Analysis Of Physiological Characteristics Of Sorghum Germplasm Resistance To Race 4 Of Head Smut And SRAP Marker

Head Smut is one of the most important Sorghum diseases around the world.This disease can damage the structure of sorghum panicle,resulting in seriously reduced grain production or even no harvest.For breeding new varieties resistant to head smut,screening molecular markers associated to resistance gene in sorghum,and achieving the real molecular marker-assisted breeding,a sensitive sorghum variety Sanchisan,and a resistant variety 961541 were selected as research materials the differences of field characters and physiological indicators were analysed,using the SRAP markers related to Head Smut resistance were screened by bulked segregation analysis（BSA）method using the F₂ population.The results showed that:1.Differences of field traits were analyzed by morphological markers,the following results were observed: Sanchisan exhibited better morphological parameters than 961541 in the field traits,particularly in terms of plant height,stem diameter,stem height,ground stem section number of ears,ear length,ear coarse,primary branch number,fringe,spike grain weight,number of spikelets and the grain yield.The grain colors were also different,the grain colors of Sanchisan and 961541 strains were yellow and white2.The differences of defense enzymes in resistance plant and sensitive plant were studied in four times（seedling stage,jointing stage,heading stage,mature stage）of sorghum,the results showed that the physiological indicators had bigger difference between resistance plant and sensitive plant in jointing stage and heading stage;at the heading stage,the catalase（CAT）activity,peroxidase（POD）activity,superoxide dismutase（SOD）activity of resistance plants were significantly higher than that of the sensitive plants,the malondialdehyde（MDA）content in resistance plants were lower than that in sensitive plants.3.To build F₂ populations,the material 961541 as a female,which is immune to physiological races 1,2,3,and 4,was crossed with Sanchisan which is sensitive,the F₂ group was screened by bulked segregation analysis（BSA）and the related sequence amplification polymorphisms（SRAP）.Results show that: the incidence of sensitive parent Sanchisan is 37.5%,the incidence of resistance of 961541 parents of 0%,the incidence of F₁ generation was 0%;the F₂ populationhad a total of 211 plants,of which 16 were sensitive and 195 were resistant,with an incidence of 7.58%.the incidence of F₂ close to 15:1,it was speculated that resistancegenes to head smut race 4 should be controlled by 2 non-allelic genes.;Among289 pairs SRAP primers,119 primers showed differences in parents,9 pairs primers showed differences between resistant pool and sensitive pool.the banding pattern of resistance pool was the same as 961541,and the sensitive pool was as the material Sanchisan,Finally,only one pair primer Em4/Me6 from SRAP showed differences in resistant plant and sensitive plant.