Identification of a maize linkage group to apomixis in Brachiaria

A bulked segregant analysis using RFLPs and RAPDs was carried out to identify molecular markers co-segregating with apomixis in a Brachiaria F1 population. The test population used was a cross between sexual B. ruziziensis R44 and the aposporous apomictic Bracharia brizantha cv Marandu. The Brachiar...

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Bibliographic Details
Published in:Theoretical and applied genetics 1997, Vol.94 (3/4), p.439-444
Main Authors: Pessino, S.C, Ortiz, J.P.A, Leblanc, O, Valle, C.B. do, Evans, C, Hayward, M.D
Format: Article
Language:English
Subjects:
apomixis
chromosome mapping
genetic markers
linkage groups
loci
random amplified polymorphic DNA technique
restriction fragment length polymorphism
Urochloa brizantha
Urochloa ruziziensis
Zea mays
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Summary:A bulked segregant analysis using RFLPs and RAPDs was carried out to identify molecular markers co-segregating with apomixis in a Brachiaria F1 population. The test population used was a cross between sexual B. ruziziensis R44 and the aposporous apomictic Bracharia brizantha cv Marandu. The Brachiaria genome was systematically scanned using 61 cDNA and genomic maize clones detecting 65 loci located at 40 cM, on average, one from each other in the maize genome. The finding of a clone that presented a polymorphic band co-segregating with apomixis (umc147) led to the identification of another marker within the same area (umc72). The clones belong to a duplicated linkage group that maps to the distal part of maize chromosome-1 long arm and chromosome-5 short arm. RAPD analysis using 184 primers from Operon sets yielded one more marker (OPC4) significantly linked to the trait mapping the same locus. OPC4 had been previously reported as a potential marker for apospory in Pennisetum. A map of the region was constructed using additional clones that belong to the same maize linkage group. Since that was the only genomic region that presented an apomixis-linked polymorphism our observations support the existence of a single locus directing apospory in Brachiaria.
ISSN:0040-5752
1432-2242