Cytoembryological evaluation, meiotic behavior and pollen viability of Paspalum notatum tetraploidized plants

Karine Cristina Krycki,Carine Simioni,Miguel Dall'Agnol

doi:10.1590/1984-70332016v16n4a43

Karine Cristina Krycki, Carine Simioni + Show 1 more

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https://doi.org/10.1590/1984-70332016v16n4a43

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Abstract

Abstract This study evaluated the mode of reproduction, the meiotic behavior and the pollen viability of three tetraploid plants (2n=4x=40) originated from somatic chromosome duplication of Paspalum notatum plants. The plant WKS 3 changed the mode of reproduction after duplication and became apomictic. The plants WKS 63 and WKS 92 confirmed sexual mode of reproduction identical to that of the original genotype. The analyzed plants presented meiotic abnormalities related to tetraploidy, and the chromosome pairing were variable, but it did not hinder the meiotic products, which were characterized by regular tetrads and satisfactory pollen fertility, ranging from 88.7 to 95.7%. Results show that all plants are meiotically stable and that they can be used in intraspecific crosses in the breeding program of Paspalum notatum.

Highlights

The accelerated degradation of natural pastures of the state of Rio Grande do Sul has led to the loss of genetic diversity of forage species and of quality forage supply to cattle in the state (Macedo 2009)
Among the several forage species that form native pastures, Paspalum notatum Flugge stands out for having excellent forage value and for being present in all natural pastures of the state (Nabinger and Dall’Agnol 2008). The breeding of this species is an alternative to the use of old and/or exotic varieties, with the search of selected materials; they are eligible for registration at the Ministry of Agriculture, Livestock and Supply (MAPA) and subsequent seed commercialization
In the Paspalum genus, there is close correlation between ploidy level and mode of reproduction; diploidy is correlated with sexual reproduction, and allogamy and tetraploidy are correlated with apomixis (Quarin 1992)

Summary

Introduction

The accelerated degradation of natural pastures of the state of Rio Grande do Sul has led to the loss of genetic diversity of forage species and of quality forage supply to cattle in the state (Macedo 2009). Among the several forage species that form native pastures, Paspalum notatum Flugge stands out for having excellent forage value and for being present in all natural pastures of the state (Nabinger and Dall’Agnol 2008). The breeding of this species is an alternative to the use of old and/or exotic varieties, with the search of selected materials; they are eligible for registration at the Ministry of Agriculture, Livestock and Supply (MAPA) and subsequent seed commercialization. The possibility of artificial chromosome duplication of sexual diploid plants from natural populations of variety Pensacola of P. notatum and their use in intraspecific crosses schemes in breeding programs (Burton and Forbes 1961) makes it possible to generate superior genotypes of apomictic

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