抄録
In order to develop new geranium cultivars with characteristics not found in existing cultivars, such as heat tolerance and odorless leaves, intercrosses between geranium and four wild species of section Ciconium were carried out. The intercrosses between geranium and P. frutetorum, P. inquinans, and P. salmoneum showed relatively high compatibility, regardless of the seed parent. Their F1 plants grew vigorously and developed normally. On the contrary, some F1 plants derived from the intercross with P. acetosum developed chlorosis and variegation in the leaves, with many plants dying in the early stage of growth. However, the F1 plants that survived showed high pollen fertility, and F2 and BC1 generations could be obtained easily. Some F2 plants showed odorless, and all BC1 plants had non-trichome leaves. Heat tolerance trial was carried out in a greenhouse from spring to autumn using all plants of F1, F2 and BC1 obtained from backcrossing to geranium. Favorable plants with an increased number of flowering peduncles even in summer were selected from the BC1 plants derived from P. frutetorum, P. acetosum, and P. salmoneum. These progeny can be used as breeding material for producing promising new heat-tolerant geraniums with odorless leaves.
