Data/hora: 21/06/2024 05:53:13

Biblioteca(s): 	Embrapa Soja.	
Data corrente: 	12/04/2000	
Data da última atualização: 	15/10/2004	
Autoria: 	SOUZA, P. I. M.; SPEHAR, C. R.; FARIAS NETO, A. L.; MOREIRA, C. T.	
Título: 	Soybean crop in the brazilian savannah: breeding and evolution.	
Ano de publicação: 	1999	
Fonte/Imprenta: 	In: WORLD SOYBEAN RESEARCH CONFERENCE, 6., 1999, Chicago. Proceedings: invited and contributed papers and posters. Chicago: University of Illinois / Soybean Research & Development Council, 1999.	
Páginas: 	p.498.	
Idioma: 	Inglês	
Conteúdo: 	Soybean cultivation was first introduced in Southern Brazil, as a temperate zone crop, originated from high latitude. It is not surprising that first adapted varieties were of North American origin, such as, Bragg, Davis, Hardee, Lee and Hood. The area for soybean production in this part of the country was soon occupied and the only possible increase in cultivated land had to be in the tropics, especially in the savannah which were virtually waste land until the early 1970's. The main constraints for prompt expansion in grain crops were lack of adapted varieties to low latitudes, reduced soil fertility and insufficient infrastructure in the region. The Savannah is characterised by two seasons: rainy and dry; without extremes of temperature to soybeans and the amount of rain is adequate, despite of irregular distribution (dry spells). By the end of 1970's, new varieties started to be released to farmers in the region and in the late 1990's it became a major producer, responding for about 50% of national production. In the long run, when soil problems are overcome, the average yields are, in general, higher than in the traditional zone of the south. The presently cultivated area with annual crops is of 10 million hectares, 65% of wich covered by soybeans. This is only a small part of total savannah area (204 million ha). It is estimated that about 80 million ha are still waiting to be occupied for grain production. The key factor to turn this regions into a major soybean producer has been the acquisition of genotypes with long juvenile phase. Initially late types from the South were introduced in the savannah where they were reduced in yield and plant height. The first crosses were made in the Agronomic Research Institute of Campinas (IAC), using late flowering introductions like 'PI 240664', from Philippines, 'PI 159925', Santa Maria, From Peru. New mutants for lateness like 'PR 77-10011'from Bragg and 'Paranagoiana', from cultivar Parana, were recovered and included to increase the gene pool of crosses. The almost linear expansion of soybean cultivation in the savannah has been closely linked to acquisition of improved cultivars that respond for higher yields than pioneer varieties. 'BR/Emgopa-313', 'BR-9 Savanna', 'BRS-60 Celeste',  'BRS-55' Uirapuru', 'MG/BR 45 Conquista', 'FT Cristalina'and 'Vitoria'are among the outstanding performers. To consolidate the soybean expansion, on a sustainable basis in the savannah, new hurdles must be overcome, such as resistance to late diseases like the one caused by Colletrotrichum, and pests of recent outbreaks like cyst nematode and insects the new cultivars should also belong to different maturity groups. These favourable characteristics shall help to overcome the natural limitations of the region and allow diversification of grain production systems.	
Palavras-Chave: 	Brasil; Soybean.	
Thesagro: 	Cerrado; Melhoramento; Soja.	
Thesaurus Nal: 	Brazil; breeding; savannas.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Soja (CNPSO)	
Exemplares: 	CNPSO - (17411-1) - ADD - PL - -- - 633.34072 - W927p -  - DIS