Molecular Marker-assisted Selection For Leaf Rust Resistance Gene Lr35 In 149 Wheat Cultivars (Lines)

STS (Sequence-tagged site) and SCAR ( sequence characterized amplified regions) analysis were carried out in ThLr35, FI and F2 of ThLr35, 149 wheat cultivars (lines) in China. The main results were as follows:1. The optimized STS and SCAR reaction system was established. The system had a total volume of 25 w L, containing 50ng template DNA, 1 PCR(Mg2+), 0. 2mM each dNTP, 1. 5U Tag DNA polymerase, 25ng each primer. Amplification performed in a Whatman Biometra tgradient AmpGene DNA Thermal Cycler was programmed for 3 min at 94 , 35 cycles of 1 min at 94 , 1 min for 52 -STS or for 60 -SCAR, 2 min at 72 , and a final extention at 72 for10 min after the last cycle.2. STS and SCAR analysis carried out in FI and F2 of ThLr35 showed that the 900 bp bind appeared in FI and F2 plant conferring resistance against leaf rust as well as in ThLr35, but not in the susceptible of F2. It proved the STS and SCAR markers are reliable for Lr35 detection.3. STS and SCAR analysis carried out in 149 cultivars (lines), The result showed that the 900bp bind appeared in PCR product of eight cultivars including Dongfanghong 3, Bima 1, Zaoyang, Baiyoubao, 6068, Madsen, Zhongmai 9, Xiaoyan 7631.4. In greenhouse, the 8 lines were inoculated with an avirulent race (99-8-11-5) at the second-leaf stage, and they showed resistant, except Dongfanghong 3 showing higher infection type (3) .5. The pedigree of Dongfanghong 3 is Nongda 17/xiao'e 186/Zaoyang, So Lr35 gene in Dongfanghong 3 may come from Zaoyang.The relationship of the rest 6 cultivars (lines) couldn't be identified. All of them could require the Lr35 gene from Triticum speltoides .