In vitro multiplication of wild Manihot species with different naphthaleneacetic acid and benzylaminopurine concentrations

In vitro multiplication is an important tissue culture technique that is capable of efficiently producing seedlings at any scale. It is a propagation method based on the aseptic culture of small propagules in a suitable culture medium to enable plant regeneration. Multiplication experiments conducted in vitro to set protocols adapted to wild Manihot species have used modified mineral salts and MS vitamins as basic culture medium. Here, 25 treatments based on combinations of the regulators benzylaminopurine (BAP) and naphthaleneacetic acid (NAA) at 0, 0.025, 0.05, 0.075, and 0.1 mg L-1 were used for in vitro multiplication of three genotypes of wild Manihot species (M. violaceae Pohl Müll. Arg., M. pseudoglaziovii Pax & Hoff., and M. flabellifolia Pohl). Plant height and the number of 1 cm minicuttings, number of roots, shoots, green leaves and senescent leaves were recorded 120 days after explant inoculation. M. violaceae Pohl. Müll. Arg. and M. flabellifolia Pohl. presented favorable results with 0.05 and 0.025 mg L-1 NAA, respectively. Culture medium lacking NAA and BAP favored the in vitro growth of M. pseudoglaziovii Pax & Hoff.

Abscisic acid and in vitro conservation of Manihot wild species / Abscisic acid and in vitro conservation of Manihot wild species

Abscisic acid (ABA) is associated with bud dormancy, leaf abscission, and germplasm growth inhibition in in vitro conservation. We evaluated the effects of ABA in four wild Manihot accessions and one cassava accession (M. esculenta Crantz) to refine in vitro conservation methods for these species. The experiment was performed at the Laboratory for Tissue Culture from Embrapa, Cruz das Almas, Bahia State, Brazil. The statistical design was completely random in a 5 × 5 factorial scheme [(5 ABA dosages (0, 0.25, 0.50, 0.75, and 1 mg L-1) and 5 Manihot species (M. pseudoglaziovii, M. tristis, M. flabellifolia, M. chlorosticta, and M. esculenta)], with 15 replicates. Mini-cuttings of 1 cm were used, each inoculated in 10 mL of modified Murashige and Skoog medium, solidified with Phytagel® (2.4 g L-1) containing the respective ABA dosages. Tubes containing these mini-cuttings were placed in a germplasm conservation room with an irradiance of 30 µmol m-2 s-1, temperature of 22 ± 1°C, and photoperiod of 12 hours. Plant height (cm), the number of living and senescent leaves, shoots, and mini-cuttings (1 cm), and fresh and dry weights of shoots and roots (mg) were evaluated after 150 days. Growth reduction was prominent in M. pseudoglaziovii, M. tristis, and M. flabellifolia during the in vitro conservation period. In the present study, the addition of ABA did not promote the expected re

Abscisic acid (ABA) is associated with bud dormancy, leaf abscission, and germplasm growth inhibition in in vitro conservation. We evaluated the effects of ABA in four wild Manihot accessions and one cassava accession (M. esculenta Crantz) to refine in vitro conservation methods for these species. The experiment was performed at the Laboratory for Tissue Culture from Embrapa, Cruz das Almas, Bahia State, Brazil. The statistical design was completely random in a 5 × 5 factorial scheme [(5 ABA dosages (0, 0.25, 0.50, 0.75, and 1 mg L-1) and 5 Manihot species (M. pseudoglaziovii, M. tristis, M. flabellifolia, M. chlorosticta, and M. esculenta)], with 15 replicates. Mini-cuttings of 1 cm were used, each inoculated in 10 mL of modified Murashige and Skoog medium, solidified with Phytagel® (2.4 g L-1) containing the respective ABA dosages. Tubes containing these mini-cuttings were placed in a germplasm conservation room with an irradiance of 30 µmol m-2 s-1, temperature of 22 ± 1°C, and photoperiod of 12 hours. Plant height (cm), the number of living and senescent leaves, shoots, and mini-cuttings (1 cm), and fresh and dry weights of shoots and roots (mg) were evaluated after 150 days. Growth reduction was prominent in M. pseudoglaziovii, M. tristis, and M. flabellifolia during the in vitro conservation period. In the present study, the addition of ABA did not promote the expected re

Agronomic performance of cassava genotypes from the in vitro shoot tip culture submitted to clonal cleaning / Desempenho agronômico de genótipos de mandioca provenientes do cultivo in vitro de ápices caulinares submetidos à limpeza clonal

This study aimed to evaluate the agronomic performance of cassava genotypes from the in vitro shoot tip culture to eliminate the cassava frogskin disease for several root and aerial part characteristics. Cassava plants from accessions BGM0315, BGM0464 and BGM0841 infected with cassava frogskin disease were grown in a greenhouse after clonal cleaning. Cuttings from the three accessions were subjected to tetracycline concentrations (0, 5, 10 and 15 mg L-1) for three minutes, and then maintained in an acclimatized chamber (35 ± 1 °C and 16 hour photoperiod). Shoots were disinfected for excising shoot tips (0.2 mm and 0.4 mm) and inoculated in a culture medium containing the same concentrations of tetracycline used in the cuttings. After 60 days of cultivation, the explants were transferred to medium without antibiotic, 30 days later they were acclimatized for a period of 70 days for subsequent planting in the field. Seven months after planting, agronomical evaluation was held for root and aerial part characteristics. No influence of isolated shoot tip size was noticed on agronomic characteristics, while the addition of tetracycline in the culture medium, specifically at the concentrations of 5 mg L-1 and 15 mg L-1, was favorable to the development of the root system of plants in the field. The results revealed that the agronomic performance of cassava plants derived from in vitro cultivation are higher for the production of basic propagation material for the following production cycles, as well as root production for commercial use with subsequent generation of income.

Este trabalho teve por objetivo avaliar o desempenho agronômico de genótipos de mandioca provenientes do cultivo in vitro de ápices caulinares para eliminação da doença couro de sapo (Cassava frogskin disease, CFSD), em relação a diversas características de raiz e da parte aérea. Para isso, foram utilizadas plantas de mandioca dos acessos BGM0315, BGM0464 e BGM0841 cultivadas em casa de vegetação após a limpeza clonal. Inicialmente, foram utilizadas manivas de plantas adultas infectadas com couro de sapo. Essas manivas foram submetidas a concentrações de tetraciclina (0, 5, 10 e 15 mg L-1) por 3 minutos. Posteriormente, foram mantidas em câmara climatizada (35 ± 1°C e fotoperíodo de 16 horas). Brotos foram desinfestados para excisão de ápices caulinares (0,2 mm e 0,4 mm) e inoculados em meio de cultura contendo as mesmas concentrações de tetraciclina empregadas nas manivas. Aos 60 dias de cultivo, os explantes foram transferidos para meio sem antibiótico, 30 dias após foram aclimatizadas por um período de 70 dias para posterior plantio em campo. Aos sete meses após o plantio realizou-se a avaliação agronômica para características de raiz e parte aérea. Não houve influência do tamanho do ápice caulinar isoladamente nas características agronômicas avaliadas, enquanto que a adição de tetraciclina no meio de cultura, especificamente nas concentrações de 5 e 15 mg L-1, foi favorável ao desenvolvimento do sistema radicular das plantas no campo. Os resultados evidenciaram que o desempenho agronômico de plantas de mandioca provenientes do cultivo in vitro são elevados para produção de material propagativo básico para os ciclos seguintes de produção, bem como para produção de raízes para uso comercial com consequente geração de renda.

Somatic embryogenesis of Neoglaziovia variegata (Arruda) Mez, an important source of fiber from native Brazilian bromeliads

Neoglaziovia variegata (Arruda) Mez, a Bromeliad endemic to the Brazilian Caatinga and source of fiber for many different products, is considered an endangered species. Leaf and stem segments were cultivated on Murashige and Skoog (MS) medium with combinations of 2,4- dichlorophenoxyacetic acid (2,4-D) (0, 9, 18 and 27 µM) and glutamine (0, 50, 100, 150, 200 mg L-1) for the induction of embryogenic calli. Leaf segments did not present a favorable response for the combinations analyzed. The best response for embryogenic calli frequency with the best distribution of somatic embryos on the surface and better conversion rate was obtained using the stems explants in the medium containing 18 µM 2,4-D and 100 mg L-1 glutamine. The embryogenic calli obtained from the different induction media were transferred to MS medium supplemented with 30 g.L-1 sucrose, 2.4 g.L-1 Phytagel®, 0.53 µM α-naphthalene acetic acid (NAA) and 0.88 µM of 6-benzylaminopurine (BAP). The regenerated plants presented normal growth; however, many embryos did not fully develop.

Micropropagation and in vitro conservation of Neoglaziovia variegata (Arr. Cam.) mez, a fiber producing bromeliad from Brazil

Neoglaziovia variegata (Arr. Cam.) Mez is a Bromeliaceae native to the Caatinga, used for fiber extraction in the Northeast Region of Brazil. The antropic activity has place this species among the threatened ones. The objective of the work was to establish an in vitro propagation and conservation of caroá. Seeds were cultivated in MS medium in the presence or absence of light. In vitro germinated seedlings were multiplied in MS medium supplemented with the combinations 0.05 and 0.50 µM NAA and 2.2 and 4.4 µM BAP and KIN. The best percentages of germination were obtained with the seeds incubated in the presence of light. The highest multiplication ratio was obtained for the NAA (0,5 µM) + BAP (4,4 µM) treatment and the number of roots, with NAA (0.5 µM) + KIN (2.2 µM). Plant acclimatization presented differentiated results regarding the substrates tested. The conservation was established.

Neoglaziovia variegata é uma Bromeliaceae nativa da Caatinga, usada para extração de fibras na Região Nordeste do Brasil. A atividade antrópica coloca esta espécie entre as ameaçadas. O objetivo deste trabalho foi estabelecer uma propagação e conservação in vitro de caroá. Foram cultivadas sementes em meio MS na presença ou ausência de luz. Plântulas germinadas in vitro foram multiplicadas em meio MS suplementado com as combinações de 0,05 e 0.50 µM de NAA e 2.2 e 4.4 µM de BAP e KIN. Foram obtidas as melhores porcentagens de germinação com sementes incubadas na presença de luz. A taxa de multiplicação mais alta foi obtida no tratamento NAA (0,5 µM) + BAP (4,4 µM) e, o número de raízes, com NAA (0.5 µM) + KIN (2.2 µM). Aclimatização das plantas apresentou resultados diferenciados em relação aos substratos testados. A conservação foi estabelecida.

Morphogenetic response of cotyledon and leaf explants of melon ( Cucumis melo L. ) cv. Amarillo Oro

Explantes de cotilédones e folhas do cultivar de melão Amarillo Oro foram cultivados para avaliação do potencial morfogenético em diferentes meios de cultura com diversas concentrações de ácido indolacético (AIA), em combinação com 1,0 mg.L-1 benziladenina (BA) e 6,0 mg.L-1 de cinetina (CIN). Os melhores resultados foram obtidos com explantes de cotilédones, sendo que explantes de folhas mostraram uma capacidade baixa na indução de gemas. A variação na resposta organogênica em cotilédones de diferentes idades fisiológicas (1, 3, 5 e 7 dias após a germinação) mostraram que os melhores resultados foram obtidos com cotilédones de sete dias cultivados no meio MS suplementado com 1,5 mg.L-1 de AIA e 1,0 mg.L-1 de BA. O efeito do tipo de corte na resposta organogênica de explantes cotiledonares foi também avaliado. Os melhores resultados foram obtidos com explantes cortados transversalmente. Adição suplementar de sulfato de cobre ao meio de cultura resultou em uma melhora na qualidade da dos brotos regenerados.