Genetic Diversity Of Germplasm Resources Paspalum Vaginatum And New Varieties Breeding With High Quality And Cold Tolerance

Paspalum vaginalum belongs to the Paspalum genus of Gramineae.It is an important holophyte,and naturally distribute in souther USA,Afeica,Austrilian and Pacific Ocean coastal region.In China,Paspalum vaginatum is naturally distributed in Guangdong,Hainan,Yunnan and Taiwan.Because of the limited the research of Paspalum vaginatum in China,the main varieties of Paspalum vaginatum widely used in China are all imported from USA and the poor adaption problem is very common although the new cultivars have high turf quality and good salt tolerance.In order to breed new varieties of Paspalum vaginatum with good adaption to Chinese natural condition,in order to meet the needs of coastal ecological development,the morphological marker and molecular marker were firstly used to assess genetic diversity among the Paspalum vaginatum germplasm resources collectioned from of Guangdong and Hainan with main cultivars from USA as check,and the turf quality and cold tolerance of native Paspalumvaginatum germplasm resources and introduced cultivars were evaluated with 6 introduced cultivars as control materials.Finally SRAP molecular marker were used to identify and distinction the new varieties of Paspalum vaginatum with high quality and cold tolerance.The main results were stated as followings:1 Study on the genetic diversity of Paspalum vaginatum germplasm resources1.1 The genetic diversity of Paspalum vaginatum on morphological featuresAccording to the six morphological parameters and seven reproductive traits of 42 Paspalum vaginatum germplasm resources,the SPSS 13.0 software were used to analyze the date of morphological characters.The result showed that significant variation were observed for 13 morphological characters among 42 tested seashore paspalum accessions,the maximum genetic variation value was found in the turf height and density with the CV as 30.96%and 29.93%,respectively.The minimum coefficient of variation was found in spikelet length and inflorescence width with CV as 7.58%and 11.11%,respectively.According to the morphological characteristics,the 42 Paspalum vaginatum were divided into six types.1.2 Optimization of SRAP-PCR System Primers Screening in Paspalum vaginatumPaspalum vaginatum P18-2,P55,’Sealsle2000’,’Adalayd’ collected from China and USA were used as experimental materials.Lg(34)orthogonal experiment design including four factors of Mg2+,dNTP,Primer,TaqDNA polymerase were applied to optimize SRAP-PCR amplification system of Paspalum vaginatumin,and the influence of different concentration of template DNA on the amplification were compared.The optimization SRAP-PCR reaction system suitable for Paspalum vaginatum were established.The results showed that the optimal SRAP-PCR reaction system was 10 × PCR buffer lμL,template DNA 50 ng,Mg2+2.50 mmol/L,dNTP 150 μmol/L,primer 0.4 μmol/L and TaqDNA polymerase 1.5 U in 10 μL total reaction system.Eighty-three pairs of primers were screened with stable amplification and legible bands form 100 SRAP primers with this system,and forty-four pairs of primers with rich polymorphism among 4 tested materials were screened from 83 pairs of primers.1.3 The genetic diversity of Paspalum vaginatum based on sequence-related amplified polymorphism(SRAP)analysisThe genetic diversity of 42 Paspalum vaginatum germplasm resources were analyzed based on SRAP(Sequence-Related Amplified Polymorphism)molecule marker technology.The results showed 30 primer combinations amplified 374 clearly bands in which 321 were polymorphic,the percentage of polymorphisms was 85.83%.Genetic similarity coefficie was relatively high among six introduced eultivars,the genetic similarity coefficient between introduced eultivars and domestic germplasm were low.The 42 Paspalum vaginatum were grouped into seven major groups based on UPGM.2.The evaluation of turf quality of Paspalum vaginatum germplasm resourcesThe turf quality of 42 Paspalum vaginatum germplasm resources were evaluated by 9 main indexes.The result showed ’Seadwarf’ has best turf qualitywith the tuef quality as 7.91,followed by ’Platinum TE’ with turf quality as 7.82.The P55 ranks 4th with turf quality as 7.55,and higher than other 3 introduced varieties.The other 9 Paspalum vaginatumgermplasm resources including P68、P17、P38、P56、P33、P40、P14、P50 and P02 aslo perform good in the experiment.3 Evaluatioa of cold tolerance of Paspalum vaginatum germplasm resourcesThe cold tolerance of 37 national Paspalum vaginatum germplasm resources were estimated by the means of electrolyte leakage rate and stolon regrowth experiment with six introduced cultivars,as the check in the experiment.The results showed that P49、’Salam’、’Seaspray’、P42、P13、’Adalayd’、P56、P60 and P06 have the best cold tolerance of leaves among all tested samples.P55(1)、P05、P09、P18-2、P37、P27、P55、P28、P29、P33 3、P54、P30、’Seadwarf’、P68 could survive after low temperature stress.The result of electrolyte leakage rate and stolon regrowth experiment all showed P18-2、P37 and P27 were better in cold resistance.4 The DNA fingerprinting of high quality and cold resistance of Pcaspalum vaginatum germplasm resourcesSRAP markers were used to analyze the DNA fingerprinting of 8 Paspalum vaginatum germplasm resources and 6 introduced varieties.The result showed 18 primer combinations amplified 312 clearly bands in which 234 was polymorphic.The percentage of polymorphisns was 75%.Me7Eml and MelEm10 were able to distinguish each tested cultivar from others by polymorphic bands.Me7Eml and MelEmlO were able to distinguish each tested cultivar from others by polymorphic bands.