Herança da resistência do acesso de melancia PI 595201 a isolado de PRSV-W do Estado do Tocantins

Abstract

ResumoCom o objetivo de identificar o tipo de herança, o número de genes e os parâmetros genéticos e fenotípicos da resistência do acesso PI 595201 a um isolado de PRSV-W da região Norte do Brasil foi conduzido um experimento na área experimental do Departamento de Produção Vegetal da Universidade Federal do Tocantins, em condições de casa de vegetação. A partir do cruzamento entre a cultivar suscetível Crimson Sweet (P 1 ) e o acesso resistente PI 595201 (P 2 ) foi obtida a geração F 1 e as gerações segregantes, cujas plantas foram inoculadas e avaliadas quanto à resistência com base nos sintomas nas folhas. Foram avaliadas 48, 48, 80, 200, 100 e 100 plantas das gerações P 1 , P 2 , F 1 , F 2 , RC 11 e RC 12 , respectivamente, em delineamento inteiramente casualizado com quatro repetições. A partir da análise de componentes de médias no controle da resistência determinaram-se dois genes, predominando os efeitos gênicos aditivos, seguido de efeitos de dominância incompleta no sentido de aumentar a resistência. As herdabilidades para a resistência, no sentido amplo e restrito, foram de 0,48 e 0,38, respectivamente.Palavras-chave: Citrulus lanatus var. lanatus, Potyvirus, resistência genética, componentes principais. Inheritance of the resistance of the watermelon accession PI 595201 to a PRSV-W isolate from the State of Tocantins AbstractAiming to identify the type of inheritance, the number of genes and genetic and phenotypic parameters of PI 595201 access resistance to an isolate of PRSV-W in the North of Brazil, was conducted an experiment in the experimental area of the Department of Plant Production of the Universidade Federal do Tocantins, in a greenhouse. From the cross between the susceptible cultivar 'Crimson Sweet' (P 1 ) and resistant access 'PI 595201' (P 2 ) was obtained F 1 and segregating generations, whose plants were inoculated and evaluated for resistance based on leaf symptoms. Was evaluated 48, 48, 80, 200, 100 and 100 plants of P 1 , P 2 , F 1 , F 2 , RC 11 and RC 12 generations, respectively, in a completely randomized design with four replications. From the analysis of medium components in the control of resistance were determined two genes, predominantly additive gene effects, followed by effects of incomplete dominance to increase the resistance. The heritability for resistance in broad and narrow sense were 0.48 and 0.38, respectively.

Susceptibility assessment of watermelon and pumpkin cultivars to potyvirus in Tocantins

“…The occurrence prevalence of single and mixed infections of potyvirus PRSV-W, ZYMV and WMV in the State of Tocantins, differed between regions (ALVES et al, 2014). Several studies have shown that PRSV-W has a high incidence in cucurbit crops in the Northeast of Brazil (DO NASCIMENTO et al, 2012.).…”

Inheritance of resistance to damping-off (Rhizoctonia solani) in watermelon

“…Variance components Heritabilities (%) It is fundamental to perform the evaluation of the accession reaction with an aggressive and efficient isolate to avoid escape. As well as the parents who will originate the segregating population should be as homogeneous and contrasting as possible (Alves et al 2014). Thus, the results of experiment II proved to be efficient in having homogenous and contrasting parents, which allowed determining that the inheritance is polygenic and controlled by at least nine genes with additive effect and low heritability.…”

“…Narrow-sense heritability considers only the additive genetic variance, which is the one that is fixed by selection, which is the most important for the breeder (Ramalho et al 2012). Thus, the magnitude of heritability was low, as seen by Alves et al (2014) working with genetic inheritance to the PRSV virus reaction in watermelon. Thus, breeders should seek recurrent selection as a method to gradually increase the frequency of desirable alleles for the quantitative characteristic, through repeated selection cycles, which favors the increase of narrow-sense heritability (Borém and Miranda 2009).…”

Inheritance of resistance to papaya ringspot virus-watermelon strain (PRSV-W) in 'Whitaker' summer squash line

“…Inheritance of PRSV-W resistance has been elucidated in other cucurbit crops, such as muskmelons (Pitrat and Lecoq 1983) and watermelons (Azevedo et al 2012, Alves et al 2014. Resistance in C. maxima and C. moschata is controlled by more than one gene.…”