Studies on the Specie and genus crosses in Malvaceae (I) : The F<SUB>1</SUB> hybrid, Hibiscus mutabilis, L. x H. Moscheutos, L.

Abstract

1. The reciprocal crosses were madc between H. mutabilis and H. Moscheutos as the studies on the hybridization in species and genus crosses in Malvaceae and F1 seeds and plants Were obtained from H. mutabilisxH. Moscheutos. 2. The set % of pods in H. mutabilis X H. Moscheutos was 35. 26%, but that of pods having the viable seeds was 13. 16%, and the pod fertility, percentage of pods having the viable seeds per total pods, was 37. 31%The size of pods obtained in H, mutabilis X H. Moscheutos was smaller than that of the selfed mother, the shape of F1 seeds obtained resembled the mother plant, but its size was smaller. which was shrub. 3. The number of the viablc seeds per pod obtained in H. Mutabilis X H. Moscheutos was only 3. 3, but that in pods having the viable seeds was 8.8. The germination % of F1 sceds was 41.67%, showing the lower value than those of the parents. 4. The shape of cotyledons of F1 quite resembled the father plant, but its size was smaller. The shape of leaves of F1 was rather similar to the mother plant rcsembling the intermediate shape bctween the parcnts. The shape of flowers of F1 quite reselmbled the father plant, but its size was smaller, showing the. intenrrediate size of the plants. The colour of flowers of F1 was dark pink, but that of the mother plant was white, and of the father plant was light pink. The time of blooming of F1 in the first year of growth was later than the intermediate time of the parents, but that in the second year of growth was equal to the mothel plant, bloonrling earlier than the father plant. 5. In F1 the plant height was low showing the similarity to the mother plant at the early stage in the first ycar of growth, but elongated to the height of the father plant in the middle of October, and became at the end taller than those of the parents in the middle of October in the second year of growth. The thickness of stems of F1 was more than those of thc parents, and the numbers of leaves, nodes and branches were more nurnerous than thowe of the parents. The plant type of F1 was variou observing 9 types, and no individuals of the same type to the parents were obtained. The tissue of stems of F1 quite resembled to the mother plant which was shrub. 6. The pollen grains of F1 were of various sizes and almost all the pollcn grains were abortive, and the pelcentage of good pollen grains was O. 3%. Thet size of good pollen grains of F1 was larger than those of the parents. The number of pollen grainsper anther of F1 was more numcrous than those of the parents.