| Amplification and improvement of germplasm resources are important ways to solve the problems of narrow germplasm resources,homogenization of germplasm resources and close genetic relationship among varieties.Introduction of foreign germplasm resources and improvement of foreign germplasm resources are effective methods for amplification of germplasm resources.In this study,four improved lines(J9D207,J1866,J1518,J1608)were developed by two rounds of genetic improvement using DH breeding technology based on the backbone inbred lines of Non-Reid group.There four improved lines and two basic lines were used as male parent,five Reid group backbone inbred lines were used as female parent,and 30 crosses were made.In this study,the genetic similarity of two basic lines and four improved lines was analyzed by SSR molecular marker technology,and then the genetic gain,heterosis,combining ability and correlation analysis of the improved lines were studied.The results are as follows:1.The genetic similarity analysis of two basic lines and four improved lines by SSR molecular markers showed that: There were differences between the two basic lines and the four improved lines.The similarity coefficients were between 0.55 and0.875.There was obvious genetic polymorphism between the basic lines and the improved lines.The two basic lines and the four improved lines belonged to different materials.2.The genetic gain analysis: There were significant or extremely significant differences between the two improved lines and the basic lines in the yield traits,lodging resistance yield and lodging resistance.Among the suitable harvest traits,the second-round improvement line M6(J1608)had better improvement effect on reducing plant height and ear position;Among the yield traits,the second-round improvement line M5(J1518)had better improvement effects on yield per plant,100-grain weight,spike diameter,spike weight,spike length and male spike branch number,while the first-round improvement line M4(J1866)had better improvement effects on grain number per row;In lodging resistance,the first-round improvement line M3(J9D207)had better improvement in internode length-diameter ratio and internode dry matter percentage,while the second-round improvement line M6(J1608)had better improvement in stem tensile strength,stem puncture strength,internode length,internode diameter,internode fresh weight,internode dry weight and unit stem length dry matter weight.3.The analysis of heterosis: The heterosis of 30 hybrid combinations was widespread,among which the hybrid combination Z23(J1595 × J1518)had the highest heterosis(83.7)in yield per plant,followed by the combination Z17(J1598 ×J1518)(80.7),indicating that J1518 was easy to produce combinations with high yield,and had certain application value.4.The analysis of combining ability: The general combining ability of the two-round improved lines was better.The effect value of the second-round improved line M5(J1518)on yield per plant and 100-seed weight was higher than that of the basic line and other improved lines,showing the best performance and the ability to increase yield.Among the special combining ability,the effect value of yield per plant of hybrid J1598 × J1518 was the largest(83.7),and the effect value of 100-seed weight of hybrid J1595 × J1518 was the largest(8.06),indicating that J1518 was easy to combine high yield hybrid combinations.5.The correlation analysis shows that: Plant height,ear position,stem diameter,ear diameter,ear length,ear weight,axial weight,grain number per row,row number per ear,and 100-grain weight were significantly positively correlated with the yield per plant.The number of male spike branches and bald tip were negatively correlated with the yield per plant,and the ear weight and 100-grain weight had the greatest impact on the yield per plant.The Stem tensile strength was significantly or significantly positively correlated with puncture strength,stem diameter,internode dry weight,and dry matter weight per unit stem length. |
PDF Full Text Request