Ploidy levels affect phenotype and cytogenetic traits in Zea mays ssp. mays (2n=20 or 40) and Zea mays ssp. parviglumis hybrids

The aim of this study was to analyse phenotype and cytogenetic behaviour of <i>Zea mays</i> ssp. <i>mays</i> and <i>Zea mays</i> ssp. <i>parviglumis</i> (Zpa) hybrids with different ploidy levels. Maize 2n=20 (Zm20) and Zpa hybrid plants (MPa20) were o...

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Detalles Bibliográficos
Autores principales:	Molina, María del Carmen, García, María Dina
Formato:	Articulo
Lenguaje:	Inglés
Publicado:	2001
Materias:	Ciencias Agrarias Colchicine Embryo rescue Genomic formulae Incompatible crosses Maize hybrids Ploidy level Somatic embryogenesis Zea
Acceso en línea:	http://sedici.unlp.edu.ar/handle/10915/84380
Aporte de:	SEDICI (UNLP) de Universidad Nacional de La Plata

Descripción
Sumario:	The aim of this study was to analyse phenotype and cytogenetic behaviour of <i>Zea mays</i> ssp. <i>mays</i> and <i>Zea mays</i> ssp. <i>parviglumis</i> (Zpa) hybrids with different ploidy levels. Maize 2n=20 (Zm20) and Zpa hybrid plants (MPa20) were obtained naturally, they showed regular meiosis and fertile progeny (+80%). Otherwise, maize 2n=40 (Zm40) and Zpa hybrids (MPa30) were obtained by embryo rescue, they showed irregular meiosis and sterile progeny (0-8%). Meiotic configurations more frequently observed in the species and the hybrids were: Zm20 (10II); Zm40 (3.24II+8.34IV); Zpa (0.46I+9.76II); MPa20 (0.40I+9.54II+0.05III+0.65IV); MPa30 (5.97I+5.93II+4.05III). After colchicine treatment the number of IV increased in Zm20, Zpa and MPa20 and 10III were observed MPa30, because of homoeologous chromosomes pairing. In conclusion, Zm20 (AmAm BmBm) and Zpa (ApaApa BpaBpa) are allotetraploids with 2 homoeologous genomes. Whilst in the hybrids, the homoeologous genomes A pair in all cases, genomes B only do if their homologous competing during pairing, does not exist except in colchicine-treated plants which also show homoeologous genomes B pairing.