L.S.A. Gonçalves, R. Rodrigues, A.T. do Amaral Júnior, M. Karasawa, C.P. Sudré
Published: March 31, 2009
Genet. Mol. Res. 8 (1) : 364-374
DOI: https://doi.org/10.4238/vol8-1gmr549
Cite this Article:
L.S.A. Gonçalves, R. Rodrigues, A.Tdo Amaral Júnior, M. Karasawa, C.P. Sudré (2009). Heirloom tomato gene bank: assessing genetic divergence based on morphological, agronomic and molecular data using a Ward-modified location model. Genet. Mol. Res. 8(1): 364-374. https://doi.org/10.4238/vol8-1gmr549
About the Authors
L.S.A. Gonçalves, R. Rodrigues, A.T. do Amaral Júnior, M. Karasawa, C.P. Sudré
Corresponding author
L.S.A. Gonçalves
E-mail: lsagrural@yahoo.com.br
ABSTRACT
Accessions in gene banks need to be characterized and evaluated to determine their genetic diversity. We made a joint diversity analysis of the tomato gene bank of the Universidade Estadual do Norte Fluminense Darcy Ribeiro in Rio de Janeiro state, using the Ward-modified location model. Forty Solanum lycopersicum accessions were characterized and evaluated for 22 morphoagronomic descriptors and 131 random amplified polymorphic DNA markers. Based on the pseudo-F and pseudo-t2 criteria, the optimal number of groups was established as five. Variability within groups was high for both continuous and discrete nominal data. The first two canonical variables explained about 90% of the inter-group variability. Care should be taken in using the Ward-modified location model technique to avoid incorporating excessive and unnecessary markers, which could favor molecular markers when compared with morphoagronomic variables. However, the minimum number of markers is germplasm- dependent and must be recalculated for each new divergence analysis.
Accessions in gene banks need to be characterized and evaluated to determine their genetic diversity. We made a joint diversity analysis of the tomato gene bank of the Universidade Estadual do Norte Fluminense Darcy Ribeiro in Rio de Janeiro state, using the Ward-modified location model. Forty Solanum lycopersicum accessions were characterized and evaluated for 22 morphoagronomic descriptors and 131 random amplified polymorphic DNA markers. Based on the pseudo-F and pseudo-t2 criteria, the optimal number of groups was established as five. Variability within groups was high for both continuous and discrete nominal data. The first two canonical variables explained about 90% of the inter-group variability. Care should be taken in using the Ward-modified location model technique to avoid incorporating excessive and unnecessary markers, which could favor molecular markers when compared with morphoagronomic variables. However, the minimum number of markers is germplasm- dependent and must be recalculated for each new divergence analysis.
Key words: Solanum lycopersicum, Random amplified polymorphic DNA markers, Joint analysis, Ward-MLM.