| Eggplant(Solanum melongena L.),belonging to Solanaceae,is widely cultivated throughout China.In the Yangtze River basin and its areas south of China,due to seasonal rainfall,the growth of eggplant is extremely vulnerable to rain.If the soil was too wet,the leaves of eggplant will turn yellow and the plants will wilted or even die,seriously affecting eggplant production.This study extensively collected all kinds of eggplant materials(including breeding materials,cultivated species,cultivated and wild species,et al.),according to the characters of different sources and materials,selected 219 eggplant germplasm resources to identify the waterlogging tolerance of eggplant.The varieties with different tolerance to waterlogging were filtered and the extreme resistant cultivars were selected to construct genetic populations.At the same time,the changes of physiology indexes of eggplant seedlings during and after waterlogging stress were studied.The genetic populations were subjected to a genetic model analysis for waterlogging tolerance and phenotype-genotype association analysis was used to find marker loci related to waterlogging tolerance in eggplants.The results were showed as follows:1.The tolerance recovery index of the 219 germplasm resources was between 0-90.54,and the difference on the waterlogging tolerance was obviously.Among them,84 had strong waterlogging tolerance,109 had moderate waterlogging tolerance,and 26 had weak waterlogging tolerance.The homozygous material 08C-02 was chosen as the resistant male parent from a group of materials with strong waterlogging tolerance.Based on the recovery index value,the eggplant inbred line 09-12-3 was selected from the weak tolerance group as the female parent.2.Among 6 eggplant cultivars with different waterlogging tolerance,the activities of SOD,POD and CAT in the early stage of waterlogging stress increased in seedling stage.With the prolongation of stress time,the activity of antioxidant enzymes gradually decreased.The varieties with strong waterlogging tolerance(08C-02,Suixianziqie,and Xi’an Lvqie)had smaller declines than the weak tolerant eggplant varieties(09-12-3,Anyang Ziguan and Yinqie No.1).Compared with weak tolerant varieties,the malondialdehyde(MDA)content was smaller,the increase of soluble sugar content was larger,and the decrease of chlorophyll content was smaller in strong tolerant varities.In the recovery period,the antioxidative enzyme activity,malondialdehyde(MDA)content,soluble sugar content and chlorophyll content of six eggplant varieties all recovered to varying degrees,and the varieties with strong tolerance were more likely to return to the control level.3.The waterlogging tolerance trait of eggplant was controlled by one pair of additive-dominant major gene plus additive-dominant-epistatic polygene model(D-0).The main gene showed a positive additive effect with an effect value of 0.1918 and a negative dominant effect with an effect value of-0.0042.The absolute value of the dominance degree of the major gene was 0.0219.The heritability of major gene in F2:3 population is 82.58%,the heritability of polygene was 6.11%and the environmental was 11.31%.The above results showed that,early generation selection was good for waterlogging tolerance breeding of eggplant.4.Through analysis on the population structure,219 eggplant varieties can be divided into 3 subgroups.196 SSR loci of the 8525 kinds of pairwise combinations,based on statistical probability(p<0.01)the imbalance of site pairs of site 771,account for 9.04%of the total number of loci combination.27 SSR markers were found to significantly associate with watrelogging recovery index of eggplant by association analysis based on population structure. |
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