Analysis of self-fertilization and meiotic behavior of eleven Brazilian triticale cultivars at two sowing dates

Divanilde Guerra,Marcelo Teixeira Pacheco,Luiz Carlos Federizzi

doi:10.1590/s1984-70332011000200003

Divanilde Guerra, Marcelo Teixeira Pacheco + Show 1 more

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https://doi.org/10.1590/s1984-70332011000200003

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Abstract

Eleven Brazilian hexaploid triticale cultivars (2n = 6x = 42), from three breeding programs, were evaluated for their ability of self-fertilization in 2006 and for meiotic behavior, meiotic index and pollen viability at two sowing dates in 2007. High potential of self-fertilization was observed, with values up to 89.52 %. Many irregularities were found in the meiotic analysis, such as the presence of univalents, laggard chromosomes and micronuclei in tetrads, which compromised both meiotic behavior and meiotic index. At the first sowing date, more suitable for normal plant development, overall mean values of 52.68 % for normal cells and 64.95 % for meiotic index were observed. At the second sowing date, less appropriate for the crop, overall means of 52.23 % for normal cells and 58.24 % for meiotic index were obtained. Despite all the irregularities, considerable pollen viability was observed, reaching overall means of 92.08 % and 91.07 % for the first and second sowing dates, respectively.

Highlights

In recent decades, intensive crossing has been conducted in the tribe Triticeae aimed at the production of intergeneric hybrids
This study was conducted at the Agronomic Experimental Station (AES) of the Federal University of Rio Grande do Sul (UFRGS), located in Eldorado do Sul, Rio Grande do Sul State (RS) - Brazil, and at the Laboratory of Plant Cytogenetics of the Department of Field Crops (Departamento de Plantas de Lavoura) of the Agronomy School (Faculdade de Agronomia) - Universidade Federal do Rio Grande do Sul (UFRGS)
In order to assess the fertility of Brazilian cultivars of triticale, through the ability to exclusively produce seeds by self-fertilization, a field experiment was established at the AES/UFRGS in 2006 with eleven triticale cultivars (Table 1)

Summary

Introduction

Intensive crossing has been conducted in the tribe Triticeae aimed at the production of intergeneric hybrids. The first man-made cereal, derived from hybridization between two species of different genera was obtained by the cross between wheat (Triticum spp.), as the maternal parent, and rye (Secale cereale), as the paternal parent, obtaining a hybrid called x Triticosecale Wittmack, commonly known as triticale, as widely used in the literature (Oettler 2005) This new allopolyploid may have different ploidy levels, being classified into three types: octaploid (2n = 8x = 56), hexaploid (primary and secondary) (2n = 6x = 42) and tetraploid (2n = 4x = 28) (Gupta and Baum 1986). Triticale has a tendency to allogamy and the percentage of crossfertilization seems to depend on the genotype and environmental conditions (Oettler 2005, Carvalho et al 2008)

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