| Germplasm resource scarcity has become a bottleneck for maize breeding. Therefore, the innovation about germplasm resource is extremely urgent and play an important part in maize breeding. Space mutation provides a new approach for the innovation of crop germplasm resources and hybrid breeding. In this experiment, the test material were as follows:three inbred lines 08-641,18-599 and RP125 were carried into space by satellites in 2006.7 mutant lines were selected from the offsprings of 08-641 inbred lines,10 mutant lines were selected from the offsprings of RP125 inbred lines, and 9 mutant lines were selected from the offsprings of 18-599 inbred lines. Inbred lines such as Mo17,478, ES40,48-2, Huangzaosi, RP128, Zi330,18 red, 698-3,9636,5311, SAM3001, SCML103 and Jinhuang96B were used as testers, cross combinations were conducted according to incomplete diallel design.84 combinations were successfully got for 08-641 and its descendant lines,110 combinations were successfully got for RP125 and its descendant lines,81 combinations were successfully got for 18-599 and its descendant lines. All the combinations were planted in Xishuangbanna of Yunnan and Yaan of Sichuan respectively. According to randomized block design the test material were plant in two lines,three times repeated.during the growth period.plant height,ear hight,ear length,sterile length,kernel length,rows per ear,kernels per row,100-kernel weight,yield per plant and the shelling percentage 10 agronomic straits were investigated.The combining ability was analyzed with the method of incomplete diallel cross design,we also studied heterosis with Chengdan30 as control lines.The main results were as follows:1.As for 08-641 and its related materials, variance analysis indicated there were 7 traits including plant height, ear height, ear length, sterile length, rows per ear, kernels per row,100-kernel weight with significant difference between different locations, all the traits except the shelling percentage were significantly different among different combinations, there were 7 traits such as plant height, ear length, sterile length, rows per ear, kernels per row,100-kernel weight, yield per plant with significant difference among interactions between locations and combinations.As for RP125 and its related materials, the results of variance analysis indicated there were significant difference for all the investigated traits not only between locations but also among different combinations, among the interactions of locations and combinations,7 traits'difference arrived to the significant levels.As for18-599 and its related materials, variance analysis indicated 7traits including plant height, ear length, sterile length, rows per ear, kernels per row, kernel length and yield per plant with significant difference between different locations, all the traits except the shelling percentage were significantly different among different combinations, there were 6 traits with significant difference among interactions between locations and combinations, they were plant height, ear height, sterile length, kernel depth,100-kernel weight and yield per plant, respectively.2.Combining ability variance analysis indicated that the GCA value of plant height, rows per ear, kernels per row and yield per plant took on significant difference among 08-641 and its mutant lines. The GCA value of plant height, ear height, ear length and yield per plant show significant difference among Rp125 and its mutant lines. As for 18-599 and its mutant lines, only the GCA value of rows per ear and yield per plant arrived to significnat level. Further analysis indicated that 6 mutant lines for rows per ear,5 mutant lines for kernels per row,1 mutant line for yield per plant have significant difference compared to the 08-641 which did not be carried into space. As for RP125, 8 mutant lines for ear length,5 mutant lines for yield per plant took on significant difference with the RP125 itself which did not be carried into space. Compared to the control 18-599, Only 4 mutant lines showed significant difference for the trait of rows per ear. All the results display space flight can induce the change in GCA value, but it is different not only in the extent but also in the direction for the same material of different traits or for same trait of different materials.3.Contrast to the hybrid of Chengdan 30 which were considered as the check, the control superiority were calculated for all the combonations for yield per plant. Among the 08-641 and its mutant lines, there were 7 combinations with control superiority over 10%,1 combination with control superiority over 30%. As for RP125 and its mutant lines, there were 26 combinations with control superiority over 10%,4 combinations control superiority over 20%,4 combinations control superiority over 30% and 7 combinations control superiority over40%. Among the 18-599 and its mutant lines, there were 27 combinations with control superiority over 10%,2 combination with control superiority over 20% and 2 combination with control superiority over 30%. The combinations of S91576×9636, Y92803×48-2, Y93078×48-2 and Y93235×330 took on control superiority over 10% not only in Yunnan but also in Sichuan, Which indicated that these combinations may have higher utilization potential. Analyzing their parients of these combinations, we found that tester lines9636,48-2,5311, SCML103 and Zi330 appeared more frequently. |
PDF Full Text Request