Heirloom tomato gene bank: assessing genetic divergence based on morphological, agronomic and molecular data using a Ward-modified location model.
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-t(2) 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.
Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, Brazil. lsagrural@yahoo.com.br
L S A
LS
Gonçalves
R
R
Rodrigues
A T
AT
do Amaral Júnior
M
M
Karasawa
C P
CP
Sudré
D016000:Cluster Analysis; D018744:DNA, Plant / Q000378:metabolism; D030541:Databases, Genetic; D017343:Genes, Plant; D005819:Genetic Markers; D014644:Genetic Variation; D018551:Solanum lycopersicum / Q000145:classification* / Q000235:genetics*
D018744:DNA, Plant; D005819:Genetic Markers