Mode of Reproduction of Colchicine‐Induced Paspalum plicatulum Tetraploids

Abstract

Paspalum plicatulum Michx. is a wild forage grass species. The common races are tetraploid and apomictic, while sexual diploid representatives have been reported sporadically. Objectives of this study were to induce sexual 4x individuals from sexual diploids, determine the capacity for hybridization with other apomictic 4x species closely related with P. plicatulum, and thus create a tetraploid sexual material cross compatible with apomictic 4x species of the Plicatula group of Paspalum. Two induced tetraploid plants were recovered from germinating 2x seeds treated for 24 h with colchicine. Bivalent and quadrivalent chromosomes were the most common association at meiosis in these autotetraploids. Embryological analysis and progeny tests using molecular markers revealed that both induced tetraploids reproduced sexually. Single‐seed screening by flow cytometry confirmed full sexual reproduction. These plants retained the high self‐incompatibility system of the diploids, but set seed after reciprocal crosses and when crossed with pollen of apomictic 4x P. guenoarum Arechav. of the Plicatula group. Both sexual 4x plants constitute the foundational material for plant improvement through gene exchange and selection in apomictic 4x P. plicatulum and possibly in several apomictic species of the Plicatula group.

Variabilidade genética de caracteres forrageiros em Paspalum

“…A descoberta de plantas diploides sexuais em populações naturais de P. plicatulum possibilitou a obtenção de novos genótipos a partir de cruzamentos com espécies compatíveis (Sartor et al, 2009 A precipitação média é de 1.600 mm, e a temperatura média é de 21,8ºC. Janeiro e fevereiro são os meses mais quentes do ano, com temperatura superior a 22ºC, enquanto junho e julho são os meses mais frios, com temperatura média entre 3 e 18ºC.…”

Forage characters of different Paspalum species in Rio Grande do Sul: a meta-analysis

“…The P. guenoarum ecotype 'Rojas' was used as the male parent, and the P. plicatulum sexual genotype 4c-4x was used as the female parent. The chromosomal set of the sexual genotype was duplicated with colchicine (SARTOR et al, 2009) to enable cross-breeding between the different species and promote the production of fertile offspring. Hybrids evaluated (H12, H13, H20, and H22) were selected for their higher TDMP, as described by PEREIRA et al (2015) and MOTTA et al (2017).…”

Genetic variability of the components of seed yield in interspecific hybrids of Paspalum

“…The discovery of sexually reproducing diploid plants in natural populations of Paspalum plicatulum made it possible to obtain new genotypes by crossbreeding with compatible species (Sartor et al, 2009), opening a vast array of possibilities in the genetic improvement of this species.…”