Could the Dilatata group of Paspalum be bred as sexual species? A preliminary assessment

Abstract

AbstractPaspalum dilatatum Poir. is a perennial apomictic and pentaploid South American grass and a very valued forage crop. The species has been available commercially in several parts of the world; however, its low seed production, apomictic reproduction and ergot susceptibility are important limitations for its adoption and breeding. The Dilatata complex includes five sexual tetraploid mostly selfing species, very closely related to P. dilatatum, which can be hybridized in different combinations. To explore the productive potential of breeding this species group as a sexual selfing tetraploid by combining germplasm from different tetraploid sources, a cross was made between Paspalum flavescens and Paspalum plurinerve which showed high productivity and resistance to ergot. The F1 was compared to the parents and 20 F3 families to evaluate the presence of heterosis, and estimate the additive genetic variance and the degree of transgressive segregation for morphological and productive traits. The F1 showed heterosis for dry matter and the number of fertile tillers, while the F3 showed transgressive segregation in more than 30% of the families for most traits. These results show that hybridization at the tetraploid level can generate vigorous and productive recombinants with a high potential to produce promising transgressive segregants. This breeding strategy appears highly promising, supporting further research on the potential of interspecific hybridization in this group.