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Genetic variability in salt tolerance during germination of Stylosanthes humilis H.B.K. and association between salt tolerance and isozymes
Maria Bernadete LovatoI; Paulo Sodero MartinsII†
IDepartamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Caixa Postal 486, 31270-010 Belo Horizonte, MG, Brasil. Send correspondence to M.B.L.
II†Departamento de Genética, Escola Superior de Agricultura "Luiz de Queiroz", Caixa Postal 83 , 13418-900 Piracicaba, SP, Brasil.
ABSTRACT
Variation in salt tolerance of six natural populations of Stylosanthes humilis from three ecogeographic regions, Mata (wet tropical climate), Agreste and Sertão (semi-arid tropical climate) of Pernambuco State, Northeast Brazil, was evaluated on germination in 201 mM NaCl. There were significant differences among families of all populations for germination percentage and of five populations (except Tamandaré, from Mata) for germination rate. Populations from semi-arid regions presented high coefficients of genetic variation, those from Agreste being higher than those from Sertão. Populations from Mata showed low coefficients of genetic variation. The coefficients of genotypic determination were high for five population, except Tamandaré, both for germination percentage (≥ 0.89) and for germination rate (≥ 0.79), indicating the possibility of selection for salt tolerance in these populations. An electrophoretic analysis of esterase and peroxidase isozymes was also performed in the six populations, and correlations were estimated between salt tolerance and allelic frequencies. The analysis of salt tolerant and salt sensitive families of populations from Agreste suggested an association of alleles of a peroxidase locus with salt tolerance during germination in the Caruaru population.
Keywords: Genetic variability; salt tolerance; Stylosanthes humilis.
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