Studies On The Cytology Of Buckwheat Interspecific Hybrids And The Effects Of Environment On Yield And Quality Of New Types Of Tartary Buckwheat

Buckwheat has higher nutritional value and health care value than normal cereal crop.China as one of the main producing areas of buckwheat,is rich in buckwheat resources,but its research on buckwheat genetics and breeding is later than Japan and Europe and fall behind on the technology relatively.In recent years,on the basis of sellection breeding and mutagenesis breeding,the researches on cross breeding and interspecific cross breeding et al has been carried out,especially the interspecific cross breeding of buckwheat which has made breakthrough progress.However,the cytological basis,genetic stability and adaptability on the obtained interspecific hybrids are still unclear.Cytological observation was carried out on the materials of F.tataricum ×cymosum,F.giganteum×cymosum,F.giganteum×F.megaspartanium,F.giganteum×F.esculentum obtained during from 2014 to 2017 were carried out,including mitotic chromosome karyotype analysis,chromosome behavior during meiosis,metaphase I chromosome pairing configuration and pollen fertility.Tartary buckwheat（new type of tartary buckwheat,that is,rice tartary buchwheat and perennial tartary buckwheat）with stable performance for at least three successive generations was cultivated under different environmental conditions（different seasons,different locations）,and its main agronomic traits,yield and quality（total flavonoid content,crude protein content）were determined and analyzed in order to provide scientific basis for buckwheat breeding and promotion of new type of tartary buckwheat with high yield and quality.The main results are as follows:1.All parents of the tested crosses were normally fertile,and all inspecific hybrids were completely sterile except the fertile hybrids from the cross F.tataricum×cymosum the results of pollen fertility of all parents and hybrids showed that all hybrids with infertility had a lower Iodine dyeing rate than fertile parent and fertile hybrids.2.The karyotype formulas（karyotypes）of chromosomes at mitosis metaphase and the pairing configuration of pollen mother cells at metaphase I in all hybrids and their parents were as follows:diploid parent materials Guihongtian No.1[2n=2x=16=8m（EE）],0.28I+7.86II;Dayeqiao[2n=2x=16=8sm+8m（MM）],0.22I+7.89 II;Jinqiao No.12n=2x=16=16m（MM）,1.54I+7.23II;Guihongtian No.1[2n=2x=16=16m（EE）];autotetraploid long black grain tartary buckwheat [2n=4x=32=32m（TTTT）],3.82 I+10.89 II+0.56 III+1.18IV;DakuNo.1[2n=4x=32=4sm+28m（TTTT）],4.54I+9.8II+0.26III+1.77IV;artificially doubled tetraploid materials Gui Ai Jinqiao No.1[2n=4x=32=32m（MMMM）],6.45I+4.68 II+0.33 III+1.80 IV,Datian No.1[2n=4x=32=32m（EEEE）],3.97I+11.13II+0.31III+1.21IV;heterotropictetraploid parental materials were Hongxin jinqiao[16m（MM）,2sm+14m（M′M′）],1.58I+11.94II+0.14III+1.53IV,Juqiao[2sm+14m（MM）,12m+4M（TT）],2.79I+14.58II+0.08III+0.32IV;The hybrid F₁tetraploid fertile materials:autotetraploid long black tartary buckwheat×Hongxinjinqiao F₁[1sm+7m（M）,1sm+7m（M′）,14m+2M（TT）],3.06 I+13.07 II+0.18III+0.57IV;The hybrid F₁ tetraploid male sterile materials were Juqiao×Hongxinjinqiao F₁[16m（MM）,1sm+7m（M′）,8m（T）,5.73I+9.83II+0.07III+1.60IV.The hybrid F₁ triploid materials Juqiao╳Guihongtian No.1 F₁[8m（M）,8m（E）,8m（T）],5.66I+4.31II+2.80III+0.33IV;Juqiao×Dayeqiao F₁[16m（MM）,1sm+7m（T）],6.45 I+4.68 II+0.33 III+1.80 IV;The hybrid F₂ materials Daku No.1×Hongxinjinqiao F₂ sterile plants[1sm+7m（M）,1sm+7m（M′）,8m（T）],4.00 I+4.89 II+2.82III+0.44 IV;The hybrid F₂ inbred plants Daku No.1╳Hongxin Jinqiao F₂╳GuiaiJinqiao No.1[16m（MM）,5sm+3m（M′）,1sm +7m（T）],6.64I+11.27II+0.18III+0.57IV;The materials of high-generation hybrid lines are Guiduo Ku 003[3sm+5m（M）,2sm+6m（M′）,16m（TT）],2.61I+12.32II+0.02III+1.17IV.It was found that diploid buckwheat was more stable than tetraploid buckwheat,and the plants with high bivalent frequency and low monovalent frequency were fertile.There were abnormal behaviors such as monovalent,chromosome bridge,backward chromosome,polyvalent and excessive micronuclei in the PMC meiosis of hybrids.In addition,the genetic stability index of both parents and hybrids was statistically analyzed,and the genetic stability index of parents reached 86%,and those of the hybrids are lower than them.3.The studies on the effects of sowing season and planting methods on the main agronomic traits of perennial tartary buckwheat,six new perennial tartary buckwheat lines（Fagopyrum tatari-cymosum）showed that the effects of different sowing seasons on pollen fertility,total seed set,effective rate of seed set,plant height,main stem diameter,main stem branching number,main stem node number,100-grain weight,grain number per plant and yield of main inflorescence of new perennial tartary buckwheat lines reach significant or extremely significant level,and the effects of autumn sowing on pollen of main inflorescence reach significant or extremely significant level.Fertility rate,total seed set,effective rate of seed set,number of branches of main stem,100-grain weight,grain number per plant and yield per plant under autumn sowing are significantly higher than those under spring sowing;Plant height,diameter of main stem and number of nodes of main stem under autumn sowing were significantly lower than those under spring sowing,and there is no significant difference in the size of main inflorescence flowers and the ratio of length to width of ten grains.The effects of different planting methods on pollen fertility and effective rate of seed set on main inflorescence,number of main stem nodes and 100-grain weight of plant reached significant or extremely significant level.The fertility rate of pollen on regenerated main inflorescence and grain number per plant in autumn are significantly higher than those of autumn seeding.The effective rate of seed set of main inflorescence,the diameter of main stem,number of main stem nodes and 100-grain number of plant are also higher than those of autumn seeding.The grain weight is significantly lower than that of autumn seeding.There are no significant differences of the size of main inflorescence flowers,the total seed set,plant height,number of main stem branches,length-width ratio of grain and yield per plant between autumn regenerating and autumn sowing.The correlation analysis showed that there are the highest correlation coefficient between the effective rate of seed set of main inflorescence and grain number per plant with yield per plant in each growing season.Among all the tested lines,the autumn yield of 1612-241 is significantly higher than that of other lines,and the autumn yield of 1612-16 and 1612-33 are significantly higher than that of the otherseason.The results of this study are helpful to obtain the best lines suitable for sowing on certain season and harvesting on two seasons,and provide clues for the perennial tartary buckwheat breeding in the future.4.There are obvious differences of the yield,total flavonoid content,crude protein content and agronomic traits of rice tartary buckwheat linesamong different ecological zones,and significant interaction effects of yield,total flavonoid content and crude protein content between different varieties of rice tartary buckwheat and in different ecological zones,among varieties and different ecological zones.Guyuan County in Ningxia is a high-yielding and high-flavonoid planting area of rice tartary buckwheat with the highest yield p to an average value of 1901.55kg/hm²;the total flavonoid content of rice tartary buckwheat cultivated in Guyuan City of Ningxia is the highest,with an average value of 2.98%,which is significantly higher than other places.The crude protein content in Taixing City of Jiangsu Province was the highest,with an average value of 16.87%,significantly higher than that in other places.The effects of ecological factors on Yield and quality are as follows:low latitude and high altitude are the basis of obtaining higher yield of tartary buckwheat;high latitude,low precipitation and high temperature during growth period are the main factors to increase total flavonoids content of tartary buckwheat grain;low latitude,low altitude,low precipitation during growth period and high temperature during growth period are beneficial to increase crude protein content of buckwheat grain.The correlation analysis of ecological factors,agronomic traits,yield and quality showed that low latitude,long growth period,more plump seeds per plant,higher yield per plant and larger seed particles were helpful to improve the yield of tartary buckwheat.It was also found that plant height and 1000-grain weight were the factors affecting the content of total flavonoids,and 1000-grain weight,grain number per plant and grain weight per plant werethe important factors affecting the content of crude protein.