Resumo O mamoeiro (Carica papaya L.) é uma fruteira de bastante interesse econômico e alimentar em todo o mundo. Sua propagação pode ocorrer tanto por via sexuada como assexuada. Tradicionalmente é propagado por sementes, entretanto, a propagação vegetativa vem sendo frequentemente utilizada com o uso de técnicas de cultura in vitro e ex vitro. Na propagação vegetativa o método de estaquia tem sido bastante explorado. Pesquisas também tem sido desenvolvidas utilizando-se a enxertia. A cultura do mamoeiro tem se tornado também, nos últimos anos, um modelo para outras fruteiras no que diz respeito ao uso de técnicas biotecnológicas, visando aplicações que vão da conservação de germoplasma a transformação genética de plantas. Desde o início da década de 70, a cultura de tecidos do mamoeiro vem sendo intensamente estudada, permitindo maior controle do desenvolvimento in vitro, especialmente para as técnicas de micropropagação, organogênese e embriogênese somática.

Abstract Papaya (Carica papaya L.) is a fruit tree of great economic and food interest worldwide. Its propagation can occur both sexually and asexually. Traditionally, it is propagated by seeds; however, vegetative propagation has been often used with the use of in vitro and ex vitro culture techniques. In vegetative propagation, the cutting method has been extensively explored. Research has also been developed using grafting. In recent years, papaya cultivation has also become a model for other fruit plants in the use of biotechnological techniques aiming applications ranging from germplasm conservation to genetic transformation of plants. Since the beginning of the 1970s, the culture of papaya tree tissues has been intensely studied, allowing greater control of in vitro development, especially for micropropagation, organogenesis and somatic embryogenesis techniques.

ABSTRACT Despite the widespread distribution of the Cassava common mosaic virus (CsCMV) in Brazil, little is known about the losses it causes in yield. The effect of CsCMV on different varieties was evaluated by reference to several agronomic traits. Four field trials were established in 2012/2013 and 2013/2014 using six varieties of cassava. Following mechanical inoculation with CsCMV, the presence of the virus was confirmed using the ELISA assay. The evaluated traits were plant height (PH), dry matter content (DMC), harvest index (HI), aerial part yield (APY), root yield (RoY), and starch yield (StY) in both inoculated and non-inoculated plants. Overall, the presence of the virus contributed little to the reduction in PH, HI, and DMC across the varieties, with PH being significantly reduced by 9.2 and 7.0 % in the BGM0212 and BRS Kiriris varieties, respectively. In contrast, APY, RoY, and StY were reduced by 30.2, 29.3, and 30.0 %, in the virus-infected plants respectively. While the BRS Kiriris and BRS Jari varieties suffered the highest reductions overall and were considered highly susceptible to CsCMV, none of the traits suffered reductions in the inoculated BRS Formosa plants. Although RoY and StY were reduced in inoculated plants of BRS Tapioqueira, crop yield for this variety was the highest. Thus, BRS Formosa and BRS Tapioqueira exhibited tolerance against CsCMV, which warrants further investigation.

Papaya (Carica papaya) is a fruit crop of great economic and social importance for Brazil and other papaya-producing countries. Brazil is the second largest producer in the world. The papaya sticky disease, caused by Papaya meleira virus (PMeV), has caused great losses in the major Brazilian papaya-producing states. In order to estimate the genetic diversity of PMeV, latex samples were collected from papaya plants in the states of Bahia, Espírito Santo, Pernambuco, Ceará and Rio Grande do Norte, and total RNA was extracted. Specific primer for the replicase region allowed the amplification, by RT-PCR, of a fragment of approximately 560 bp from 31 isolates. The sequence analysis indicated a level of conservation greater than 88% among isolates. Furthermore, comparative analyzes indicated that PMeV has similarity with mycoviruses of the family Totiviridae. This phylogenetic relationship was reinforced by the presence of conserved motifs within in the RdRp regions from mycoviruses.