| How to improve the maize grain yield has been an important topic of the research of maize,and lodging is one of the important factors that reduce the maize yield and quality.Lodging greatly endangers to the maize harvest mechanization and production.Therefore,solving the lodging problem is of great importance to improve corn production and ensure food security in China.The stalk resistance of maize hybrids was closely related to plant height,ear height,node thickness,and stalk puncture strength,and the parents of the hybrids had significant effects on these traits.However,the correlation between lodging resistance and the parents of different high maize hybrid lines(F1)and the heterosis difference of lodging resistance of different high maize hybrid lines is relatively weak.These key problems concerning lodging resistance of maize hybrid lines need to be solved urgently.Therefore,this research selects 17 different plant height of maize hybrids and their parental inbred lines as test material,divided into three types: short-stalk,medium-stalk and high-stalk,under the condition of the planting density of 90000 plants/hm2,determination of plant form,stalk puncture strength,lodging rate index,analysis of the lodging resistance differences between different types of plant height.The main results were as follows:(1)Analysis of plant traits and heterosis of maize hybrids of different plant height typesThe plant height,ear height and ear position coefficients showed that dwarf stalk <medium stalk <high stalk and the difference was significant,The spike height and spike location coefficient of Jiushenghe 257 were the highest,which were 119.2cm and 0.41 cm,respectively.DM1114 of dwarf type was the lowest,which was 69.2cm and 0.29 cm,respectively.the supermaternal advantage of plant height,supermaternal advantage and middle parent advantage all showed positive advantage,and the supermaternal advantage of plant height showed that dwarf stalk <medium stalk <high stalk.The super-parental advantage and midparental advantage of medium stalk and high stalk ear position height are positive advantage.The superparental advantage,mid-parental advantage and hybrid advantage index of ear position high,ear position coefficient of dwarf stalk <medium stalk <high stalk,and the hybrid advantage of ear position high of dwarf stalk material differed significantly from the other two materials.The super-mother,super-parent and mid-parent advantages of dwarf and medium stalk ear position coefficients were negative,while the supermother and mid-parent advantages of tall stalk were positive.(2)Analysis of stalk morphology and heterosis of maize hybrids of different plant height typesThe length of internodes at the base of maize stalk was dwarf stalk < medium stalk <tall stalk,and the stalk thickness coefficient was dwarf stalk > medium stalk > high stalk,and there was no significant difference between different plant high types in terms of node thickness.The node length and stalk thickness coefficients of the medium-stalk and high-stalk materials differed significantly from their two parents,with the node length significantly increasing and the node thickness coefficient significantly decreasing as the plant hight increased.The basal internode length hybrid advantage of the medium-stalk and high-stalk materials was positive,and the stalk thickness coefficients were negative for all three types and had dwarf values.The supermaternal advantage,suprapaternal advantage and hybrid advantage index of basal internode length all showed that dwarf stalk <medium stalk<high stalk.All the hybrid advantages of basal internode length of dwarf stalk differed significantly from the remaining two plant high types of materials.stalk thickness coefficient heterosis index of dwarf stalk > medium stalk > high stalk.(3)Analysis of node number difference of hybrids with different plant height typesThere were some differences in the total number of segments of different maize hybrids.The total number of nodes of dwarf varieties was between 11 and 13.Tall culm types are the most common,usually13-16 nodes,and the difference is significant.There was no significant difference in the number of upper segments among different types of spike.The number of lower spike segments is the highest in tall stalk type(7-8 segments),and the lowest in short stalk type(5-6 segments),which is significantly different from that in medium and tall stalk types..(4)Analysis of stalk puncture strength,lodging rate and hybrid advantage of maize hybrids of different plant height typesThe stalk puncture strength showed that dwarf stalk > medium stalk > high stalk.There were significant differences between dwarf and tall culm types.The superiority of superparent,superparent and middle parent in stalk puncture intensity of maize hybrids of different plant height types showed positive superiority,and the superiority of superparent was greater than that of superparent,and all of them were low > medium > high culm.The heterosis difference between high culm and low culm material was significant.Corn stalk puncture intensity was negatively correlated with plant height,ear height and basal internode length.Total lodging rate was significantly negatively correlated with puncture intensity and positively correlated with panicle position coefficient.The lodging rate of dwarf type was the lowest,no stem folding occurred,and the total lodging rate was 1%.The average stem folding rate was 2%,and the total lodging rate was 4%.Therefore,dwarf varieties should be selected in production practice to prevent lodging.Due to the high superparent advantage of plant height,the inbred lines with lower plant height should be selected as the female parent in the breeding process of lodging-resistant varieties,which is beneficial to improve the lodging-resistance of the hybrid.Therefore,dwarf varieties should be selected in production practice to prevent lodging. |
PDF Full Text Request