The previous results of Nanjing Agricultural University showed that there were abundant chromosome polymorphisms in cultivated rye varieties,but the effect on these polymorphic chromosomes was not clear.In this study,wheat-rye alien chromosome lines and triticale variants with obvious polymorphisms were selected and identified either by hybridization between wheat and rye or between different ploidy triticale lines,which provides new genetic resources for the improvement of wheat and triticale.The major results are as follows:Chromosomal composition of wheat Huixianhong,Jingzhouheimai,octoploid triticale Jinghui1 and hexaploid triticale WOH1084 have been analyzed by genomic in situ hybridization（GISH）and sequential fluorescence in situ hybridization（FISH）,All chromosomes of wheat and rye can be clearly identified by ONPM#5.Combined with sequential FISH with ONPM#4-3,consistent karyotypes of two oligonucleotide probe multiplexes were developed which provides a simple and efficient tool for identifying wheat-rye alien chromosome lines and triticale variants.Based on ONPM#5 FISH,a total of 114 plants with 16 types of the wheat-rye alien chromosome lines of Huixianhong and Jingzhouheimai have been identified,which included 24 plants of DS2R（2B）,18 plants of DS1R（1D）/DS2R（2B）,14 plants of MS2R（2B）,13 plants of DS1R（1B）/DS2R（2B）,12 plants of T1RS·1BL,7 plants of DA2R,6 plants of RT6BS·2DS/6BL·2DL,4 plants of Mi A2RS,4 plants of Dt A2RS,3 plants of MS1R（1D）/Mt A1RS,each 2 plants of DS2R（2A）,MA2R and MS2R（2B）/Mt A2RS,and each 1 plant of MA2R/Mt A2RL,MS2R（2B）/Mt S2RS（2B）,MS2R（2A）/Mi S2RS（2A）and MA2R/Mt A2RS.To identify more wheat-rye aline chromosome lines,41 plants of Huixianhong×Jingzhouheimai hybrids F₂were analyzed.The results showed that their chromosome number varied from 39 to 49.Total 18 types of polymorphisms in R genome were identified where the most polymorphisms were 1R（4 types）and 6R（4 types）,while the others were 4R（3）=5R（3）>7R（2）>2R（1）=3R（1）.39 of 41 plants were resistant to powdery mildew and 7 plants produced 32 seeds after selfing.In order to induce chromosome recombinations of different rye,crosses between WOH1084 and Jinghui1 was made.A total of 561 F₉plants derived from 100 plants of F₈were identified.27 F₉lines（27/100）had stable chromosomes,while the other 73 lines（73/100）were unstable.Among 561 plants,except DS6D（6A）found in WOH1084,323 other variations were founded,including 222 numerical variations,23 structural variations and 78complex variations.Among ABDR genomes,R genome chromosomes had the most recombination types（21 polymorphic types）,followed by A genome（12）,B genome（12）and D genome（9）.Of 54 polymorphic types,39 were parent types,and the other 12 were recombination ones.Chromosome 1R had the most recombination types,which indicated that hybridization of different ploidy triticales could be an effective way to rye chromosome recombination.In order to accelerate the induction of chromosomal variations in triticale,the F₆hybrid seeds of WOH1084 and Jinghui1 were irradiated with ionizing radiation.A total of 327 M₃plants derived from 73 M₂plants were identified.In addition to DS6D（6A）from parent WOH1084,262 other variations were identified which included 34 structural variations,168 numerical variations and 60 complex variations.Based on the two methods used above,five homozygous double disomic substitution lines involving D genome（except 3D and 5D）were developed,which included DS6D（6A）/DS1D（1B）,DS6D（6A）/DS2D（2B）,DS6D（6A）/DS4D（4B）,DS6D（6A）/DS6D（6B）and DS6D（6A）/DS7D（7B）,a set of monosomic lines（M1R～M7R）,trisomic lines（Tri1R～Tri7R）of rye and 12 monosomics lines（except 6A and 5B）of wheat in hexaploid triticale background,which provides new germplasms for gene mapping,gene interaction researches and genetic improvement of both wheat and triticale.