Evaluation And Utilization Of Functional Markers Associated With Pre-harvest Sprouting Resistance In Wheat Cultivars

In the present study,the main aims were to:1)evaluate on the pre-sprouting harvest（PHS）resistances of 326 Chinese wheat cultivars in three environmwnts and screen the PHS-resistant materials;2)evaluate the effects of the functional markers of the known genes associated with PHS-resistance and identify major-effect genes;3)validate these main-effect genes using genetic populations.The main reuslts are as follows:1.The mean germination index（GI）of 326 cultivars mainly collected from the Northern Winter Wheat Zone（NWWZ）and Yellow and Huai River Valley Winter Wheat Zone（YHWZ）was 47.5%across three evrinomnets,with the ranging from 11.6%to 89.8%.The GIs of 16 cultivars（8 white-grainedand 8red-grained cultivars）were lower than 20%,and they could be used as donors to develop PHS-resistant cultivars and identify PHS-resistant genes.2.The effects of different alleles at each locus of 15 loci associated with PHS resistance were analyzed,and results showed that 8 loci were significantly associated with PHS-resistance.The effects of8 loci in order are Ta PHS1-222,Tamyb10-D1,Ta PHS1-666,Ta PHS1-646,Ta Sdr-2B,Ta Vp1-A,Ta MFT-A1,Ta MFT-A2.Among them,the allele Ta PHS1-222C at Ta PHS1-222 had the highest effect on PHS-resistance,and the mean GI of cultivars carrying the allele Ta PHS1-222C was 28.2%.The frequence of this allele was only 4.3%,indicating that it is necessary to increase the frequencies of Ta PHS1-222C allele for improvement of PHS resistance.3.Two genetic populations were developed by crossing the high susceptible cultivar Lunxuan 13（Ta PHS1-222T/Ta Sdr-2Ba/Vp-1Ba）to PHS-resistant cultivars Bainong 3217（Ta PHS1-222C/Ta Sdr-2Bb/Vp-1Ba）and Fengchan 3（Ta PHS1-222C/Ta Sdr-2Bb/Vp-1Bc）,respectively.The mean GIs of Lunxuan 13×Bainong 3217 population were 62.2%and 36.5%in the F₂ and F_2:3 generations,and the ranges were 23.4%～92.9%and 5.1%～72.4%,respectively.Compared to the recipient parent Lunxuan 13,the alleles Ta PHS1-222C,Ta Sdr-2Bb and pyramiding two alleles reduced the GI by 29.9%and 40.7%,27.1%and 40.0%,and 32.7%and 44.3%（P<0.01）in the F₂ and F_2:3 generations,respectively.The mean GIs of Lunxuan 13×Fengchan 3 population were 32.3%and 52.4%in the F₂ and F_2:3 generation,and the ranges were 0.9%～80.4%and 2.3%～93.3%,respectively.Compared to Lunxuan 13,the PHS-resistant alleles Ta PHS1-222C,Ta Sdr-2Bb,Ta Vp1-B and pyramiding three alleles reduced the GI by 32.3%,and46.1%,30.1%and 41.7%,22.9%and 39.9%,and 45.4%and 49.9%（P<0.01）,respectively.The GIs of more than 90%progenies in the two populations were significantly lower than Lunxuan 13.4.Among 248 wheat cultivars,54.6%of them carried Ppo-A1b allele with low PPO activity at Ppo-A1 locus,and 45.4%of them carried Ppo-A1a allele with high PPO activity.There were signficiant differences of GI between cultivars carrying Ppo-A1b allele（44.3%）and Ppo-A1b allele（49.5%）,but no significant difference in the GI between alleles at the Ppo-D1 locus.5.In the Lunxuan 13（Ppo-A1a/Ppo-A1a）×Jimai 20（Ppo-A1b/Ppo-A1b）population,the GIs were59.5%and 47.0%,and the ranges were 18.1%～90.8%and 19.1%～79.5%in the F₂ and F_2:3 generations,respectively.The mean GIs of Ppo-A1b and Ppo-A1a homozygous genotypes were 51.9%and 61.1%,43.0%and 47.8%in the F₂ and F_2:3 generations,respectively.The activity of PPO and the relative expression level of Ppo-A1 were significantly positively correlated with the GI,suggesting that the Ppo-A1b allele could be effectively used in the marker-assisted selection of PHS-resistant breeding.