QTL Analysis Of Seed Vigor Related Traits In Wheat DH Population Under Artificial Aging Condition

Seeds have extremely important biological significance in the evolution of plants,at the same time,seeds are the most basic agricultural production materials.Seed vigor is highly heritable,and the expression of vigor is restricted by environmental conditions.The genetic studies of wheat(Triticumaestivum L.)mainly focus on agronomic traits,while the location analysis of wheat seed vigor is less.In this study,the DH population constructed by Hanxuan 10/Lumai 14 was used as a test material to analyze the effects of higher temperature(48 °C)and higher humidity(100% relative humidity)of artificial aging treatment on seed vigor-related traits.And then explore the correlation between vitality indicators and locate QTLs for related traits.The main results are as follows:1.Under six aging treatment conditions,the Germination percentage(GP),germination energy(GE),germination index(GI),seedling length(SL),root length(RL),seedling weight(SW)vitality Index(VI)and simple vitality index(SVI)of DH population wheat continued to decline with the aging time,and the relative electrical conductivity(REC)increased with the aging time.The changing critical point of the related seed vigor traits appeared in the 24h~36h after aging treatment.2.After the aging treatment,the seed traits related to the DH population showed super-parent separation,and the coefficient of variation showed a trend of increasing with the treatment time.3.There is a significant positive correlation between germination percentage(GP),germination energy(GE),germination index(GI),vigor index(VI)and simple vigor index(SVI)of DH population under different aging treatments from E1 to E72.Most of the treatments were also significantly correlated with seedling length(SL),root length(RL)and seedling weight(SW).Under different aging treatment conditions,there were differences in the main seed vigor-related traits of different families in the DH population.4.A total of 50 additive QTLs related to vigor-related traits of wheat seeds were detected,which were distributed on 12 chromosomes of 1B,2D,3A,3B,3D,4A,4D,5A,5B,5D,6D and 7A.The chromosome with the most QTL locus is 5D,which contains 18 additive QTLs;and followed by chromosome 5B,which contains 14 additive QTLs;then chromosome 5A,which contains 8 additive QTLs.A total of 27 pairs of epistatic QTLs were detected,distributed in all chromosomes except 5D,6A and 7D.It indicated that the additive effect of QTL had greater influence on seed vigor trait than epistatic effect.5.The 7 traits including of germination percentage(GP),germination energy(GE),germination index(GI),seedling length(SL),root length(RL),seedling weight(SW)vitality Index(VI)and simple vitality index(SVI)were detected a stable expression of the epistatic QTL at least.6.Three additive QTL hotspots were detected.One QTL related to the 6 traits of GE,GI,SL,RL,VI and SVI was detected on chromosome 5B;One QTL related to the 7 traits of GP,GE,GI,SL,RL,VI and SVI were detected on 5D chromosome;one QTL related to the VI and SVI was detected on the 5D chromosome.At the same time,two epistatic QTL hotspots were detected,which were located on chromosomes 3B and 6B,respectively,controlling GEl,GI,VI and SVI.These hotspots can provide reference for the cloning,functional verification and molecular marker-assisted selection breeding of wheat seed vigor related genes in the future.