Hybridization and self-compatibility in Celtis: AFLP analysis of controlled crosses

Abstract

Artificial cross-pollinations were carried out among seven species of Celtis L. (C. bungeana Blume, C. koraiensis Nakai, C. laevigata Willd., C. occidentalis L., C. reticulata Torr., C. sinensis Pers., and C. tenuifolia Nutt.) to test the potential for interspecific hybridization in Celtis breeding. AFLP profiles were used to assess the ancestry of progeny. Hybrids formed very rarely among these seven species of Celtis: only two interspecific hybrids were obtained. Self-pollination occurred occasionally in non-emasculated trees. AFLP analysis yielded false paternal markers at a very low frequency, likely due to DNA methylation differences. Plants with unexpected paternal markers were confidently distinguished from hybrids by calculating the probability of obtaining the observed number of paternal markers by chance. The study clearly demonstrated the importance of using large numbers of markers.