Allelic Identification Of Maize Dwarf Mutants And Sensitivity To Exogenous Hormones

Crop dwarfing is an effective way to improve crop lodging resistance and economic yield.Therefore,it is vital to extend dwarf materials and study their dwarfing characteristics to promote crop dwarf breeding.In this study,five maize dwarf mutants were used to compare the diffences of main agronomic traits with corresponding wild-type,for obtaining their dwarfing characteristics;By Griffing method 4,the allele relationship between dwarf mutants was identified by plant height and ear height of F1 and F2;The sensitivity of mutants to exogenous hormones was analyzed through the effects of gibberellin(GA3),auxin(IAA)and Brassinolide(BR)treatment on the growth and endogenous hormone content of mutant seedlings,to investigate the dwarfing mechanism of dwarf mutant.The main results are as follows:1.Compared with the wild type,the plant height of K15d,K78d,R08d,K123d and K125d decreased by 39.22%,42.60%,50.46%,43.19%and 38.68%;The ear height decreased by 69.75%,77.01%,53.42%,38.9%and 57.85%;The difference reached a very significant level.Except for the K125d intemode number increased by 1-2 knots,the lower part of K15d panicle was decreased by 2 knots and the upper part of K123d was increased by 1 knots,but the difference of other materials was not significant;K125d intemodes and K78d lower internodes were markedly thickened;the intemodes of R08d and K123d were uniformly shortened,and the lower internodes of the other 3 materials shortened more obviously.In K15d and K123d,the number of cells in the transverse section decreased,while the numbers of K78d,R08d and K125d cells increased significantly,and the vascular bundle showed a trend of increase.The number of cells in the longitudinal section of the 5 mutants was significantly increased,and the cells became smaller and irregularly arranged.2.The dwarfing genes of K15d,K78d and K125d were equilibrated with br2 according to the results of F,plant height and ear height analysis of 5 dwarf mutants and 114F(br2)combinations.The results of allele identification of dwarf mutant showed that five dwarf mutant materials were composed of Griffing method 4,according to the F1,F2 generation plant height and ear height,K15d,K78d,K125d dwarf mutant gene Alleles,other mutant materials are not allelic.In addition,according to the distribution of F2 plant height,K15d?K78d and R08d stunt characters may be affected by other minor genes,except for a pair of major recessive dwarf genes,which need further study.3.With different concentrations of GA3,IAA and BR,5 dwarf mutants and their wild type treatments were applied.The results showed that 10d seedlings height,15d seedling height and root length were significantly different between different concentrations and materials,and the interaction between concentration and material was also very significant.With the increase of GA3 concentration,5 mutant seedling height increased,except R08d,the remaining 4 mutants can return to the wild type,sensitive to exogenous GA3,As the concentration of IAA increased,the five mutations were lower;With the increase of the BR concentration,the K78d seedlings were low,the K15d and K123d seedlings were different,and the R08d and K125d were higher,but neither could be recovered to the wild type,indicating that the five mutants were not sensitive to IAA and BR.With the increase of the concentration of three exogenous hormones,the root length of the 5 mutants tended to decrease.4.With the processing of 15d by GA3,the content of endogenous GA3 in the seedlings was significantly different in different treatments and material,and the interaction between treatments and materials was significant.With the increase of exogenous GA3 concentration,the content of endogenous GA3 in K15d increased,which may be due to insufficient synthesis of dwarf GA3;K78d,K125d and R08d endogenous GA3 content showed a trend of decrease or increase before,but significantly higher than the corresponding wild type,the dwarf reason is that GA3 pathway is blocked or affected by other factors the content of endogenous GA3;K123d also showed increased and then decreased,and was significantly lower than the wild-type,showed signs of endogenous GA3 synthesis is insufficient,but there was no significant difference between the mutant and the wild type seedlings when the same concentration of exogenous GA3 was applied,the dwarf reason needs further research.