Abstract

FLORES-MAYA, Saúl; OLIVARES-CARRILLO, José Luis; FLORES-CRESPO, Lucina Irene  and  RIVERA-AGUILAR, Víctor. ESTUDIO CITOGENÉTICO DEL MAÍZ HÍBRIDO SIMPLE H-311 (ZEA MAYSSSP. MAYS), TEOCINTLE CHALQUEÑO (ZEA MAYS SSP. MEXICANA) Y SU HÍBRIDO F1 (ZEA MAYS SSP. MAYS X ZEA MAYS SSP. MEXICANA). Polibotánica [online]. 2005, n.20, pp.47-72. ISSN 1405-2768.

Meiotic prophase and metaphase I chiasma frequency was analyzed in cells of maize hybrid simple H-311 (Zea mays ssp. mays), teosintle chalqueño (Zea mays ssp. mexicana) and their resulting hybrid F1(Zeamays ssp. mays X Zea mays ssp. mexicana). Chiasma frequencywas smaller in F1 than in its progenitors. Mean total chiasms per cell was 21.88 in maize hybrid simple H-311, 21.31 in teosintle chalqueño and 16.63 in the F1. In the hybrids, the crossing between homologous chromosomes was irregular, presenting univalents, trivalents, tetravalents, pentavalents and hexavalents.All three plant types presented a diploid chromosome number of 2n = 20. Themean total length per genomewas 33.51 μmin maize hybridsimple H-311, 33.18 μm in teosintle chalqueño and 33.33 μm in the F1. The total length of the chromosomesof all threegenomeswas similar, with a length between 2 and 5 μm. The three karyotypes constituted of metacentric and submetacentric chromosomes. Maize hybrid simple H-311 and teosintle chalqueño presented a close phylogenetic relationship, as they had the same chromosome number and similar relationships and lengthsbetween chromosome arms.Moreover, the hybrid F1 genome presents chromosome pairing and genetic exchange between chromosomes of both plants.

Keywords : chiasma; Bchromosome; karyotype; Zeamays ssp. mays; Zeamays ssp.mexicana.