Newly discovered tetraploid Fagopyrum homotropicum in Tibet, China

A cryptic species of Fagopyrum (Polygonaceae), F. homotropicum, is described and illustrated from Mangkang county, Tibet, China. F. homotropicum was firstly discovered in the 90’s, being to be diploid and characterized being a self-pollinating taxon. Detailed information of F. homotropiucm was rarely reported. In this paper, we summarized the morphological and karyological characters of tetraploid form F. homotropiucm (2n=4x=32), it is self-pollinating, and morphology indistinguishable in comparison from the diploid form.

Morphology of flower and development of male reproductive sphere of plants Fagopyrum homotropicum Ohnishi

Вид гречихи Fagopyrum homotropicum Ohnishi стал известен научной общественности в 1995 году. Благодаря своей скрещиваемости с культурными видами гречихи он был включен в разнообразные селекционно-генетические программы исследований. При этом многие аспекты его репродуктивной биологии, в частности эмбриологические особенности, остаются на данный момент неизученными. Настоящая работа посвящена изучению морфологии цветка и процессов формирования мужской репродуктивной сферы растений F. homotropicum. В результате проведенных исследований показано, что цветок F. homotropicum представлен 9 различными вариантами строения по количеству органов. Типичный вариант строения P5A8G(3) встречался с частотой 93,4%. Варианты P5A6G(3), P5A7G(3), P5A8G(0), P6A8G(3) зафиксированы с частотой 1,0-2,2%. Цветки нетипичного строения F. homotropicum обычно имеют измененное количество органов андроцея или гинецея. Полиморфизм строения цветков, таким образом, характерен для всех видов cymosum группы. Процессы микроспорогенеза и микрогаметогенеза протекают у F. homotropicum аналогично тому, как они описаны для других изученных видов Fagopyrum. Количество материнских клеток микроспор в гнезде пыльника составило 5,2±0,15. Обнаружены также нарушения в ходе эмбриологических процессов: приостановка развития клеток спорогенной ткани с последующей ее дегенерацией. Контрастные погодные условия в период формирования пыльцы не оказали влияния на ее фертильность: в разные годы она составила 93,4 и 93,6%. The species of buckwheat Fagopyrum homotropicum Ohnishi became known to the scientific community in 1995. Due to its crossbreeding with the cultural species of buckwheat, it was included into several breeding and genetic research programs. At the same time, many aspects of its reproductive biology, in particular embryological features, remain unknown at the moment. The present work is aimed to the study of flower morphology and the processes of formation of the male reproductive sphere of the F. homotropicum plants. Here we show that the flowers F. homotropicum are represented by 9 different variants of the structure by the number of organs. A typical variant of the structure P5A8G(3) met with a frequency of 93,4 %. The variants P5A6G(3), P5A7G(3), P5A8G(0), P6A8G(3) are recorded with a frequency of 1,0-2,2 %. The flowers of the atypical structure of F. homotropicum usually have an altered number of androecium or gynaecium organs. Polymorphism of the structure of flowers, thus, is characteristic of all species of cymosum group. The processes of microsporogenesis and microgametogenesis take place in F. homotropicum in the same way as they were described for other studied Fagopyrum species. The number of microspore mother cells in the anther nest was 5,2 ± 0,15. Abnormalities were also found in embryological processes: the suspension of the development of cells of sporogenic tissue, followed by its degeneration. Contrast weather conditions during the pollen formation did not affect its fertility: in different years, it amounted to 93,4 and 93,6 %.

Effect of storage temperature on occurrence of secondary dormancy in buckwheat seeds

Buckwheat (Fagopyrum spp.) is an important crop in many parts of the world, and many varieties have been developed. One of the important breeding issues to be addressed is the low resistance to preharvest-sprouting which causes loss in yields and quality of buckwheat grain. The occurrence of dormancy in cultivated buckwheat, including presence of secondary dormancy has yet to be clarified. In this study, we investigated the effects of storage temperature and periods using nine common buckwheat (Fagopyrum esculentum), seven Tartary buckwheat (Fagopyrum tataricum) and one wild buckwheat (Fagopyrum homotropicum). In some Tartary buckwheats stored at 5°C, the germination of seeds stored 10 days harvest was significantly less than the germination of seeds collected and sown at harvest maturity; the germination of other germplasm, including common buckwheat, was not affected by storage. This result indicates that Tartary buckwheat can acquire secondary dormancy. In addition, the wild buckwheat did not germinate at any storage temperature up to 30 days after harvest maturity; therefore, this buckwheat is considered to be promising breeding material for increasing resistance to preharvest-sprouting resistance.

Buckwheat Breeding. Past, Present and Future / Žlahtnjenje ajde v preteklosti, sedanjosti in prihodnosti

Buckwheat crop improvement by breeding has been taking place over the past 100 years or more. During this time there has been improvements in many desirable agronomic characteristics which has resulted in higher yields in many of the breeding programs. Phenotypic modifications, such as dwarf, semi-dwarf and branching have been reported. There has also been an effort to increase flower number as this has been shown in cross pollinating buckwheat, to increase yields. Flower cluster modifications and their effects on yield have also been studied. Increased reports on the discovery of buckwheat wild species have been reported from several programs with many interspecific crosses having taken place. Several of these crosses were performed with Fagopyrum esculentum in efforts to increase variability which can be used to increase yield potential as well as to obtain increased nutritional components. More recent efforts have focused on the development of self-pollinating buckwheat, both from introgression of genes from Fagopyrum homotropicum as well as from mutations in cross pollinating buckwheat. The main problem has been in breeding depression which has occurred in many of the reported attempts. However, high yielding homomorphic, self-pollinating varieties have been developed and are now in commercial production. There is now emphasis being placed on many of the nutritional aspects of buckwheat flour as well as value added components. It is expected that this will increase over time. Key words: Buckwheat breeding, homomorphic, autogamous buckwheat. Izvleček Žlahtnjenje ajde poteka že več kot 100 let. V tem času je bila dosežena izboljšava željenih agronomskih lastnosti, kar je pri mnogih programih žlahtnjenja omogočilo večje pridelke. Raziskovalci poročajo o fenotipskih modifikacijah, kot je pritlikava ali pol-pritlikava rast in razvejanje. Za povečanje pridelka so bile raziskane modifikacije socvetij. Število poročil o odkritjih divjih sorodnikov ajde in o mnogih medvrstnih križanjih se je v zadnjem času povečalo. V mnoga od teh križanj je bila vključena navadna ajda (Fagopyrum esculentum), da bi povečali variabilnost, kar bi lahko omogočilo povečanje pridelka in izboljšanje prehranskih lastnosti. Novejša prizadevanja so se osredotočila na razvoj samooplodnosti pri ajdi, z vključitvijo genov vrste Fagopyrum homotropicum, kot tudi mutacij pri ajdi, ki se je opraševala navzkrižno. Pri tem je bila glavna težava preseči depresijo zaradi samooploditev, depresija se je pojavila pri večih poskusih samooploditve. Ne glede na to je uspelo dobiti visokorodne homomorfne samooplodne sorte za ponudbo na trgu semen. Sedaj se prizadevanja usmerjajo k izboljšanju prehranske vrednosti ajde in pomembnih sestavin v ajdovi moki. Pričakovati je, da se bo pomen prehranske vrednosti ajde sčasoma še povečeval. Ključne besede: žlahtnjenje ajde, homomorfnost, samo­oplodna ajda

Amplified fragment length polymorphism linkage analysis of common buckwheat (Fagopyrum esculentum) and its wild self-pollinated relative Fagopyrum homotropicum

Common buckwheat (Fagopyrum esculentum) (2n = 2x = 16) and Fagopyrum homotropicum (2n = 2x = 16) were mated in an interspecific cross and amplified fragment length polymorphism (AFLP) linkage maps were constructed by analyzing segregation in the F2 population. Six hundred and sixty-nine bands were identified using 20 AFLP primer combinations, of which 462 (69%) segregated in the F2 population. The map of F. esculentum has eight linkage groups with 223 markers covering a total of 508.3 cM. The map of F. homotropicum has eight linkage groups with 211 markers covering 548.9 cM. There was one to one correspondence of the esculentum and homotropicum linkage groups. Three morphological markers, distylous self-incompatibility, shattering habit, and winged seed, were located on the AFLP map. Distylous self-incompatibility and shattering habit are tightly linked to each other (1.3 cM) and are located near the center of linkage group 1. Winged seed is located on linkage group 4. Key words: common buckwheat, AFLP, linkage analysis, distylous self-incompatibility, shattering habit.