Bahiagrass Tetraploid Germplasm: Reproductive and Agronomic Characterization of Segregating Progeny

Abstract

The tetraploid germplasm of bahiagrass, Paspalum notatum Flüggé, is an unexploited source of variability that can be used for the genetic improvement of this species as forage or turf. The objectives of this research were to develop a segregating population by hybridizing induced sexual and apomictic clones and to characterize the resulting population for mode of reproduction, seed fertility, growth habit, seasonal growth pattern, and frost resistance. A population of 591 hybrids had a 4:1 ratio between sexual and apomictic (facultative + obligate apomictic) plants and an 8:1 ratio between others (facultative apomictic + sexual) and obligate apomictic plants. The general fertility of the progeny was higher than that of the induced sexual parents. Significant differences were observed for self‐ and cross‐fertility among apomictic progeny and for self‐fertility among sexual progeny. Most sexual progeny set the same amount of seed when self‐ or cross‐ pollinated, indicating an absence of self‐incompatibility. Marked variation was observed for growth habit, seasonal growth patterns, and frost resistance among the progeny. Heritability estimates obtained for these characteristics indicate that selection can be successfully used for the genetic improvement of this species.

A reference floral transcriptome of sexual and apomictic Paspalum notatum

“…In fact, the use of apomixis is currently having direct consequences on the breeding of natural apomictic forage grasses of the Brachiaria [9–11] and Paspalum [12, 13] genera, allowing a significant increase in cattle production in tropical and sub-tropical areas of the Americas. However, major food crops such as maize, rice and wheat are not naturally apomictic and attempts to introduce the trait from wild relatives remain unsuccessful as yet [14, 15].…”

Determination of the mode of reproduction of bahiagrass hybrids using cytoembryological analysis and molecular markers

“…In "bahiagrass", apomixis is aposporic and pseudogamous, in which embryo sac arises by mitotic division of a somatic cell of the embryo sac and endosperm develops by the union of a male nucleus of the pollen grain with the polar nuclei (Acuña et al, 2009).…”

Forage performance of Paspalum hybrids from an interspecific cross

“…In this manner, they are able to reinitiate growth faster at the beginning of the warm season, thus decreasing the forage deficit period (COSTA et al, 2003). ACUÑA et al (2009) observed that the hybrids of P. notatum that showed greater TCold also demonstrated a greater capacity for re-growth. When considering all the forage traits of interest, the results demonstrated that although the tested progenies did not surpass the Azulão genotype in TDM production, the hybrids 08Q01 and 08Q44 stand out, particularly in production of LDM and TCold.…”

“…In each cut, it was counted the number of tillers (NT). Plant height (PH, cm plant -1 ) was measured from the soil to the average bending height of leaves in the canopy, whereas the plant coverage diameter (PCD, cm planta -1 ) was estimated using the average coverage diameter for each plant (ACUÑA et al, 2009;PEREIRA, 2013). Approximately five days after each cut, visual notes were made concerning new sprouts using a scale from 1 to 5, with 1 denoting lower re-growth ability and 5 indicating the best (PEREIRA, 2013).…”

“…Approximately five days after each cut, visual notes were made concerning new sprouts using a scale from 1 to 5, with 1 denoting lower re-growth ability and 5 indicating the best (PEREIRA, 2013). During the winter of the first year, on June 21 and July 26 2012, visual notes were made for the tolerance to cold (TCold) using a 1-5 scale, with 1 indicating lower tolerance and 5 the greatest (ACUÑA et al, 2009;PEREIRA, 2013 SCHWARZ, 1978), restricted likelihood algorithm (-2LMR), Mean Square Error (MSE). The best matrices were selected through the AIC and BIC criteria, and the likelihood test.…”