The Rate of Spontaneous Inbreeding of Trifoliate Orange and Some Characteristics of the Inbred Seedlings

Abstract

Isozyme of glutamate oxalacetate aminotransferase (GOT) in the trifoliate orange (Poncirus trifoliata Raf.) was analyzed. Locally collected mature trees had a typical genotype of MP and SM at Got-1 and Got-2 loci, respectively. Although the trifoliate is known as an apomict (nucellar polymbryony), some of the seedlings were homozygous at Got-1 and/or Got-2, and these were assumed to be inbred ones. Average height of the inbred seedlings was much lower than that of the apomicts. A part of the inbred seedlings flowered precociously. Some of the morphologically or physiologically distinctive strains, includin*" Iarge-ffowered strains, were assumed to arise from inbreeding of the trifoliate orange. Some differences in pollen morphology between inbred and apomict-propagated strains were observed with scanning electron microscopy.