Genetic diversity and relationships among cultivated and wild accessions of tartary buckwheat (Fagopyrum tataricum Gaertn.) as revealed by RAPD markers

The methodology of sampling and the selection of a proper marker systemfor the analysis of accessions are major concerns in the evaluation of gene bank material. In our study the RAPD analysis of bulked DNA samples and single seedsDNA was successfully employed to evaluate intra- and inter-population geneticvariability of cultivated and wild tartary buckwheat accessions. The bulkingapproach enabled the distinction of all 40 analysed accessions and theirseparation into geographically well defined clusters. Three wild populations,two from Sichuan and one from Qinghai, formed a group that was geneticallyrelatively distant from wild populations from Tibet and all cultivatedlandraces which, on the other hand, exhibited very close relationships. Thesingle seed study that was used after bulked DNA analysis provided detailedinformation of the genetic variation present within some accessions of specialinterest. A moderate level of genetic variability was detected betweenaccessions and the variability was partitioned into between- andwithin-population components. On average, most of the detected variation ispresent between F. tataricumpopulations. The genetic and geographic distribution of variability is furtherdiscussed. We demonstrated the usefulness of combining bulking and single seedstudy approaches for the effective evaluation of genetic variability inF. tataricum accessions that couldalso have wider applicability in the management of plant genetic resources andphylogenetic studies.     

施肥水平对苦荞产量及生物类黄酮含量的影响

为了提高苦荞的产量和品质,采用正交试验方法,对苦荞在不同施肥水平下的栽培模式进行了试验,以提出苦荞高产和高生物类黄酮含量的最佳施肥水平。结果表明:苦荞在中等肥力的土壤上栽培,产量最高的施肥水平为施25kg/667m2磷肥作底肥,5kg/667m2尿素作追肥,不施复合肥;生物类黄酮含量最高的施肥水平为施12.5kg/667m2复合肥、25kg/666.7m2磷肥作底肥,不追肥。     

荞麦粉对挂面品质的影响

选择荞麦粉为辅料,以挂面的咀嚼度为指标,研究荞麦粉和食品添加剂对挂面品质的影响。在单因素研究的基础上,通过正交试验和二次旋转分析,建立数学回归方程,确定荞麦挂面的的最佳工艺和配方。结果表明,荞麦挂面的最优配方为荞麦粉质量分数19%,CMC-Na 0.3%,六偏磷酸钠0.08%,在此条件下质构仪得出的挂面咀嚼度值为196.518。     

Phylogenetic analysis of AGAMOUS sequences reveals the origin of the diploid and tetraploid forms of self-pollinating wild buckwheat,Fagopyrum homotropicum Ohnishi

Fagopyrum homotropicum Ohnishi is a self-pollinating wild buckwheat species indigenous to eastern Tibet and the Yunnan and Sichuan Provinces of China. It is useful breeding material for shifting cultivated buckwheat (F. esculentum ssp. esculentum Moench) from out-crossing to self-pollinating. Despite its importance as a genetic resource in buckwheat breeding, the genetic variation of F. homotropicum is poorly understood. In this study, we investigated the genetic variation and phylogenetic relationships of the diploid and tetraploid forms of F. homotropicum based on the nucleotide sequences of a nuclear gene, AGAMOUS (AG). Neighbor-joining analysis revealed that representative individuals clustered into three large groups (Group I, II and III). Each group contained diploid and tetraploid forms of F. homotropicum. We identified tetraploid plants that had two diverged AG sequences; one belonging to Group I and the other belonging to Group II, or one belonging to Group II and the other belonging to Group III. These results suggest that the tetraploid form originated from at least two hybridization events between deeply differentiated diploids. The results also imply that the genetic diversity contributed by tetraploidization of differentiated diploids may have allowed the distribution range of F. homotropicum to expand to the northern areas of China.     

Genetic analyses of agronomic traits in Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.)

The consumption of products made from Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) has increased in recent years in Japan. Increased consumer demand has led to recognition of the need for early varieties of this crop with high and stable yields. In order to accomplish this, more information is needed on the genetic mechanisms affecting earliness and yield. We conducted genetic analysis of 3 agronomic traits (days to flowering, plant height and total seed weight per plant) to segregate F₂ and F₃ populations derived from a cross between Tartary buckwheat cultivars ‘Hokuriku No. 4’ and ‘Ishisoba’. Broad-sense heritability estimates for days to flowering, plant height and total seed weight were 0.70, 0.62 and 0.75, respectively, in F₃ population. Narrow-sense heritability for total seed weight (0.51) was highest, followed by heritability for days to flowering (0.37), with heritability for plant height (0.26) lowest. Later flowering was associated with increased plant height and higher yields. From the F₄ generation, we identified twelve candidate plants with earlier maturity and reduced plant height compared to ‘Hokuriku No. 4’, but almost the same total seed weight. These results suggest that hybridization breeding using the single seed descent (SSD) method is an effective approach for improving agronomic characteristics of Tartary buckwheat.     

Traits of shattering resistant buckwheat ‘W/SK86GF’

Seed shattering is a significant problem with buckwheat, especially at harvesting time. Several reports have shown that a green-flower mutant of buckwheat, such as W/SK86GF, has a strong pedicel. Although a strong pedicel may provide some resistance to shattering in the field, no study has thoroughly examined this issue. In this paper, we demonstrate that a W/SK86GF has shattering resistance by comparing the degrees of shattering of W/SK86GF and Kitawasesoba (leading variety of Hokkaido with non-green-flower traits) through a test for four years, including a typhoon hit year in the field. In a non-typhoon year, the shattering seed ratio (shattering seed weight/(yield + shattering seed weight) × 100) of W/SK86GF at maturing time +15 days (+15D) was lower than that of Kitawasesoba. In a typhoon hit year, the shattering seed ratios of Kitawasesoba at maturing time and +15D were surprisingly high, 14.4 and 21.1%, respectively. On the other hand, those of W/SK86GF were only 3.08% and 2.57%, respectively; indicating W/SK86GF is promising as a shattering resistant line even in a typhoon hit year. From these results, shattering resistance of W/SK86GF can be evaluated after maturing time such as +15D and pedicel strength would confer W/SK86GF a shattering resistant trait.     

苦荞杂交F2 代的植物学性状表型研究

以栽培苦荞和苦荞近缘野生种为亲本进行杂交,获得杂交后代并在F2代观察其性状分离比例.结果表明:栽培苦荞与苦荞近缘野生种杂交的F2代在花色、花序(小花疏密度)、茎色、分枝、叶形、叶色、瘦果表面有无刺、株型和落粒性等方面表现出性状分离现象,其中瘦果表面有无刺和种子落粒性性状的分离比例为9∶7,株型松散性状和分枝长短性状的分离比例为3∶1,通过X2测验,分别符合9∶7和3∶1的比例.其他各性状的分离比例尚不能确定.     

苦荞泡酒的工艺条件

以苦养麸皮为原料,用白酒浸泡,探究苦荞麸皮中黄酮溶入白酒的最佳条件和感官评价。通过不同固液比、酒度和时间进行单因素试验,确定各单因素在苦荞麸皮泡酒中黄酮溶入的较适宜范围,再通过正交试验确定出黄酮溶入的最佳条件,并对各产品进行感官评价。结果表明,影响黄酮溶入的主次关系为酒度>时间>固液比;当酒度为60%,时间为5 h,固液比为1:25时,白酒中溶入黄酮含量最高为3%;其产品感官评价均良好。     

Varietal Differences of Flood Tolerance during Germination and Selection of the Tolerant Lines in Common Buckwheat

Abstract

We evaluated the varietal difference in the flood tolerance of germinated seed in 17 Japanese varieties of common buckwheat (Fagopyrum esculentum Moench), including both local varieties and bred varieties or lines of different agroecotypes. Germinated seeds were flooded for 1 day in a growth chamber in June, July and August. The mean rate of seedling emergence from the seeds sown on different dates varied with the variety ranging from 20.4 to 57.4%. The mean emergence rate of summer agroecotypes (29.9%) was significantly lower than that of intermediate and late-summer agroecotypes (42.8 and 40.1%, respectively), and that of local varieties (44.2%) was significantly higher than that of bred varieties or lines (31.2%). These results suggest that inherent variation in flood tolerance was decreased by breeding as a result of a bottleneck effect. The local variety ‘Kitou zairai’, which exhibited a high and stable seedling emergence rate, may be a suitable choice in breeding for flood tolerance during germination. We also attempted to select for flood tolerance under mild selection pressure. Mass selection after four generations increased seedling emergence rate in five of six selected lines (with the exception of ‘Kitawasesoba’) compared with those of unselected populations, although the results varied with the line. These results indicate the possibility of breeding for flood tolerance during the germination period.     

Association of Grain Shedding Habit with Polyploidy in Tartary Buckwheat (Fagopyrum tataricum) Strains

Abstract

Sixty tartary buckwheat (Fagopyrum tataricum) strains were investigated for grain shedding habit, plant height, grain yield, dry weight of plant, weight of grain, days to flowering after sowing and DNA content of nuclei. The grain shedding habit was evaluated from the breaking strength of pedicel and the percentage of the grains dropped by threshing. DNA content of nuclei was detected by flow cytometry to classify the polyploidy level. The fluorescence intensity of the flow cytometry demonstrated no difference between common buckwheat (F. esculentum) and tartary buckwheat, but a clear difference was detected between the diploid and the autotetraploid strains. The survey of DNA content of the 60 tartary buckwheat strains revealed that most of the strains were diploids, but one strain was autotetraploid. The autotetraploid strain exhibited less grain shedding, and produced the largest grains among the strains tested. However, the other characters of the autotetraploid strain, such as plant height, grain yield, dry weight of a plant, and days to flowering, were similar to the mode of the traits of the diploid strains.