Meiotic studies of spontaneous hybrids of Amaranthus: genome analysis |
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Authors: | E. J. Greizerstein L. Poggio |
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Affiliation: | Institute Fitotécnico de Sta. Catalina (FCAF, UNLP)-Centro de Investigaciones Géneticas (UNLP-CONICET-CIC), C.C. 4, 1836 Llavallol, Buenos Aires, Argentina;Departamento de Ciencias Biologicas (FCEN, UBA), Buenos Aires, Argentina |
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Abstract: | The meiotic behaviour of 13 spontaneous interspecific F1 hybrids of Amaranthus was studied. The hybrids between species with n= 16 chromosomes had 16 bivalents but varied considerably in pollen stainability (0–55%). These results suggest the existence of cryptic structural hybridity. The hybrids involving A. cruentus (n = 17) and species with n = 16 (A. caudatus and A. quitensis) always formed 15II+1 III with very low pollen stainability (5–7%). Further observations indicated that Amaranthus species are allotetraploids with basic numbers of x= 8 and x= 9 but exhibit x= 16 and x= 17 as secondary basic numbers, as demonstrated by (a) the frequent presence of 811 + 171 in the meiosis of the hybrid A. spinosus (n = 17) × A. hybridus (n= 16); and the occurrence of secondary associations between bivalents in MI. Genomic formulae are proposed for each species, on the basis of the meiotic behaviour of the hybrids studied. |
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Keywords: | Amaranthus basic chromosome number genome analysis homeology hybrids meiotic behaviour polyploidy pseudocereal |
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