The Study Of Inducing Wheat-thinopyrum Elongatum 3E Chromosome Translocations By Gametocidal Chromosome

Thinopyrum is a kind of perennial plant. Thinopyrum has strong regeneration, strong root, frost resistance, drought resistance and many tillers. Thinopyrum is immune to lesf rust, black stem rust, powdery mildew, stripe-mosaic disease and stinking smut, and immune to stripe rust or resistant moderately. Thinopyrum is crossed easily with wheat. E genome in diploid Thinopyrum elongatum is the fundamental genome in the polyp -loiding species of Thinopyrum. It has been found that some valuable genes for wheat breeding exist in E genome of Thinopyrum elongatum.In this study, to inducing wheat-Thinopyrum 3E chromosome translocations, hybrid, backcross and selfcross were done between Chinese spring-Thinopyrum disomic addition lines and Chinese spring-Ae.cylindryca gametocidal chromosome 2C disomic addition lines. The hybrid progeny were selected and identified by morphology, cytogenetics and molecular makers. The results are as following:1 Hybrid F₁ were obtained from two designed cross combination. F₂ were obtained from selfcross of F₁; B₁F₁ were obtained from backcross which Chinese spring-Thinopyrum disomic addition lines as male parents.2 The seedset rates of hybrid progeny were statistical estimated. The average seedset rate of F₁ selfcrossed is 31.45%, the seedset rate of B₁F₁ selfecrossed is 38.82%, it is marked compared with that of F₁ selfcrossed.3 Investigation on the spikes character of hybrid progeny plants. The gametocidal chromosome 2C induced the separation of spikes character in F₂ and B₁F₁ plants, The spikes appeared to be short-small awn, speltoid, compactoid, multi-small flowers, except for the CS similar type, 2C similar type and middle type.4 Identified salt tolerance in parents, they showed evidence of resistance compared to control CS. It proved that salt tolerance gene located in 3E.5 Sum up the number of chromosomes in progeny F₂, B₁F₁ root tip cell. The chromosome number of F₂ plants somatic cell variated from 37 to 44, mostly 42 and 44. Percentages of the plants contain 42 and 43 chromosomes were reaching to 38.89%, 22.22% respectively. The chromosome number of B₁F₁ plants somatic cell variated from 40 to 44. Mostly plants contained 42﹑43 and 44 chromosomes. Percentages of them were 35.71%﹑28.57% and 28.57% respectively. Some chromosome aberrations such as circle chromosome, telosome, dicentromeric chromosome were observed in F₂ plants.6 Observed the PMCs metaphase of F₁, F₂ plants. The chromosome configuration of F1 plants were mostly 21â…¡+2â… , equated with theoretical value. Some aberrations appeared in meiosis. A lot of plurivalents and univalents were observed in F₂ plants MI, Some abnormal phenomenon were observed in Aâ… and Aâ…¡, including chromosome fragment, chromosome bridge, and lagging chromosome.7 Detection on 3E alien chromatin in hybrids progeny by specific SCAR marker of Elytrigia. Detection on 39 F₂ plants, the frequency of the plants with E chromatin was 17.95%.8 Identification on the F₂ plants which showed positive SCAR signals by 3ES and 3EL specific primer.4 plants were positive. Specific bands were amplified in plants of 09-5-7-2,09-5-7-3,09-5-7-6,09-5-8-4 by primer Xedm96. These plants can be judged as short arm translocation preliminarily; None specific bands were amplified in any plants by primer Xedm8. So these four plants can be judged as short arm translocation or longarm deletion.