. 1999. Inheritance of self-compatibility and flower morphology in an inter-specific buckwheat hybrid. Can. J. Plant Sci. 79: 483-490. This study was conducted to determine the inheritance of selfcompatibility and homomorphic flower type when the wild species Fagopyrum homotropicum was crossed with common buckwheat (F. esculentum). Unidirectional interspecific hybrids between cultivated F. esculentum Moench. (common buckwheat) and its wild relative F. homotropicum were produced after controlled pollination and embryo rescue culture. Cross-compatibility was found to be better when thrum-type common buckwheat was used as the female parent rather than the pin-type. The resulting F 1 plants were partially fertile, late maturing and intermediate between the parents in flower shape and plant height. They segregated into heterostylic (thrum only) and homostylic types in equal numbers, indicating that homostyly is controlled by a single dominant gene. The thrum-type F 1 hybrids were backcrossed to common buckwheat and the progenies were raised utilizing embryo rescue culture. The homostylic F 1 hybrids were advanced to the F 2 and F 3 generations through self-fertilization and utilized, together with the BC 1 F 1 , for the analysis of the stylar genes. The results obtained indicate that the genes coding for heterostyly and homostyly are controlled by the multiple allelic gene S. It appears that the pin/thrum complex in F. esculentum is governed by a single genetic locus S with two alleles S and s that control the reaction in Ss (thrum-type) as well as the ss (pin-type) plants, respectively. The homomorphic flower type of F. homotropicum is governed by the allele S h. . These genes can be characterized by a relationship of dominance, i.e. S > S h > s. The introgression of F. homotropicum genes into common buckwheat was verified by means of electrophoretic analysis of seed proteins.

No abstract

. 1999. Isolation of protoplasts from viable egg cells of common buckwheat (Fagopyrum esculentum Moench.). Can. J. Plant Sci. 79: 593-595. In vitro fertilization could be useful to overcome the problem of self-incompatibility of common buckwheat. Therefore, experiments were conducted to isolate viable protoplasts from egg cells for use in vitro fertilization. Protoplasts from viable egg cells of common buckwheat were isolated by enzyme treatment followed by mechanical isolation. Incubation of ovules for up to 4 h allowed the boundary wall of the egg cells to become partially digested and the protoplasts of the egg cells came out of the micropylar or chalazal end after squashing with a mean isolation frequency of approximately 30% (6 out of 20 ovules). The egg cell protoplasts were larger than those of the synergids.

No abstract