Crescimento e nutrição de mudas de abacaxizeiro ‘Imperial’ associadas com o fungo Piriformospora indica e aplicação de herbicidas

Abstract

A baixa oferta de mudas sadias e com qualidade tem sido um obstáculo para o crescimento da abacaxicultura no Brasil. A pesquisa foi realizada com o objetivo de avaliar a associação micorrízica, o crescimento e absorção de nutrientes em mudas micropropagadas de abacaxizeiro 'Imperial' inoculadas com o fungo Piriformospora indica em cultivo com a aplicação de herbicidas. Foi utilizado o esquema fatorial 2 x 4, sendo os fatores duas inoculações: mudas inoculadas com o fungo P. indica e sem inoculação e quatro doses de herbicidas: 0; 1,5; 3,0 e 6,0 L ha -1 para o ametryn, 0; 1,6; 3,2; 6,4 L ha -1 para o diuron e 0; 0,4; 0,8 e 1,6 L ha -1 para o sulfametrazone, distribuídos no delineamento inteiramente casualizado, com três repetições. As doses dos herbicidas foram aplicadas ao substrato antes do plantio das mudas. A inoculação com o fungo P. indica foi feita no momento do plantio, colocando-se no substrato discos de micélio de 5 mm, contendo estruturas fúngicas. Aos 150 dias após a inoculação foi feita a análise da colonização micorrízica, dos teores de N, P e K e do crescimento das mudas. Os dados foram submetidos à análise de variância, regressão polinomial e comparação de médias, a 5% de probabilidade. Foi observada a associação do fungo P. indica com as mudas de abacaxizeiro 'Imperial' com a aplicação de todos os herbicidas. As mudas associadas com o fungo apresentaram maiores teores de nutrientes e crescimento. A aplicação dos herbicidas em doses elevadas interferiu no crescimento e na absorção de nutrientes pelas mudas de abacaxizeiro micorrizadas. Palavras-chave: Ananas comosus, associação micorrízica, estado nutricional AbstractThe low supply of healthy and quality nursery plants has been an obstacle to the growth of pineapple crop in Brazil. The research was carried out with the aim of evaluating mycorrhizal association, growth and nutrient uptake of 'Imperial' micropropagated pineapple plants inoculated with the fungus Piriformospora indica in cultivation with herbicide application. The 2 x 4 factorial scheme was used, being the factors the two inoculations: inoculated nursery plants with the fungus P. indica and without

The growth and nutrition of pineapple (Ananas comosus L.) plantlets under different water retention regimes and manure

“…For magnesium, there were no statistical differences regarding organic sources and use of the hydrogel for the two cultivars. In addition, the average values presented in this work for leaf calcium and magnesium contents were lower than those considered suitable by nutritional studies with pineapple seedlings during the acclimatization stage (Teixeira et al, 2009;Baldotto et al, 2009;Leonardo et al, 2013;Ramos et al, 2011;Cruz et al, 2015).…”

“…Fagundes et al (2015), studying a water absorbing polymer for the reduction of nutrients leached during the production seedlings of yellow passion fruits, found that N losses by leaching decreased as the dose of the polymer increased: there was a decrease of 47.8% on the leached material of a Bioplant ® substrate and a decrease of 33.4% on a Provaso ® substrate during the evaluation of nutrients.…”

“…As for the "Imperial", nitrogen was not influenced by organic sources and hydrogel (Table 5). Fagundes et al (2015), studying water absorbing polymers for the reduction of nutrients leached during the seedling production of yellow passion fruits, found that N losses by leaching decreased as the dose of the polymer increased in relation to the leached material without the incorporation of a water absorbing polymer. Furthermore, bovine manure may have influenced the substrate and was structurally reflected in the decrease of the leachate of this nutrient.…”

High phosphorus fertilization reduces mycorrhizal colonization and plant biomass of three cultivars of pineapple

“…Cayenne and Champaka produced similar biomass and MD2 a little less than these two cultivars, which can be explained because Champaka is a pure clone obtained from Cayenne. MD2 is a hybrid obtained from a different phylogenetic group, and its management is highly demanding of nutrients, mainly K, due to its fast growth and is very susceptible to fungal attack (Barreto-Cruz et al, 2015;Valleser, 2019). Excessive fertilizer applications in f ield production and tested in this work under greenhouse conditions proves again that high P quantities reduce AMF development, as reported in previous research (Balzergue et al, 2011), and in these pineapple cultivars may even cause crop growth depressions.…”