Japanese Journal of Crop Science

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F₁ plants of Quamoclit angulata × Q. pennata showed the intermediate states between the tow parents regarding the shapes of leaves and flowers. The characters of these F₁ plants, including the flower color, resembled but somewhat differed from those in Q. Sloteri which is said to have been derived from the cross between Q. coccinea and Q. penntata. Q. angulata used by us may be taxonomically comprised in Q. coccinea, or it is closely related to the latter. 109 individuals of our F₁ showed complete sterility. The chromosome number was observed in root tips to be 28 in angulata, 30 in pennata and 29 in F₁. About 13% of 962 pollen mother cells of F₁ formed dyad cells. Some of them may contain the somatic number of chromosomes, while others may possess irregular number owing to the uneven distribution of chromosomes. If the analogous process occurs in the female gametogenesis, diploid egg cells may be formed. And by the fertilization of diploid male and female gametes, F₂ plants showing 2n=58 will be formed, which will start as a new constant species. In such a way a species resembling Sloteri may probably be originated. F₁ plants of Q. coccinea, var. hederifolia × Q. pennata were intermadiate of the parents in the shapes of leaves and flowers. The difference in leaf shape and flower color between this F₁ and Sloteri was larger than that between F₁ of angulata × pennata and Sloteri. 7 individuals of this F₁ were also completely sterile. The chromosome number was counted in root tips to be 28 in coccinea, var. hederifolia and 29 in F₁ made between this and pennata. In this F₁ 4.7% of 558 pollen mother cells formed dyad cells, and regarding their chromosome contents the same may be said as was stated for the contents of dyad cells in F₁ of angulata × pennata. The possibility of the formation of a new fixed species showing 2n=58 may also be seen here. F₁ of Sloteri × pennata was also observed.

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