Chromosome doubling in Paspalum notatum var. saure (cultivar Pensacola)

Roberto Luis Weiler,Carine Simioni,Divanilde Guerra,Karine Cristina Krycki,Miguel Dall'Agnol

doi:10.1590/1984-70332015v15n2n19

Abstract

Paspalum notatum is one of the most important native grassland species of southern Brazil, and the main forage source for livestock. The native ecotypes are tetraploid and have apomictic reproduction, which prevents the registration and protection of plant varieties. However, the cultivated variety Paspalum notatum var. saurae (cultivar Pensacola) is diploid and sexual. The objective of this study was to artificially produce polyploid cv. Pensacola plants, to be used as female parents in crosses with male tetraploid and apomictic parents. Seedlings and seeds were immersed in colchicine solutions for different periods. A tetraploid chromosome number was confirmed in three plants. The reproduction mode of the resulting polyploid plants will be assessed; if confirmed to be sexual, they can be used in crosses with native apomictic plants to breed new intraspecific hybrids.

Highlights

The grasslands Campos Sulinos are natural ecosystems with high biodiversity and have been the main forage source of livestock
A tetraploid chromosome number was confirmed in three plants
In the genus Paspalum, the ploidy level and reproduction mode are closely correlated; diploidy is correlated with sexual reproduction and alogamy and polyploidy is correlated with apomixis (Adamowski et al 2005)

Summary

Introduction

The grasslands Campos Sulinos are natural ecosystems with high biodiversity and have been the main forage source of livestock. The original cover with grasslands of more than half of the Campos surface in the state of Rio Grande do Sul was substituted by other vegetation types, without a proper evaluation of the forage potential. Most biotypes of P. notatum are autotetraploids (2n=4X=40) and are reproduced by aposporious apomixis (pseudogamy) (Forbes and Burton 1961). Most apomictic tetraploid species have, sexual conspecific, diploid and self-incompatible partners (Quarin and Norrmann 1990). The diploid (2n = 2x = 20) variety Pensacola grass The diploid form reproduces sexually by regular meiosis and is alogamous in view of its self-incompatibility system

Objectives

Methods

Results