Dissertation
Dissertation > Agricultural Sciences > Crop > Cereal crops > Wheat > Wheat

Allocation and Molecular Markers of a Powdery Mildew Resistance Locus to the Chromosome 6R of Secale Cereale L. CV. ’Jingzhouheimai’

Author WangDan
Tutor ZuoZengJun
School Nanjing Agricultural College
Course Genetics
Keywords Secale cereale Triticum aestivum Blumeria graminis Alien chromosome addition lines Molecular markers FISH
CLC S512.1
Type Master's thesis
Year 2010
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Chinese rye, Secale cereale L. cv. Jingzhouheimai confers resistance to several important wheat diseases, making it a useful resource for wheat improvement. An allooctoploid (2n=8x=56;AABBDDRR) was derived following hybridization of Jingzhouheimai with hexaploid wheat landrace Huixianhong and doubling of the F1 chromosome number. A set of addition lines except 6R were developed by backcrossing the primary amphiploid to the wheat parent, and a powdery mildew resistance gene PmJZHM2RL was mapped on chromosome 2RL. However, the current additions are imcomplete. Thus, development of wheat-Jingzhouheimai chromosome 6R alien lines is very necessary. In this study, molecular markers specific for rye chromosome 6R were identified and used for marker assisted selection of 6R additions. Powdery mildew test further allocated a resistance locus to the chromosome 6RL of rye cv. Jingzhouheimai.In this paper,113 markers specific for the seven rye chromosomes were identified, in which 3 markers{Xscm78, Xscm176 and Xscm304) previously mapped on rye chromosome 6R, could be used as candidate markers of Jingzhouheimai chromosome 6R. The 24 chromosome specific markers were then used for marker aided selection of chromosome 6R addition lines in 297 F1-F3 plants of Jinghui 1/Huixianhong, some of them were confirmed by GISH and FISH. This allowed for the identification of seven disomic 6R addition plants, twenty monosomic 6R addition plants, five mono-telosomic 6RS addition plant, eight mono-telosomic and one ditelosomic 6RL addition plants.937 PCR-based markers derived from wheat, rye, barley Brachypodium were then screened and 22 were specific for chromosome 6R, according to the amplification pattern in MtA6RL and MtA6RS,22 6R specific markers were allocated to different arms of 6R, with seven on 6RS and 15 on 6RL. Alignment of the sequence to rice and brachypodium genome revealed rye chromosome 6R was colinear to R2 and Bd3.In 114 MA6R and MtA6RL selfing progenies,6 additions with the 6RL were highly resistant to powdery mildew, while 5 additions with 6RS and 72 without 6R chromosome were sensitive, indicating that the powdery mildew resistance locus could be allocated on the long arm of 6R. The 6RL markers could be used for monitoring the resistance gene introgression into wheat.

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