Morphology and fertility of a spontaneous octoploid of white clover [Trifolium repens L.]

In the progeny of a hybrid obtained after crossing local Polish and local Bulgarian white clover genotypes one octoploid (2n=64) plant was selected. In view of difficulties to obtain seeds, the octoploid plant was vegetatively propagated. The progeny of the octoploid obtained as a result of self- and cross-pollination of cloned plants was examined and compared to related tetraploids with respect to morphological characters, fertility and embryo sac structure. Vegetative and generative organs of the octoploid were slightly larger than those of tetraploids. The number of flowers per head was larger in the octoploid than in tetraploid plants. The spontaneous octoploid appeared to have a low fertility after both cross- and self- pollination. It was most probably caused by low pollen viability, by decline of megasporocyte and megagametocyte in the process of ontogenesis and by a smaller ovule number per ovary. Seeds of octoploids were partially underdeveloped and only 23.85% of them gave rise to seedlings

Badania mieszańców w rodzaju Trifolium L. IV. Cytogenetyka mieszańca Trifolium repens L. × T. isthomocarpum Brot. [Investigations on hybrids of the genus Trifolium L. P. IV. Cytogenetics of the cross T. repens L. × T. isthomocarpum Brot.]

Interspecific F1 hybrid between Trifolium repens (2n = 32) and T. isthomocarpum (2n = 16) was obtained. The hybrid is sterile and its disturbed meiotic divisions are described. It is suggested from cytogenetic evidence that one of the genomes of T. repens is similar to the genome of T. isthomacarpum

Cytoembryology of infertile segregants of the hybrid Lupinus varius L. x L. digitatus Forsk

In F₂, F₃ and F₄ generations of one hybrid line of Lupinus varius × L. digitatus, segregation into infertile and fertile plants in the ratio 3:1 was observed. Cytoembryological analyses showed that sterility was caused by irregularities in megasporocyte formation, in megasporogenesis and megagametogenesis. The following abnormalities lead to female sterility: no megasporogenic cells separated in nucelluses; in other nucelluses with megaspore mother cells, these cells underwent vacuolation and died before reduction division. In the megaspore mother cells, in which probably meiosis occurs, the megasporocyte division is irregular; a restitution nucleus is frequently formed after reduction division and such megasporocyte develops into an embryo sac. In 8-nucleate embryo sacs a change in the nucellus polarization was observed, while in rarely encountered embryo sacs the embryo cells underwent vacuolation and then died. Female sterility in the studied segregants is determined genetically, whereas sterilization of reproduction cells is a developing process throughout the period of sporocyte and female gametophyte formation

Inheritance and cytogenetics of sterility in yellow lupin (Lupinus luteus L.)

Amon g the hybrids of the cultivated form named 'Batavo', originating from Holland, and 6 primitive forms of the yellow lupin was one hybrid combination found (Batavo X primitive No. 5), which in F2 and F3 gives fertile and sterile plants with the ratio 3 : 1. The gene causing sterility was appeased as a result of crossing over at the time of prophase of meiosis in the sporogenic cells of F1 plants. This gene in homozygotic condition in F2 and F3 plants causes the coalescence of chromosomes, disturbances in the process of meiosis and microsporogenesis what leads to forms with non viable microspores. The sterile plants blossom abundantly but they give not pods and seeds

Inheritance of changes conditioned by the leaf-reducing gene in Swedish clover (Tnfolium hybridum L.)

A description of a new mutant of Trifolium hybridum with reduced leaf blades is given. The mutants are female sterile due to deficient ovary development. The genetic analysis showed that morphological changes and lowered fertility are caused by one recessive allele of the gene called reductivus. Male infertility in B1 plants depends also on one recessive gene, but located on a different chromosome than is the reductivus gene

Iivestigations on hybrids in the genus Trifolium L. V. Fertility and cytogenetics of the hybrid Trifolium nigrescences Viv. x T. isthomocarpum Brot.

T.nigrescens (2n = 16) crosses with T .isthomocarpum (2n = 16) reciprocally. The viability of hybrid seedlings depend from the direction of the cross. At the time of diakinesis and metaphase I the average chromosome figures per PMC's was 7.014II, 0.005III, 0.435IV and 0.209I. For one half of the PMC's in the metaphase I the typical chromosome arrangement was 8II. The F1 plants was almost completly sterile. The causes of viability of hybrid seedlings depending on the direction of the cross, and the sterility of hybrid plants, are discussed