CHARACTERISTICS OF F₁ HYBRIDS PRODUCED BY OVULE-CULTURE IN ORNAMENTAL PELARGONIUM

Interspecific hybridization was carried out using ovule culture technique between show pelargonium (Pelargonium X domesticum Bailey) and some other Pelargonium species, with the intention of introducing some desirable characters into show pelargonium.
In diploid (2n=22) X tetraploid (2n=44) crosses, callus formation rates were generally low (3.1–6.5 %). In tetraploid X tetraploid crosses, however, the rates were either very high (80.0 %) or comparatively low (8.3 %) according to parental combinations.
Organ differentiation from calli occurred with ease in all cross combinations (67–100 %). The hybrids obtained were characterized as following types. (1) Ever-flowering type.
The flowering period of an F₁ hybrid between ‘Grand Slam’ and P. quercifolium was two times longer than that of ‘Grand Slam’. (2) Multiflorous type.
Triploid (2n=33) and hexaploid (2n=66) hybrids from the cross between ‘Prince Rupert’2x (2n=22) and ‘Strawberry Sundae’ (2n=44) produced many peduncles.
Hybrids between ‘Prince R.’4x (2n=44) and ‘Strawberry S.’ produced one to two times as many peduncles as ‘Strawberry S.’. With respect to flower colour, the hybrids in this cross showed a wide variation.
A hybrid between ‘Purple Butterfly’ (2n=22) and ‘Strawberry S.’ also showed more than twice as many peduncles and flowers as ‘Strawberry S.’. Besides the above hybrids, several multiflorous types were further found from other cross combinations. (3) Dwarfness.
Dwarf types were obtained from such cross combinations as ‘Prince R. ‘2x X ‘Strawberry S.’, ‘Mme.
Layal’ X ‘Grand S.’ and ‘Mme.
Layal’ X ‘Strawberry S.’.

In Vitro Culture, XXI IHC

M. KATO, S. TOKUMASU

https://doi.org/10.17660/ActaHortic.1983.131.28