Data/hora: 21/09/2024 10:18:45

Biblioteca(s): 	Embrapa Soja.	
Data corrente: 	15/10/1992	
Data da última atualização: 	28/10/2004	
Autoria: 	CEDENO, J. R.; McMULLEN, M. S.; MILLER, J. F.	
Título: 	Cytogenetic relationship between Helianthus annuus L. and H. tuberosus L.	
Ano de publicação: 	1985	
Fonte/Imprenta: 	In: CONFERENCIA INTERNACIONAL DE GIRASOL, 11., 1985, Mar del Plata. Actas. Mar del Plata : ASAGIR / ISA, 1985.	
Volume: 	t.2	
Páginas: 	p.541-546.	
Descrição Física: 	i	
Idioma: 	Inglês	
Conteúdo: 	Eleven populations of Helianthus tuberosus L. were used in crosses with the Helianthus annuus L. inbred line HA89 in order to study the cytogenetic relationship of the two species and the fertility of the F1 hybrids and their backcross progeny. Pollen fertility of 180 F1 hybrids and 170 BC1 progeny was studied. Samples of pollen were placed in acetocarmine for three days and only well-colored grains with well stained sperm nuclei were scored as fertile. The mean fertility of the F1 hybrids was 17.2% with a range of 1.2 to 34.2%. The mean fertility of the BC1 progeny was 3.0% with a range of 0.0 to 11.6%. In most hybrids it was not possible to obtain good preparations allowing a clear chromosome analysis and only 27 F1's were analyzed cytologically. The bivalent mean of the F1 was 21.2 per cell with a range of 8 to 34. The pairing configurations were scored at diakinesis and the number of bridges and fragments was recorded at anaphase I and early telophase I. The largest chromosome association was a chain of eight chromosomes and the maximum number of bridges observed was six. According to these results the two species may differ by three reciprocal translocations and by six paracentric inversions, but homeologous pairing is likely to account for much of the multivalent formation because of the amount of pairing observed. The mean of bivalents in the BC1 progeny was 15.19 with a range of 10 to 24. Trivalents averaged 1.57 per cell. In this hexaploid X diploid cross the pairing is very good and suggests ...	
Palavras-Chave: 	Citogenetics; EUA; Sunflower; USA.	
Thesagro: 	Citogenética; Genética; Girassol; Helianthus Annuus; Helianthus Tuberosus.	
Thesaurus Nal: 	genetics.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Soja (CNPSO)