Genetic Analysis And Characteristics Of Zinc,iron Absorption And Distribution In The Different Maize Inbred Lines

The research was performed using inbred lines with significant difference in zinc(iron)concentration of CO109?lv28 ?chen322?qiong51.Three treatments were set up for the inbred lines during the silking stage as follows: 1).Remove the upper leaves of the panicle.2).Remove the lower leaves of the panicle.3).Reserve all leaves.The differences of zinc(iron)concentration and accumulation were analyzed statistically.By using P1,P2,F1,BC1,BC2 and F2 generations obtained from 2 inbred lines(NXR9 and NXR190),another experiment was conducted under zinc fertilized and zinc unfertilized conditions to do genetic analysis of zinc(iron)concentration and accumulation with major gene plus polygene inheritance model.The main results obtained were as follows:1.There are significant genotypic difference of zinc?iron concentration at the same leaf position during silking and mature stages.At the same leaf position,the zinc and iron concentration of line CO109 and lv28 were much higher than that of line chen322 at silking stage.Compared with the intact plants,removal of functional leaves did not affect the zinc and iron concentration of grain,the zinc and iron concentration of the high zinc(iron)concentration inbred lines were still significantly higher than that of the low zinc(iron)inbred lines.2.The accumulation of zinc and iron in the mature stage of inbred lines show a different amplitude increase compared with the silking stage.The inbred line chen322 was increased higher than the two inbred lines with high zinc concentration.From silking to maturity,zinc and iron distribution in grain and leaves was remarkable difference among genotypic lines,and the ratio of zinc distributed to grain was more than 75% in the inbred lines CO109 and lv28,which was significantly higher than that of low zinc inbred lines,which the ratio of zinc distributed to grain was 42.7% in the inbred line chen322.But the ratio of iron distributed to grain was more than 50% in the inbred line Qiong51,which was significantly higher than that of high iron inbred lines,which the ratio of iron distributed to grain was 18.9% in the inbred line CO109.Removal of functional leaves reduced the accumulation of zinc at the mature stage.The decrease range was different among genotypes,and high grain zinc concentration did not mean that the accumulation of grain zinc was necessarily high.3.At the difference zinc treatment level,maize leaf and grain zinc(iron)concentration was controlled by two major gene plus polygene.Heritabilities of major genes were higher than polygenes.Major genes heritabilities were highest in F2 generation,interaction between major genes.At Zn-fertilized,major genes heritabilities of leaf zinc and iron concentration in F2 generation were 81.75% and 41.98% respectively,dominant effect is primary.Major genes heritabilities of grain zinc and iron concentration were 73.38% and 59.44% respectively,and dominant effect is primary.At Zn-unfertilized,Major genes heritabilities of leaf zinc and iron concentration were 76.59% and 68.89% respectively,and additive effect is dominant in zinc concentration,dominant effect is dominant in iron concentration.Major genes heritabilities of grain zinc and iron concentration were 71.78% and 74.25% respectively,and for zinc concentration,one major gene is dominant effect and another major gene is additive effect.Dominant effect is primary in iron concentration.4.At the difference zinc treatment level,maize leaf and grain zinc(iron)accumulation was controlled by two major gene plus polygene.Heritabilities of major genes were higher than polygenes.Major genes heritabilities were highest in F2 generation,interaction between major genes.At Zn-fertilized,Major genes heritabilities of leaf zinc accumulation were 76.59% and 50.53% respectively,and additive effect is primary in zinc accumulation.For iron accumulation,one major gene is dominant effect,and another major gene is additive effect.Major genes heritabilities of grain zinc accumulation were 90.31% and 97.98% respectively,and dominant effect is primary in zinc accumulation.For iron accumulation,one major gene is dominant effect,and another major gene is additive effect.At Zn-unfertilized,Major genes heritabilities of leaf zinc and iron accumulation were 85.83% and 71.47% respectively,and dominant effect is primary.Major genes heritabilities of grain zinc and iron accumulation were 97.96% and 93.15% respectively,and dominant effect is primary in zinc accumulation.For iron accumulation,one major gene is dominant effect,and another major gene is additive effect.In conclusion,the grain zinc and iron were from the uptake of root during grain filing period other than transported from leaves.Compared genotypes with lower grain zinc and iron,the distribution ratio of zinc to grain and iron to leaves in genotypes with higher grain zinc and iron were much higher.Under Zn-unfertilized and Zn-fertilized conditions,concentration and accumulation of maize leaf and grain zinc(iron)were controlled by two major genes plus polygene,and the heritabilities of major genes were higher than polygenes.The interaction of major genes was observed.The parameters such as dominant effect,additive effect and heritabilities were different in different zinc environments,which were greatly affected by zinc application.