Data/hora: 22/09/2024 12:15:26

Biblioteca(s): 	Embrapa Soja; Embrapa Trigo.	
Data corrente: 	18/12/1995	
Data da última atualização: 	18/12/1995	
Autoria: 	DALL'AGNOL, A.	
Título: 	Flowering and fruiting patterns of five determinate soybean cultivars.	
Ano de publicação: 	1980	
Fonte/Imprenta: 	[S.l.]: University of Florida, 1980.	
Páginas: 	89 p.	
Idioma: 	Inglês	
Notas: 	Dissertação PhD.	
Conteúdo: 	Soybean (Glycine max L. Merrill) cultivars are unable to maintain photosynthetic rates sufficient to supply carbon and support nitrogen assimilation necessary to sustain both seed fill and photosynthesis. However, a high rate of flower shedding before seed development starts is common in soybeans. The purpose os this study was to determine the origin and location of floral buds; number, location, and fate of flowers produced; and to relate abscission of flowers and pods to stage of development of soybean cultivars - Davis, Braxton, F67-3673, F73-7909, and Cobb-planted at Gainesville, Florida. Flower counts were taken from samples of eight (Experiment 1) and four (Experiment 2) random plants per cultivar cut at 2-day intervals throughout the flowering period. Cultivars planted 9 June (Experiment 1) averaged 340 flowers per plant and 16% pod set sucess with a range of 10 to 20% among cultivars. Main stems, primary branches, and higher order branches produced 27, 40, and 33% of the total flowers and 22, 31, and 47% of total pods, respectively. Later formed flowers on secondary and tertiary branches had 22% pod set sucess, almost twice the 12% for earlier formed flowers on main stem and primary branches. Plant seeded 19 July (Experiment 2) averaged 87 flowers each with 32% pod-set sucess. Main stems, primary branches, and secondary branches, produced 35, 50 and 15% of the total flowers, 33, 61, and 6% of the total pods, giving a pod-set sucess of 30, 39, and 13%, respectively. Delaying planting 40 days shifted the highest percentage pod-set sucess from secondary and tertiary branches to main stems and primary branches. One top, one bottom, and one branch node were selected for intensive study to describe flower and pod development on upper and lower sections of the main stem and on primary branches. In Experiment 2 we studied a total of 1,613 floral buds from the three selected nodes on 40 plants. Twenty percent of the floral buds produced mature pod. Pod set success for primary, secondary, tertiary, and quartic floral buds was 8, 27, 27, and 21%, respectively. Main stems and branches produced 39 and 61% of all floral buds and had pod-set success of 13 and 24% respectively. In Experiment 2, we obtained 22% pod-set success from 334 floral buds on 20 plants. Nearly all flowers were from primary and secondary buds. Pod-set sucess was 37 and 10%, respectively. These results have practical implications, particularly in breeding programs. They indicate that crossing sucess per hand pollinated flower is greatest when female flowers are on primary branches of late plated parents. When early planted adapted parents are used as females, delaying crossing until flowers on secondary branches are opening will increase the probability for obtaining hybrid seed.	
Palavras-Chave: 	Soybean.	
Thesagro: 	Fisiologia; Floração; Genética; Melhoramento; Soja.	
Thesaurus Nal: 	flowering; genetics; physiology; plant breeding.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Trigo (CNPT)	
Exemplares: 	CNPSO - (1019-1) - UPC - TS - -- - 19/80 -  - 19/80 - DIS
CNPT - (30019-1) - ADD - TS - -- - TS-0439 -  - 0439 - DIS