Interspecific Hybrid Dwarfism and Geographical Distribution of the Dwarfness Gene in Capsicum

Abstract

Some cultivars of Capsicum annuum show dwarfness in their interspecific hybrids with C. chinense ′No. 3341′. The dwarfness is represented by the termination of leaf differentiation after development of several leaves in both main and lateral shoots.
The dwarf plants generally maintain their growth characteristics for two years. The top/root ratio of the dwarf plants was smaller than in normal plants. Root growth of dwarf plants increased nearly to normal by grafting of normal plants on them.
Dwarfness was shown to be controlled by two complemantary dominant genes, one of which is homozygous in ′No. 3341′. Many of the old Japanese cultivars, and the local Korean and Chinese cultivars, had another gene and developed dwarfness in hybrids with ′No. 3341′. All cultivars collected from other Asian areas, the Subcontinent of India, and North and South America did not possess the dwarf gene complementary to the gene of ′No. 3341′, except for one cultivar from Guatemala.
There are two theories for the route of pepper introduction to Japan; one by Portuguese and another via Korea. The present genetical studies strongly suggest that some cultivars had been introduced from Korea to Japan.