Base genética da resistência de um acesso de tomate silvestre ao mosaico-amarelo do pimentão

Abstract

Resumo -O objetivo deste trabalho foi avaliar a base genética da resistência de Lycopersicon hirsutum ao potyvírus Pepper yellow mosaic virus (PepYMV). Foram avaliadas 540 plantas, inclusive os parentais 'Santa Clara' (suscetível) e 'BGH 6902' (resistente), e as gerações F 1 , F 2 , RC 1:1 e RC 1:2 , derivadas do cruzamento desses parentais. As plantas receberam inoculações mecanicamente, e a concentração viral de PepYMV em cada planta foi determinada por ELISA indireto. Foram realizadas as análises quantitativa e qualitativa. A primeira, baseada na concentração viral de cada planta, indicou herança oligogênica com herdabilidade de 99%. Os mesmos dados, quando analisados de forma qualitativa, indicaram herança governada por dois genes, com interação epistática dominante e recessiva. Entretanto, quando foi analisada a geração F 2:3 , oriunda da autofecundação de plantas F 2 resistentes, a hipótese de dois genes foi descartada e a de um gene, com dominância completa entre os alelos, foi a que melhor se ajustou aos dados. A análise qualitativa, pela sintomatologia observada, demonstrou que a herança da resistência ao PepYMV é determinada por um gene recessivo, com ausência de dominância entre os seus alelos.Termos para indexação: Lycopersicon hirsutum, Pepper yellow mosaic virus, herança da resistência, resistência recessiva. Resistance genetic basis of a wild tomato access to pepper yellow mosaic virusAbstract -The aim of this work was to evaluate the genetic basis of resistance of Lycopersicon hirsutum to the potyvirus Pepper yellow mosaic virus (PepYMV). Five hundred and forty plants, including the parentals 'Santa Clara' (susceptible) and 'BGH 6902' (resistant) were evaluated, as well as the generations F 1 , F 2 , RC 1:1 and RC 1:2 , from the crossing of the above parentals. PepYMV was mechanically inoculated, and the virus concentration in each plant was determined by indirect ELISA. The quantitative and qualitative analyses were carried out. The first one, based on the virus concentration of each plant, suggest oligogenic inheritance with heritability of 99%. The same data, when analyzed under the qualitative form, indicated an inheritance governed by two genes, with dominant and recessive epistatic interaction. However, when F 2:3 generation, arising from self-fertilization of resistant F 2 plants, was analyzed, the hypothesis of two genes was rejected, while the best fitted to data was that of one gene with complete dominance among the alleles. The qualitative analysis, considering sintomatology observed, showed that the inheritance of resistance to PepYMV is determined by a recessive gene, with the absence of dominance among their alleles.

Inheritance of resistance to Pepper yellow mosaic virus in Capsicum baccatum var. pendulum

“…Heritability values related to diseases have been quite variable, as observed in some studies, such as those also on solanaceous plants carried out by Riva et al (2004) and Juhász et al (2008). Broad-sense heritability for resistance to bacterial spot in C. annuum L. was estimated at 82.50 and 85.58%, respectively, when two resistance components (number of pustules on leaves and rating scale) were tested.…”

“…Thus, the search for new sources of resistance to PepYMV and subsequent determination of genetic control are essential for breeding programs aimed at releasing sweet and chili pepper cultivars (Juhász et al, 2008).…”

The inheritance of late blight resistance derived from Solanum habrochaites

“…The characterization of over than 350 tomato accessions of the BGH (http://www. bgh.ufv.br) resulted in define many resistance sources as well as to Tuta absoluta (Moreira et al 2005, Oliveira et al 2009), potyvirus (Zucchini yellow mosaic virus, ZYMV and Pepper yellow mosaic virus, PepYMV) (Moura et al 2005, Juhász et al 2008, whitefly (Bemisia tabaci biotype B) (Fernandes et al 2009), Phytophthora infestans (Abreu et al 2008) and geminivirus (Tomato yellow spot virus, ToYSV) (Aguilera et al 2008). …”

Variabilidade genética em tomate (Solanum lycopersicon Mill.) por marcadores ISSR

“…The agronomic characterization of over than 350 tomato accessions of the BGH (http://www.bgh.ufv.br) has been accomplished together with the characterization of different resistance to Tuta absoluta (Oliveira et al, 2009;Moreira et al, 2005), potyvirus (Zucchini yellow mosaic virus, ZYMV and Pepper yellow mosaic virus, PepYMV) (Moura et al, 2005;Juhász et al, 2008), whitefly (Bemisia tabaci biotype B) (Fernandes et al, 2009), Phytophthora infestans (Abreu et al, 2008) and geminivirus (Tomato yellow spot virus, ToYSV) (Aguilera et al, 2008). The agronomic characterization and molecular information could provide a great support for breeding programs by including all these data in a joint analysis that takes in account all the variables that enhance the selection process of parents with high divergence.…”