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An important breeding issue in buckwheat is to increase its resistance to lodging, which can result in the loss of yield and quality of buckwheat foods. We developed the semidwarf buckwheat 'Kyukei 50', which has a short plant height and a strong lodging resistance. The internode length of 'Kyukei 50' was shorter than that of the summer‐sown standard variety 'HITACHIAKISOBA'. Progeny analysis revealed that the semidwarf trait was dominated by at least one recessive gene. Compared with 'HITACHIAKISOBA', in 'Kyukei 50', the time of maturation was earlier, and the pre‐harvest sprouting resistance was the same, indicating that 'Kyukei 50' is suitable for sowing in both spring and summer. 'Kyukei 50' exhibits the 'green flower type' shattering resistance trait and, therefore, has a thick pedicel; breaking tensile strength is approximately two‐fold stronger than that of 'HITACHIAKISOBA'. The yield of 'Kyukei 50' is the same as that of 'HITACHIAKISOBA'. In addition, the lowest seed height of 'Kyukei 50' was >17 cm. These results indicate that the 'Kyukei 50' is a promising breeding line for lodging resistance and loss of harvesting machinery. [ABSTRACT FROM AUTHOR]

To evaluate the potential of perennial buckwheat (Fagopyrum cymosum; FC) as a food source, rutin concentration was investigated. FC contains more than 1% (w/w) rutin and 0.03% quercetin in the leaves, flowers, and seeds. In particular, rutin and quercetin concentrations were high in plant seeds. Therefore, FC is useful as a rutin- and quercetin-rich material. In contrast, the FC seed contained a large amount of rutinosidase. Purified rutinosidase in a homogenous mixture consisted of only one isozyme with M.W. of 58.4 KD and low Km for rutin (0.367 mM). The rutin concentration in the FC dough decreased to almost zero, 10 min after the addition of water. Parallel to the decrease in rutin, quercetin was increased, and strong bitterness was generated, whereas steam-heated flour in which rutinosidase was inactivated did not have rutin hydrolysis and bitterness. These results indicate that rutinosidase is a major cause of rutin hydrolysis and bitterness. The in vitro rutinosidase is inactivated at pH 8.0 and 65 °C. Therefore, the control of dough pH and temperature should be useful in preventing rutinosidase activity. [ABSTRACT FROM AUTHOR]

One of the important breeding issues in buckwheat is to increase resistance to preharvest sprouting, which can result in the loss of yield and quality of buckwheat food, especially in spring‐sown buckwheat. The preharvest‐sprouting resistance of self‐pollinating buckwheat in the summer ecotype is very weak. Therefore, we developed a self‐pollinating breeding line IHK1, which has strong preharvest‐sprouting‐resistance traits. IHK1 was developed by cross breeding between 'Kyukei37' (a preharvest‐sprouting‐resistant outcrossing line) and IH3 (a self‐pollinating summer‐ecotype line). Progeny analysis revealed that the preharvest‐sprouting resistance trait in IHK1 was dominant. In three field trials conducted over 2 years, the maturation time of IHK1 was the same as that of 'Harunoibuki', the leading spring‐sown variety in the Kyushu region and the plant was shorter than 'Harunoibuki'. The yield of IHK1 was approximately 70%–85% of that of 'Harunoibuki' (165 kg/10 a; average of three times cultivation), whereas it was approximately 258%–333% when compared with IH3. Thus, IHK1 is a promising breeding line for self‐pollinating buckwheat, especially spring‐sown buckwheat. [ABSTRACT FROM AUTHOR]

Buckwheat has open‐flower morphology; therefore, isolation is necessary to propagate even in self‐pollinating lines. Here, we developed a self‐pollinating closed flower breeding line 'CFK1' by crossing between closed‐flowering individual and self‐pollinating breeding line. Progeny analysis suggested that the closed‐flowering trait would be dominated by double recessive gene, which we named closed‐flowering A and B (cfA and cfB). The evaluation test of outcrossing rate in the field revealed that 'CFK1' had 0% in progeny. An a histochemical investigation of flower buds morphology using scanning electron microscope revealed that the petals of 'CFK1' were tightly adhered to other petals whereas completely separated in wild type. The agronomic characteristics were evaluated by performance test. Compared to leading variety 'Shinanonatsusoba', the 'CFK1' had lower plant height, total weight, grain yield and 1‐L weight whereas higher plant height, total weight, grain yield and 1‐L weight when compared to 'IH3'. The preharvest‐sprouting resistance of 'CFK1' is slightly stronger than that of other tested buckwheat. From these results, 'CFK1' is promising self‐pollinating breeding line that is resistant for outcrossing. [ABSTRACT FROM AUTHOR]