Interspecific hybridization in Cucumis L. II. The crossability of species,an investigation of in vivo pollen tube growth and seed set

Summary The crossability of 12 Cucumis species of African and Asiatic origin was studied in a diallel cross, in order to find ways to realise the cross between the common cucumber (C. sativus L.) and its wild relatives which carry resistances against diseases and pests.Self-pollinations and cross-pollinations within species gave normal pollen tube growth and seet set. The different accessions within a species, as a rule reacted alike in interspecific crosses. In crosses between African species different crossing patterns were found, viz. bilateral congruity, bilateral incongruity and unilateral incongruity. Within C. sativus all accessions intercrossed freely, except one, which displayed unilateral incongruity.Good seed was harvested from several crosses and in some cases embryo culture was needed for further development of seeds. No good seeds were obtained from any cross between a species of the African group and C. sativus L.