Improvement Effects Of Maize Inbred Line Tie 7922 And Combining Ability With Suwan Lines

The aim of this study was to figure out that the improvement effects contributed by different donor parents on maize inbred line Tie7922 and the improved lines’ combining ability with Suwan germplasms. The difference from improved lines and Tie7922 was analyzed by investigated agronomic traits and genetic variation. In this paper, we selected maize inbred line Tie7922 and its 9 improved lines as female parents, 10 elite Suwan lines was used as testers, NCⅡ incomplete genetic mating was designed to analyze the effects of combining ability for main agronomic traits.Partially Balanced Lattice Design was employed in the field experiment which was done in three typical places. In addition, SSR molecular method was used to reveal the genetic variation among the inbred lines what be used in this paper. The correlation analysis was compared between the effect of combining ability and genetic distance. The results obtained showed as follow: 1, The improvement effect of Tie7922 on combining abilityThe combining ability effect of yield was favorable of Tie7922 and many improved lines that include T123, 1164, QR29, 440-4, 1061, which the first three reached significant level. Otherwise, 440-4 and 1061 have been not got a significant effect but higher than Tie7922. In addition, there was no obvious effect for QR25 and 21170 compared with Tie7922, but A26 and A30 were the worst lines. So, improved lines T123,1164,QR29 have a better yield potential than Tie 7922, 440-4,1061,QR25,21170 could be maintain the high yield combining ability of Tie7922.However, A26 and A30 achieved lower yield potential.Different improvement effect for each improved line achieved on several traits of corn ear. Three of them got a good improvement effect on many traits, namely T123,1164 and QR29.Only two ear traits were improved for 440-4,21170 and QR25,which have a higher combining ability effect. What’s more, 1061,A26 and A30 have a lower combining ability on several ear traits and all are adverse effect.Significantly increased in yield potential of three improved lines T123, 1164 and QR29,which have potential to decrease plant height and ear position except for QR29, all achieved in improving or maintain the high combining ability of Tie7922 conform to the purpose of reduce plant height and ear position. The general combining ability of stem diameter was increased for 440-4, however, the general combining ability effects of plant height and ear position of 21170 were adverse and significant at 0.01 level that was contrary to the purpose. Although, A26 and A30 achieved the best improvement effect in plant height and ear position, but yield and many yield component factor have a bad performance which not fit the first idea.For flowering traits improvement effect,the improved line 1164 have a clear trend to delay tasseling stage,QR29 was delay with powder period, and the tasseling stage, powder period, and silking stage could be earlier of A30. 2, Agronomic traits difference of improved linesTo compared with maize inbred line Tie7922, nine improved lines have difference in many agronomic traits but not significant. Three improved lines A26, QR25, T123 have declined in plant height and ear position which A26 was the shortest, however, 1061, A30 and 1164 have decreased in ear position but a little increased in plant height. Flowering days be early more than 3 days were 21170, A26, A30, T123, otherwise, QR29 and 1164 obviously delay. 3, Genetic variation of improved lines and Tie7922It was showed that different donors and chosen direction leaded real genetic variation because of bigger difference between improved lines and Tie7922, which revealed by the alleles detected with SSR makers on maize 10 chromosomes. The number of alleles that ordered form more to less was: QR29 > A30 > 21170 > Tie7922 > T123 > QR25 > 1164 > 1061 > A26 >440-4,which QR29 was the most while 440-4 was the least. For Tie7922, the number on the 1 chromosome was the most among 10 lines and have more than Tie7922 11; T123 was more than Tie7922 just on 1,10 chromosomes, but less on the other chromosome; 1164 only have three alleles on the 5 chromosome; the number of alleles on all chromosome of A26 or 440-4 were less than Tie7922 except for the 10 or 1 chromosome. To analysis the genetic similarity coefficient, many results would be obtained as follow: the biggest similarity with Tie7922 was 1061 and QR25, the smallest was T123. In addition, the genetic similarity coefficient among nine improved lines was from 0.6357 to 0.8522, QR25 and 1164 have the largest value but the minimum was 440-4 with T123. 4, Comprehensive evaluation and potential utilization of new improved linesThe maize inbred lines Tie7922 have good modified and the improvement effects were different among them.T123,1164,QR29 and 440-4 were the better lines,1061,QR25 and 21170 almost as the same as Tie7922,A26 and A30 were the worst lines.Therefore, T123、1164,QR29 and 440-4 have higher utilization potential than the others.The average yield in this experiment(kg/666.7m2) was as much as 665.5kg and combinations that exceeded average yield accounted for 53% and three strong hybrids crosses were be chosen,which were 1164×S273,QR29×927 and T123×S65,namely. This results clearly showed that Improved lines × Suwan lines was a good hybrid model and could indicated that Reid × Suwan was a useful heterosis pattern in southwest china. 5,Correlation analysis of molecular genetic distance with yield and combining ability.There was a significant positive correlation that molecular genetic distance with yield and comparison heterosis(r=0.37). However there was no significant correlation between GD and special combining ability. What’s more, the correlation between GD and total combining ability was obvious just for a few traits, but not certain with plant traits and flowering traits. There was a bigger correlation coefficient that yield with total combining ability effect, total of general combining ability effect in most traits, which yield with total combining ability of yield reached the biggest value(r=1).In addition, the relationship between yield and special combining ability was not as obvious as other two combining ability index. The correlation of yield per plot with combining ability was greater than GD with combining ability.