Study On Construction Of A Genetic Linkage Map Of Jute Using SRAP Markers

Jute(Corohorus olitorius L)is a nature fiber crop and plays a very important position in people′s livelihood. However, in the construction of genetic linkage map and the use of molecular marker-assisted breeding, it drops behind the other major crops. By now, there is no relative report on genetic linkage map of jute. In this study, SRAP markers were applied to construct the first jute genetic linkage map in country, which laid a solid foundation for the theory of agricultural traits of gene mapping, QTL analysis, molecular marker-assisted breeding. The major results as below:(1) The 187 F2 individuals are from the cross of two jute, glyc-anesthesia (wild species) and wide leaf jute (cultivated species).(2) Take glyc-anesthesia (wild species) and wide leaf jute (cultivated species) as template, 56 pairs of SRAP primer combinations with good polymorphism were selected from 19X27 forward and reverse of the SRAP primer combinations.(3) Using the screened 56 pairs of SRAP primer combinations, PCR was applied on the F2 population. 155 polymorphic bands were generated in the F2 population analysis. The average of polymorphic bands produced by one primer pair was 2.8, and the maximum was 6.(4) Using mapmaker/exp 3.0, a linkage map was constructed, which consisted of 125 SRAP markers distributed in ten linkage groups (L0D≥3 0). Each SRAP primer pair could generate 8~20 clear bands with a length range between 100 and 2000 bp.While each linkage group have 2~38 markers, 2231.9cM in total. The average map distance is 17.86cM, with the maximum map distance is 36.6cM and the minimum map distance is 4.5cM. The markers are well-distributed with aggregation in each linkage group.(5) Position of qualitative traint:There were 3 morphological markers in the map.They were the colour of stipule,the colour of stipe and the colour of leaf margin. They were located in the linkage group 1.The colour of stipule linkaged with M18E7 and M12E18. The genetic distance between them are 11.2cM and 12 cM. The colour of stipe linkaged with M17E10 and the colour of leaf margin.The genetic distance are 21.1cM and 4.5cM.The colour of leaf margin linkaged with M12E9-1 and the genetic distance is 20.9cM.(6) Among these 155 markers,37 markers (23.9%) segregated unconventionally against the expected 3:1 ratio.28 (75.7%) with the type of male parent, and the other 9 (24.3%) preferred the type of female parent, which could be caused by selectivity of gametes. Although jute has 7 pairs of chromosomes,we constructed ten linkage groups, which close to the chromosome number. In this study,the average map distance is too large, which requires to be further deepened for building a genetic linkage map of Jute with evenly-distributed markers and high-density sites.