| Auricularia cornea is one of the edible fungi of the genus Auricularia.It is known as "jellyfish skin on trees" and is a natural edible and medicinal fungus.It is the sixth largest edible fungus in China.With the gradual expansion of industrial scale and the increasing demand for good varieties in the market,germplasm resources are the basis for breeding of good varieties.Comprehensive and scientific evaluation of germplasm resources is conducive to the scientific utilization of good germplasm characteristics.Therefore,this study was evaluated the germplasm resources of A.cornea from four aspects: cytology,morphology,biochemistry,molecular markers,established a comprehensive evaluation system,and screened the excellent strains with potential for development.The results were as follows:(1)Cytological evaluation,the somatic incompatibility of 45 strains(14 wild strains,13 cultivated strains and 18 hybrid strains)of A.cornea were evaluated.990 confrontation culture combinations were prepared.The results showed that 99.89% of the combinations had antagonistic lines,indicating that the somatic cells of these strains were incompatible and had different physiological characteristics.Only two strains Ac2 and Ac4 had no antagonistic lines,indicating that the two strains had close somatic cell affinity.No difference in physiological characteristics was found.(2)Cytological evaluation,agronomic traits investigation of A.cornea.in accordance with DUS standard principle have difference,which can provide scientific basis for the formulation of DUS of A.cornea.The mycelial growth rate was ranged from 1.10 mm/d to 4.70 mm/d at 25 ?.The neat and irregular edges of mycelia was accounted for 24.44% and 75.56% respectively.The colony pigment secretion was divided into obvious and unconspicuous.The ratio was 60% and 40% respectively.The mycelium was produced colloid and no colloid,which was accounted for 20% and 80% respectively.The edge of fruiting body was neat and the wave accounted for 48.89% and 51.11% respectively.The ventral wrinkle of fruiting body had no,few and multiple folds accounted for 33.33% and 35.56% respectively.Among them,the white,light pink and reddish-brown color on the ventral surface of fresh ears accounted for 35.56%,8.88% and 55.56% respectively;the soft and hard texture of ears accounted for 51.11% and 48.89% respectively;the growth period was 86-144 days,and the early,middle and late maturity accounted for 20%,44.44% and 35.56% respectively;and the dry weight of fruiting body was 0.45-6.88 kg per 100 kg dry material.The high-yield,middle-yield and low-yield types accounted for 24.44%,26.66% and 48.9% respectively,and the dry-wet ratio of fruiting body was 14.6%-22.5%.The results of cluster analysis showed that the tested strains could be divided into eight groups,which could better compare the characteristics of the strains.Based on all agronomic traits,two specific A.cornea germplasm,one early maturing strain Ac13 and one high-yield strain Ac15 were screened to provide high quality materials for directional breeding of A.cornea.(3)Biochemistry evaluation,313 bands were detected,the number of bands was varied from 3 to 8,most of which were 5 and 6 bands.There were 36 bands with different mobility(Rf).Rf distribution ranged from 0.261 to 0.585.Among them,the band E18 with Rf 0.423 was the most stable,the frequency of band E14(Rf = 0.400)was 44.4%,and the frequency of band E26(Rf = 0.485)was 44.4%.These bands can be used as high frequency bands of tested strains.When the similarity coefficient was 0.68,it can be divided into two groups.Group I had nine strains,all of which were wild strains.Group II included 36 strains.When the genetic similarity coefficient was 0.715,group II can be divided into two subgroups.Subgroup I had one wild strain,all hybrid strains and cultivated strains.Subgroup II included four strains,all of which were wild strains.In cytological evaluation,Ac2 and Ac4,two strains with no parallel lines,had genetic similarity coefficient of 0.935,which indicated that the latter was more effective than the former in evaluating germplasm resources on A.cornea.(4)Molecular marker evaluation,24 pairs of stable and highly polymorphic SSR primers were screened out from 144 pairs of primers,which were developed based on the whole genome of A.cornea for germplasm resources evaluation.A total of 145 alleles were detected in Pop Gene 1.32,and the ratio of the polymorphism locus was 100%.It was indicated that 24 pairs of SSR primers were abundant polymorphism in A.cornea germplasm.NTSYS-PC cluster analysis showed that when the genetic similarity coefficient was 0.71,the tested strains could be divided into two groups.Group I included 16 hybrid strains and their parents Ac1;Group II included 28 strains,which can be further divided into two subgroups when similarity coefficient was 0.717.Subgroup I was all cultivated strains,Subgroup II was all tested wild strains and two hybrid strains with wild parent strain Ac13.Cluster analysis showed that most of the hybridized,cultivated and wild strains could be separated by SSR markers,and the genetic differences among the strains could be revealed on the molecular level.It was more thorogh than the results of biochemistry evaluation.Therefore SSR molecular markers based on genome development were more suitable for the evaluation of germplasm resources on A.cornea. |
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