Cytogenetic Studies in Artificially Raised Interspecific Hybrids of Papaver
VII. P. somniferum L.×P. bracteata Lindl
1937 Volume 8 Issue 2 Pages 331-342
Details
1937 Volume 8 Issue 2 Pages 331-342
1. Hybrids between P. somniferum and P braeteata were produced, the former being used as female parent. The F1 plant appeared intermediate with respect to several characters, though with some matroclinic tendencies.
2. Some characters (laciniate petals, hairy peduncles, duration of life etc.) of P. somnif erum which are recessive in the F1 plants of somniferum×orientale, were found to be dominant in the F1 plants, of sonniferum×braeteata. In relation to this faet the cumulative effect of genes is discussed.
3. The number of the somatic chromosomes in the F1 plant is 18, i.e. the sum of the haploid chromosome numbers of both parents (11 and 7). 4 bivalents and 10 univalents- were observed in the diaphase of the PMC. This fast is in conformity with the view that the haploid chromosome constitution of P. somniferum is 4II+3I and that there are no homologous chromosomes between P. somniferum and P. braeteata.
4. The chromosome behaviour in the meiotic phases of the PMC of the F1 plant is very irregular, espeeially that of the univalent chromosomes. In different anthers different kinds of irregularities in chromosome behaviour were found. In some anthers there were observed many PMCs, in each of them all the separated halves of the bivalents, or some of them, formed a small nucleus, and the remaining chromosomes formed a large nucleus after the ist meiotic division. The temperature effect of the season an the meiotic division is suggested.
5. In the interphase nuelei in some PMCs, the 4 ehromatids in each of separated halves of bivalents and each of unseparated univalents and 2 chromatids in each separated univalent were clearly observed. The individual chromatids coiled spirally and twisted around each other. They may separate from each other in the first nuclear division of the pollen grains. In some of the chromosomes which consist of two pairs, of chromatids, chiasmata were observed. Here I wish to express my best thanks to Hon. Prof. K. FUJII, for his valuahle advice throughout the course of these studies. The expense of carrying out the present work was partly defrayed out of a grant from the Japan Society for the Promotion of S.cientific Research, to which my thanks are due.
