Chromosome numbers and pollen stainability of three species of Pacific Island breadfruit (Artocarpus, Moraceae).

Chromosome numbers were determined for 48 accessions of breadfruit (Artocarpus altilis, A. mariannensis, and A. camansi [Moraceae]) from 16 Pacific Island groups, Indonesia, and the Philippines. Artocarpus camansi and A. mariannensis exhibit counts of 2n = 56; 2n = 56 (diploidy) and 2n = 84 (triploidy) were observed for A. altilis. Most diploid cultivars of A. altilis were seeded, but two cultivars with reduced seed number were observed. Micronesian accessions included putative interspecific hybrids between A. altilis and A. mariannensis. The majority of these accessions were seedless diploids, but triploid putative hybrids were also observed. Pollen stainablility was shown to correlate with the degree of seediness.