Molecular Cytological Identification Of Stable Addition(Substitution) Lines Of Wheat And Thinopyrum.intermedium Hybrids

Wheat(Triticum aestivum L.)is one of the main food crops of mankind,and its yield and quality directly affect human production and life.However,in the cultivation and breeding work,wheat is affected by various factors such as cultivation environment,soil fertility,pests and diseases,and its narrowly genetic basis.Therefore,broadening the genetic basis of wheat is the basis and prerequisite for further breeding improvement.There are many wild relative species of wheat,and these wild relatives contain a large number of favorable mutations that can be used in wheat improvement.By the method of distant hybridization,many excellent genes of the wild relatives of wheat can be introduced into the wheat background,and can be used as an intermediate material for the improvement of wheat.Thinopyrum intermedium is one of the wild relatives of wheat,and many of the excellent genes have been used for wheat breeding improvement through distant hybridization.In this study,four stable wheat-Th.intermedium hybrid lines:addition line 15-471(hereinafter referred to as 15-471),addition line 18-157(hereinafter referred to as 18-157),substitution line 18w-51(hereinafter referred to as 18w-51)and substitution line 18w-52(hereinafter referred to as 18w-52)were subjected through genomic in situ hybridization(GISH),fluorescence in situ hybridization(FISH)and PLUG molecular marker identification,the main results are as follows:1.Agronomic traits observations showed that 15-471 was resistant to stripe rust,and its effective tiller number,spikelet number,kernel number and thousand seed weight were significantly better than its wheat parent Chuanmai 107.Double spikelets grew in the middle and lower part of the ear and the seeds are more full than Chuanmai 107.Cytological identification showed that the chromosome configuration of 15-471 was2n=44=22II,indicating that 15-471 is a stable material.GISH and FISH analysis showed that 15-471 contains a pair of Th.intermedium St chromosomes and a pair of 1RS.1BL translocation chromosomes.Identification of the PLUG molecular marker revealed that the additional Th.intermedium chromosomes in 15-471 were located in the third homologous group.Therefore,15-471 is a wheat-Th.intermedium 3St addition line.2.The seeds of 18-157 are also slender,distinct from its wheat parent,but similar to octoploid buckwheat.The number of chromosomes is 2n=44.GISH and FISH analysis showed that 18-157 were added a pair of Th.intermedium chromosomes,and the pair of chromosomes was a pair of St-J~S translocation chromosomes.The results of PLUG molecular marker analysis showed that the pair of translocation chromosomes was located in the second homologous group of wheat.Therefore,18-157 is a wheat-Th.intermedium2St-2J~S addition line.3.18w-51 was infected with stripe rust and powdery mildew,and its grain traits were similar to those of its wheat parents Cuanmai 107.The number of chromosomes is 2n=42.GISH and FISH analysis showed that the pair of 4D chromosomes of wheat was substituted with one pair of St chromosomes of Th.intermedium.The identification results of PLUG molecular markers showed that the pair of Th.intermedium chromosomes belonged to 4th homologous group of wheat.Thus,18w-51 is a wheat-Th.intermedium4St(4D)substitution line.4.18w-52 was also infected with powdery mildew and stripe rust,with thinner and longer grains and relatively low 1000-grain weight.The number of chromosomes is 2n=42.The GISH analysis using the genomic DNA of Ps.spicata as the probe combined with FISH analysis showed that the 2D and 4D chromosomes of the wheat in 18w-52 were substituted with a pair of St.J~S translocation chromosomes and a pair of J chromosomes of Th.intermedium,respectively.The PLUG molecular marker showed that the St.J~S translocation chromosome of Th.intermedium belongs to 2th homologous group of wheat,and the J chromosome belongs to the 4th homologous group.Therefore,18w-52 is a double-disomic wheat-Th.intermedium 2St.2J~S(2D).4J(4D)substitution line.In summary,the excellent genes contained in these four wheat-Th.intermedium hybrid progeny stable lines can contribute to the improved breeding of wheat.