Insect Resistance To Be Authenticated And Genetic Analysis Of Trans-Bt Gene Maize

To investigate the expression,yield heterosis and combining ability of the trans-Bt gene corn materials,this paper had used the Reid group elite line PH6 WC,the inbred lines J1490,J1495 and 4DH-10,as well as the extrinsic line PH1 CPS as the female parents,while the Non-Reid-based trans-Bt gene materials 6DH-85,J1401,6DH222,8DH273 and 8DH279,as well as the inbred lines J9D207,J1628 and J1668 as the male parents,to generate(5×8)40 cross combinations according to the NCII design,so as to investigate the insect resistance,yield heterosis and combining ability of the trans-Bt gene materials at the densities of 60000 plants/hectare,70000 plants/hectare and 80000 plants/hectare.The following results could be oBtained.1.Molecular detection results suggested that,J1401,8DH273 and 8DH279 were positive in the 5 transgenic materials,which indicated that exogenous genes might be eliminated or silenced after several generations of sexual propagation during the process of breeding the transgenic insect-resistant plants,thus affecting their application value.Trans-Bt gene detection results based on the crossbreeds generated from J1401,8DH273 and 8DH279 revealed that,11 out of the 15 cross combinations in 2017 were positive,while all the 15 cross combinations re-generated in 2018 were all positive,which suggested that the exogenous genes might be silenced in some combinations.Therefore,transgenic detection should be carried out when breeding the transgenic insect-resistant plants.2.Insect-resistant identification results demonstrated that,the trans-Bt gene offspring materials had high field and indoor insect resistance performance against armyworn at seedling stage and corn borer at soft dough stage,which suggested that the trans-Bt gene materials oBtained through backcrossing had displayed insect resistance at each stage corn growth.3.The heterosis results revealed that,the transgenic cross combinations PH6WC×8DH273 and PH6WC×8DH279 had the best performance among the 40 combinations with regard to the average heterosis under three densities;meanwhile,the transgenic cross combinations PH6WC×8DH279,J1490×8DH279 and PH6WC×8DH273 had the best performance in control heterosis,which indicated that the combinations with the highest heterosis were the highly insect resistant combinations.At the same times,such results also demonstrated that the hybrids with strong heterosis and insect resistance had integrated multiple favorable properties of high yield,high quality and high insect resistance,which had exhibited great commercial value.4.Combining ability results suggested that,parents 8DH279 and 8DH273 had the best performance in terms of plot yield general combining ability at three densities,but the trans-Bt gene parent J1401 had low general combining ability.Moreover,parents 8DH279 and 8DH273 could generate the most combinations with positive effect value of yield specific combining ability,indicating that the trans-Bt gene materials 8DH279 and 8DH273 had high yield potentials.5.The yield of the transgenic Bt gene combinations J1490×J1401,J1495×J1401,PH1CPS×J1401 and 4DH-10×J1401 was better than that of the control at 60000 density.It was suggested that the yield increase of the transgenic Bt gene was due to the resistance effect of the transgenic Bt gene to insect pests.