Construction Of Genetic Linkage Map And Detection Of QTLs For The Agronomic Traits In Barley And Gene Mapping Of Lesion Resembling Disease Mutant Bspl1

Barley is the fourth largest crop in China, and widely used in genetic research as a model plant. In this study, the RIL mapping population was derived from the cross between Golden promise and H602. Seven agronomic traits were evaluated. Correlation analyses were performed among the traits examined. The RIL population was genotyped with SSR markers, and their linkage maps were constructed with Kosambi function using software MapMaker/EXP3.0.QTLs for main agronomic traits were mapped onto the chromosomes. In this study, a lesion resembling disease mutant bspl1 is identified and studies were performed on its agronomic traits,physiological and genetic analysis. The main results are summarized as follow:1. Using the 652 SSR markers for screening polymorphism, construct a linkage map contains 119 molecular markers, 119 pairs of SSR markers can be linked respectively to the 7linkage groups, the map covered 2239.2cM with an average interval of 18.98 cM. Number of markers mapped onto linkage group varied from 10 to 28, the average of each chromosome is 17 markers.2. Golden promise and H602 with extreme difference in plant height, heading date, flag leaf length, flag leaf width, panicle length, awn length and thousand grains weight.7 traits in this RIL population are approximately normally distributed. 7 traits correlation analysis show that:heading date with plant height and panicle length showed a significant negative correlation.Plant height with panicle length, awn length, flag leaf length, flag leaf width and thousand grains weight showed a significant positive correlation. Awn height and flag leaf length also showed significant positive correlation. Leaf shape correlation analysis indicates that: flag leaf length and flag leaf width showed significant positive correlation and the coefficient is 0.552.3. There were detected 28 QTLs by using 7 agronomic traits data using QTLnetwork.Heading date has 3 QTLs, plant height has 4 QTLs, panicle length has 6 QTLs, awn length has 3QTLs, flag leaf length has 4 QTLs, flag leaf width has 5 QTLs and thousand grains weight has 3QTLs. Although there can detected QTLs in 6 chromosomes, there exist QTL hotspots, a total of4 QTL hotspots.4. Lesion resembling disease mutant bspl1, obtained from EMS mutagenesis of ZJU3. The objective of this study is to analyzed it’s physiological and genetic characteristics. The lesion appeared on leaves as red-brown spot from the beginning of seeding stage. After tillering stage the lesion no longer grows larger, and did not result in dead leav es. Moreover it did not affect plants’ spiking and fructifying. The physiogical analysis showed that mutant’s active oxygen metabolism indicated that the activity of SOD、POD and CAT in bspl1 is significantly higherthan that in wild-type plants. By comparing the differences between wild-type and bspl1 on the physiological and biochemical level, speculating that the appearance of lesion is related with the accumulation of reactive oxygen in leaves.5. Lesion resembling disease is controlled by single recessive nuclear gene: Under the field condition, F1 plants from bspl1 and other crosses showed normal green phenotype as the wild type, illustrating thar bspl1 was gorvened by a recessive gene(s). Normal and Lesion resembling disease F2 from the populations of bspl1/ZJU3 and bspl1/Morex segregated to3:1(<?20.05=3.841). This results together showed that the lesion resembling disease phenotype was controlled by a single recessive nuclear gene. Using map-based method, the single recessive mutation was located in a 1.1cM DNA region on Chromsome 2.