Transformação de dados nas estimativas de parâmetros genéticos da resistência dos cultivares de soja Uberaba e Bossier à Cercospora sojina Hara

Abstract

Foram estudados os efeitos da transforma0o de dados sobre a significancia de parâmetros genéticos da heranga da resistência da soja Cercospora sojina Hara. As médias e variancias das geraOes P1, P2, Fl, F2, RCS e RCR de urn cruzamento envolvendo o cultivar resistente Uberaba e o suscetivel Bossier foram avaliadas utilizando cinco caracterfsticas associadas corn a doenga: gran de infecçäo avaliado visualmente (GI); numero de lesOes por folfolo (NLF); diâmetro médio da Iesäo (DML); porcentagem de area foliar lesionada (PAFL); e indice de doenga (ID). As transforma0es estudadas foram: raiz quadrada de (x), (x+1), (x+O5) e (x+3/8) e logaritmo de (x+1). Os resultados evidenciaram que: a) as transfonna0es de dados nao alteraram as significancias das estimativas dos parametros genéticos (m, a, d) de todos os caracteres estudados, exceto do carter PAFL transformado em raiz quadrada de (xi-1); b) a transformagao logaritmo de (x+1) alterou a significancia da interaçAo aditivo-dominante (ad) nos caracteres GI, NLF e ID e da interaçAo aditivo-aditivo (aa) no caster PAFL; c) a transforma0o raiz quadrada de (x+1) alterou a significancia da interação ad no carter GI e da interaçAo aa no carter PAFL; e d) Os efeitos genéticos aditivos foram Os mais importantes na determinaçao dos caracteres relacionados corn a resistência da soja cercosporiose, tanto corn os dados transformados como corn os nao-transformados.

A The effect of data transformation on the estimates of genetic parameters of soybean resistance to Cercospora Sajina Hara-inheritance was studied. The means and variances of P,, P2,F,, FZ, backcross to the susceptible parent - RCS and backcross to the resistant parent - RCR populations of. a cross involving the resistant (Uberaba - P,) and the susceptible (Bossier - Pg) 'cultivars were evaluated for five characteristics associated with the disease: visually evaluated infection degree (Gl), number of lesions per foliole (NLF), lesion mean diameter(DML), percentage of lesioned leaf area (PAFL) and disease index (ID). The studied transformations were: square root of (x), (x+1), (x+0.5) and (x+3/8) and logarithm of (x+l). The results evidenced that: a) the transformations did not alter the significance of _theestirmted genetic parameters (m, ,a, (1) for all evaluated characters, except for square root of (x+l) of PAFL; b)lthe11ogarithm of (x+l) transformation altered the significance of the additive-dominant interaction (ad) on GI, NLF and ID characters and the additive-additive interaction (aa) on PAFL , character; c)” the square root of (x+l) transformation altered the significance of the ad interaction on GI, character and of a interaction on _PAFL; and d) theadditive genetic effects were the most important in the detennination of all characters related with the resistance of soybean to frogeye leaf spot, both for the transformed and non-transformeddata.