| Golden Tartary buckwheat（Fagopyrum tatari-cymosum Chen）is a double-diploid hybrid obtained by widely crossing annual Tartary buckwheat with perennial golden buckwheat and.It is a new crop with certain perennial characteristics and can be harversted twice sowing once.Compared with the annual Tartary buckwheat,the grain size was larger,the quality was better,the drought resistance and barren resistance were stronger,and the regeneration ability was stronger.Therefore,golden Tartary buckwheat has great development potential and value of research and utilization.In particular,golden Tartary buckwheat is derived from the perennial wild golden buckwheat species with strong drought resistance and barren resistance,and its drought resistance is lacking in research.In this study,84 accessions of golden Tartary buckwheat（F.tatari-cymosum Chen）were used as the main research materials,and 6 accessions of cultivated Tartary buckwheat（F.tataricum Gaertn.）,5 accessions of wild Tartary buckwheat（F.tataricum Gaertn.）,5 accessions of rice bitter buckwheat（F.tataricum Gaertn.）,5 sweet buckwheat（F.esculentum Moench）and 1 golden buckwheat（F.cymosum Meissn.）were used as controls,totaling 106 germplasms.And their agronomic traits,drought resistance performance and molecular markers were studied.The main results obtained are as follows:（1）Evaluation of agronomic traits: 106 buckwheat germplasms were investigated for four agronomic traits,including yield per mu,plant height,grain weight per plant,and number of main stem branches.In terms of yield,golden Tartary buckwheat has the yield of 79.80Kg（variation range is 7.53-136,coefficient of variation 0.23）,which is higher than the average yield per mu of cultivated Tartary buckwheat（mean 72.77 Kg,variation range 55.3-83.45,coefficient of variation 0.15）,wild Tartary buckwheat rice Tartary buckwheat（mean 22.60 Kg,variation range 10.62-35.89,coefficient of variation 0.47）,rice and Tartary buckwheat（mean 23.90 Kg,variation range of 18.90-27.30,coefficient of variation 0.13）,but lower than sweet buckwheat average yield per mu（mean 136.89 Kg,variation range 126.05-164.60,with a coefficient of variation of 0.12）;in terms of plant height,the average plant height of golden Tartary buckwheat is 88.17 cm（the range of variation 11-122,and the coefficient of variation 0.16）,which is higher than the average plant height of conventionally cultivated Tartary buckwheat（mean 74.98 cm,the range of variation 68.60-83.2,the coefficient of variation 0.07）,wild Tartary buckwheat（mean 66.22 cm,the range of variation 43.80-83.50,the coefficient of variation 0.27）,and rice Tartary buckwheat（mean 65.62 cm,the range of variation 59.70-69.30,the variation 0.27）.coefficient of 0.06),and sweet buckwheat（mean 77.92 cm,the range of variation 69.81-83.90,the coefficient of variation 0.07）;in terms of grain weight per plant,the average grain weight per plant of golden Tartary buckwheat is 7.59 g,with the variation range of 2.62-12.68 and the coefficient of variation of 0.35),higher than the average grain weight per plant of cultivated Tartary buckwheat（mean 5.71 g,variation range 4.45-8.22,coefficient of variation 0.24）,wild Tartary buckwheat（mean 3.55 g,variation range 2.10-5.69,coefficient of variation 0.38）,rice Tartary buckwheat（mean 2.80 g,the range of variation 2.02-3.42,the coefficient of variation 0.21）,but lower than that of sweet buckwheat（mean 9.30 g,the range of variation 6.53-11.61,and the coefficient of variation 0.21）.Correlation analysis showed that the yield per mu of golden Tartary buckwheat was significantly positively correlated with the number of main stem branches（r=0.415**）and the number of grains per plant（r=0.234**）.r=0.897*).In other types of buckwheat,there was no significant correlation between these agronomic traits.（2）Identification of drought resistance at germination stage: set the PEG concentration gradient as 0%,5%,10%,15%,20%,25%,at a temperature of 25°C,humidity between 70%-85%,under the condition of 12 hours of light and dark,the germination simulation drought resistance test of four types of buckwheat varieties was carried out,and the drought resistance indicators such as germination rate,germination potential and root length were measured.It was found that 20% PEG treatment was the most suitable for drought resistance identification,and the bud length and root length indicators were sensitive to response,which can be used as an indicator for the identification of drought resistance.The drought resistance of 106 buckwheat materials at the germination stage was identified by three treatments of 0%,10% and 20% PEG.It was found that the germination potential,germination rate,root length and shoot length of Tartary buckwheat showed performance under 10% and 20% PEG stress.Compared with the control,the germination potential,germination rate,root length and shoot length were significantly decreased under 20% PEG stress compared with 10% PEG stress.The germination potential,root length,shoot length index of golden Tartary buckwheat buckwheat decreased significantly compared with the control under 10% and 20% PEG,and the germination potential,root length,shoot length and main stem diameter under 20% PEG stress were lower than 10% PEG stress.The germination rate,shoot length and root length index of cultivated Tartary buckwheat showed a significant decrease under 10% and 20% PEG stress compared with the control,and the bud length and root length index under 20% PEG stress decreased significantly compared with 10% PEG stress.Wild Tartary buckwheat showed a significant decrease in root length,germination potential and germination rate index under 20% PEG stress compared with the control,and under 20% PEG stress compared with 10% PEG stress,the germination rate and germination rate index decreased significantly,10% PEG treatment only had significant difference with the control group in root length index.The germination potential and bud length of sweet buckwheat decreased significantly under 20% PEG stress compared with the control group and 10% PEG treatment,and there was no significant difference between the 10% PEG treatment and the control group.The root length index of Tartary buckwheat under 10% and 20% PEG stress showed a significant decrease compared with the control,and there was no significant difference between 20% PEG treatment and 10% PEG treatment.（3）Drought stress in potted seedling stage:A simple canopy was built on the roof,and the normal potted buckwheat seeds germinated to grow to the third true leaf.Seting the control（80% water content）,mild drought stress（50% water content）,and severe drought stress（25% water content）treatment levels,three physiological and biochemical indicators were measured.The results showed that the average POD contents and MDA contents of golden Tartary buckwheat,cultivated Tartary buckwheat,rice Tartary buckwheat,wild Tartary buckwheat and sweet buckwheat were significantly increased in stress group compared with control group,and the soluble protein content of stress group was significantly decreased compared with control group.There were significant differences of the above indicators between heavy stress group and light stress group.（4）Comprehensive evaluation of drought resistance: According to D value and CDC value,each variety is clustered and analyzed,and all varieties（lines）can be divided into 3 categories when the Euclidean distance is 10.The first category is the germplasm with high drought resistance,including 18 materials,that is,15 golden Tartary buckwheat（TC2,TC3,TC7,etc.）,one sweet buckwheat（E3）,and one wild Tartary buckwheat（WT2）,one accession of cultivated Tartary buckwheat（CT3）,accounting for 16.98% of the tested germplasm;Class II is the intermediate type,with 53 accessions,including 42 accessions of golden Tartary buckwheat（TC5,TC6,TC25,etc.）,two conventionally cultivated Tartary buckwheat（CT1,CT5）,three wild Tartary buckwheat（WT3,WT4,WT5）,four rice Tartary buckwheat（RT1,RT2,RT4,RT5）,two sweet buckwheat（E1,E4）,accounting for the test lines 50.00%.The third category is sensitive germplasm,with a total of 35 accessions,including 27 accessions of Tartary buckwheat（TC1,TC14,TC17,etc.）,three accessions of conventionally cultivated Tartary buckwheat（CT2,CT4,CT6）,one accession of wild Tartary buckwheat（WT1）,one rice Tartary buckwheat lines（RT3）,two sweet buckwheat lines（E2,E5）,and one rice Tartary buckwheat,accounting for 33.02%,which can also be roughly divided into 3 subclasses B1,B2,B3,among which B3 is highly sensitive material,TC37,TC84,TC22,TC56.Through principal component analysis,comprehensive D value and CDC value,the drought resistance of 106 buckwheat germplasms were roughly divided into 5 categories,and the top 5 varieties with strong drought resistance were screened out,namely TC3,TC5,TC8,TC40,TC55.（4）SSR molecular marker: 80 pairs of primers were used as the primary screening of primers in this experiment.The results showed that 65 pairs of primers（81.25%）had obvious amplification bands,of which 25 pairs of primers showed obvious polymorphism,accounting for the polymorphism rate of 31.25%,and a total of 84 polymorphism bands were obtained.Among them,5 pairs of primers were associated with agronomic traits,and 13 pairs of markers were associated with drought resistance.According to the polymorphism results of 25 pairs of primers,the 106 buckwheat germplasms collected were clustered by ntsys software.It was found that when the genetic coefficient was 0.6,the 106 buckwheat germplasms could be divided into 2 categories,category I.Mainly sweet buckwheat,class II includes golden Tartary buckwheat and various types of Tartary buckwheat. |
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