Data/hora: 18/06/2024 12:45:58

Biblioteca(s): 	Embrapa Soja.	
Data corrente: 	06/04/2004	
Data da última atualização: 	27/07/2007	
Autoria: 	BIONE, N. C. P.; PAGLIARINI, M. S.; ALMEIDA, L. A. de.	
Título: 	Meiotic mutations causing male sterility in soybean [Glycine max (L.) Merrill].	
Ano de publicação: 	2004	
Fonte/Imprenta: 	In: WORLD SOYBEAN RESEARCH CONFERENCE, 7.; INTERNATIONAL SOYBEAN PROCESSING AND UTILIZATION CONFERENCE, 4.; CONGRESSO BRASILEIRO DE SOJA, 3., 2004, Foz do Iguassu. Abstracts of contributed papers and posters. Londrina: Embrapa Soybean, 2004.	
Páginas: 	p. 240-241.	
Série: 	(Embrapa Soja. Documentos, 228). 
	
Idioma: 	Inglês	
Notas: 	Editado por Flávio Moscardi, Clara Beatriz Hoffmann-Campo, Odilon Ferreira Saraiva, Paulo Roberto Galerani, Francisco Carlos Krzyzanowski, Mercedes Concordia Carrão-Panizzi.	
Conteúdo: 	Meiosis, a universal process in the life history of sexual organisms, provides opportunities for genetic re-assortment. Molecular data suggest that this process possesses a very conservative set of genes controlling each divisional step. Mutations that selectively eliminate male reproductive function and leave female function unimpaired have potential application in hybrid seed production. Mutations affecting microsporogenesis and causing complete male sterility has been detected in some lines from Embrapa Soybean breeding program. In the line BR97-13777H, many univalents and few bivalents were found in diakinesis. The main and distinctive characteristic of this mutant was the complete inability of univalents to congregate in the metaphase plate. Scattered in the cytoplasm, univalents underwent premature sister chromatid separation, so that 80 chromatids could be easily counted. Telophases II with a varied number of different-sized nuclei were observed. The inability of univalents to congregate at the equator made us classify it as asynaptic mutant. A desynaptic mutation has been detected in BR97-12986H. The meiotic behavior was similar to that described for the st series of synaptic mutants previously reported in soybean. Distinctly different in their behavior from st series soybean mutants, telophase I micronuclei of different sizes organized their own spindle in the second division. This behavior contributed towards an increase in genome fractionation. Several microspores and microcytes of different sizes were recorded at the end of meiosis. A mutation affecting microspore development was detected in the line BR97-13509H. The main cause of male sterility was the absence of cytokinesis after telophase II. Instead of the typical tetrads of microspores four nucleate coenocytic microspores were formed. In the line BR97-17971, analyses of microsporogenesis revealed a differential meiotic behaviour in relation to ms2. Sterile plants have different levels of meiotic abnormalities related to chromosome segregation. The main meiotic cause of pollen sterility was the absent or the defective cytokinesis following telophase II. After telophase II, 1 to 4 nucleate microspores underwent degeneration. Cross-sections of sterile plants showed that at telophase II the tapetal cells with large vacuoles entered degeneration. Despite callose deposition around meiocytes, sterile plants did not form tetrads. They degenerated and collapsed after callose dissolution, forming an amorphous mass. Anthers from male-sterile plants were shrivelled. Up to date, several male-sterile, female fertile soybean mutants have been reported. It is very intriguing why most of them share the same cytological characteristics although they are non-allelic. Studies of genome organisation and linkage could help us to understand better why sterile mutations of independent loci shared the same cytological expressions.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Soja (CNPSO)	
Exemplares: 	CNPSO - (23750-1) - UMT - PL - -- - RF 633.34072 - W927a -  - DIS