Cytogenetic studies on diploid and autotetraploid common buckwheat and their autotriploid and trisomics

Crossing autotetraploid plants with diploid parent is an efficient way to produce autotriploid and trisomics. Comparative studies on cytogenetics and pollen fertility in diploid and autotetraploid common buckwheat (Fagopyrum esculentum Moench) and their autotriploid hybrids and trisomics were conducted. Observation of meiosis metaphase I of pollen mother cells showed that the average configurations of chromosome pairing in the autotetraploid cultivar Emka, its inbreeding line Emka-1, and autotriploid hybrids were 0.67I + 11.60II + 0.32III + 1.79IV, 0.71I + 7.42II + 1.19 III + 3.22IV, and 4.71I + 4.71II + 3.29III, respectively. The average numbers of micronuclei in telophase II cells in the diploid cultivar Siva, autotetraploids Emka and Emka-1, and the autotriploid hybrids were 0.03, 0.09, 0.20, and 0.86, respectively. Siva had the highest pollen fertility (98.89%), followed by the autotetraploids Emka and Emka-1 (95.33 and 93.33%); the autotriploid hybrids had the lowest (31.28%). When autotriploid hybrids were backcrossed with diploid cultivar Sobano, 27.72% of the flowers pollinated yielded shriveled dead seeds, and only 3.08% yielded normal seeds. Of the 34 achenes of the autotriploid hybrids, 6 were double trisomics (2n + 2), 23 trisomics (2n + 1) and 5 diploids (2n). The segregation of short-style (Ss) and long-style (ss) plants in backcrossing progenies of trisomics showed that the S gene of common buckwheat was located on chromosome 4E. The common buckwheat trisomic lines produced in this study will become an important tool for common buckwheat genetics and breeding.