Reproduction mode and apospory expressivity of selected hybrids of Paspalum notatum Flgge

Abstract

Paspalum notatum Flüggé (bahiagrass) is the most important forage grass in the native grasslands of southern Brazil; the native germplasm is tetraploid and apomictic. Breeding to produce cultivars has been possible due to chromosome doubling of sexual diploid accessions, allowing hybridizations with apomictic genotypes, generating progenies with variability for agronomic traits and segregating for reproduction mode. The aim of this study was to determine the reproduction mode of selected hybrids derived from intraspecific crosses through cytoembryological analysis and to evaluate the level of apospory expressivity. Eighty one tetraploid hybrids corresponding to 21 families of sexual and apomictic parents were generated and 28 most productive plants based on their superior agronomic performance in the field were evaluated. Sixteen hybrids were reproduced sexually and 12 of them were highly apomictic or facultative apomictic. Sexual hybrids may be used for further crosses in the breeding program while highly apomictic plants produce uniform progeny and become candidates of new cultivars to promote pasture diversification.

Seed yield and quality of Paspalum notatum Flügge intraspecific hybrids

“…Improving seed production in a native warm-season perennial grass such as bahiagrass is a challenge because similar to other tropical forages, this species presents non domesticated traits such as dehiscent seeds (Valle, Jank, & Resende, 2009). In this study, we evaluated seed production and seed quality in a group of tetraploid hybrids resulting from one cycle of crossing between native ecotypes from Rio Grande do Sul, Brazil, and artificially duplicated sexual diploids (Weiler et al, 2017;Machado et al, 2021). These tetraploid hybrids were compared with Pensacola, a sexual diploid cultivar, and V4 and Bagual, both native tetraploid and apomict ecotypes.…”

“…To date, intraspecific breeding efforts to improve forage traits have resulted in the selection of improved hybrids (Barbosa et al, 2019;Graminho et al, 2019) and the release of the cultivar Boyero (Urbani et al, 2017). The bahiagrass breeding program of the Federal University of Rio Grande do Sul (UFRGS) has explored tetraploid bahiagrass germplasm and reported improvements in forage production and nutritive value in native ecotypes and intraspecific hybrids (Fachinetto, Schneider, Hubber, & Dall'Agnol, 2012;Steiner et al, 2017;Machado et al, 2017;Machado, Krycki, Weiler, Simioni, & Dall'Agnol, 2021;Weiler et al, 2018;Barbosa et al, 2019;Graminho et al, 2019). Introduced species such as Urochloa spp.…”