Construction Of An Amplified Fragment Length Polymorphism Linkage Map Of Sorghum And Mapping Of Sorghum Resisitance To Sorghum Aphid Gene

Sorghum is one of the world's most important corps, ranking fifth in acreage among the cereals. It was the major food resource in African countries. It also used as feed for livestock. The sorghum aphid(melanaphis sacchari) is a key insect pest of sorghum, causing great losses to sorghum and other cereals directly and indirectly annually. It has been xonfirmed that the use of plant resistance as a pest management stategy is the most effective and economical method. It will be important theoretically and practically in the breeding processing if the Mechanism and Inheritance of the resistance to aphid were revealed and the resistant gene was further located and cloned.In this experiment to study the mechanism and inheritance of the resistance to sorghum aphid with the F1 hybrids and F2 population of the cross between QS and HN-16. A molecular genetic map for sorghum was constructed based on AFLPs (Amplified Fragment Length Polymorphism) markers using DNA samples extracted from F₂ population which derived from the cross between QS and HN-16 and to look for molecular markers linked to aphid resistance gene. The main results are as follows:1. The analysis of F₂segregation population derived from the cross between HN-16 and Qsshowed that the segregation tatio was corresponding with 3:1, the aphid resistance of sorghum is a quality trait. The resistance to aphid was controlled by a dominant major gene.2. A molecular genetic map for sorghum was constructed based on AFLPs (Amplified Fragment Length Polymorphism) markers using DNA samples extracted from 100 F₂ population which derived from the cross between QS and HN-16. The highly dense linkage map constructed by using Mapmaker3.0 software analysis which consisted of 12 linkage groups, a total of 93 newly screened markers and covered 686cM of sorghum genome, with the average interval of 7.38 cM.3. BSA population in order to look for markers linked with sorghum resistance to aphid had been found that three markers are E61/M59-320and E63/M52-45. They were identified on chromosome 2, with the estimated genetic distance of 9cMand 11 cM.