RESUMEN

In vitro germplasm conservation allows to extend the interval between subcultures without compromising the viability and genetic integrity of the plant, ensuring a backup of genotypes with high phytosanitary quality. Thus, this study aimed to verify the effect of four concentrations of Paclobutrazol® in inducing minimum growth in five Manihot esculenta accessions from the in vitro Active Germplasm Bank of Embrapa Cassava and Fruits. An experiment was installed using the Murashige and Skoog medium without addition and added with four concentrations of Paclobutrazol® (0.10, 0.20, 0.30, and 0.40 mg L-1), in five in vitro accessions of M. esculenta: BRS Jari (BGM 2041), Cigana (BGM 0264), BRS Poti Branca (BGM 2017), TME 14, and BRS Novo Horizonte. The statistical design was completely randomized in a 5 x 5 factorial scheme, with 15 repetitions. After 120 days of cultivation, the following variables were evaluated: plant height (cm), number of green leaves, number of senescent leaves, number of mini-cuttings, number of shoots, and fresh and dry mass of shoots and roots (mg). Paclobutrazol® caused a reduction in plant height and gain in root mass for all accessions, in addition to preserving the number of green leaves and decreasing leaf senescence for most genotypes. There was a strong dependence of the genotype in relation to the concentration of Paclobutrazol®. The concentration of 0.20 mg L-1 showed potential in the in vitro conservation of M. esculenta genotypes.(AU)

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RESUMEN

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 reduction in plant growth.(AU)

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RESUMEN

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.(AU)

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

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