Sugarcane (Saccharum sp, Poaceae) is native to Southeast Asia, and due to growing demand as raw material, its cultivation recently expanded to new frontiers. The genetic diversity analysis is essential for targeting strategies in the formation and maintenance of a germplasm. This study aimed to assess the genetic diversity of 26 accessions of sugarcane from the Active Germplasm Bank of Embrapa Coastal Tablelands, using inter-simple sequence repeat (ISSR) molecular markers. Sixteen primers were used, resulting in 87 fragments with 91.13% of polymorphism. The similarity of the individuals ranged between 0.22 and 0.87. Individuals RB867515 and RB92579 were closer genetically, and the most distant ones were PI240785 and NSL 291970. Four distinct clusters were formed, using UPGMA. This information can be used to prioritize the selection of accessions for the conduction of hybridization in breeding and germplasm exchange actions.

Drought is the most limiting environmental factor to crop productivity and presents a great variability in the degree of tolerance among and within species, among varieties. The aim of this study was to characterize sugarcane accessions regarding tolerance to water stress during in vitro cultivation based on changes in biometric, physiological and biochemical characteristics, within species and among species, to support future breeding programs. Adventitious shoots of five sugarcane accessions: Saccharum robustum, Saccharum spontaneum and Saccharum officinarum species, cultivated in Murashige and Skoog medium supplemented with 2% sucrose and 4 g/l Phytagel were used in five water potentials, 0, -0.3, -0.6, -0.9, -1.2 MPa, induced by mannitol. Survival, length of shoots and roots, number of shoots and roots, biomass, proline content in leaves and activity of antioxidant enzymes were analyzed. There is difference among species, and also, within the same sugarcane species when submitted to in vitro drought stress, and S. officinarum was shown to be the most tolerant. Proline can be used as a biochemical indicator of response to drought in sugarcane accessions and its accumulation was intensified in S. robustum and S. spontaneum accessions. Catalase activity remained unchanged with increased drought in sugarcane accessions evaluated.

Hancornia speciosa Gomes, popularly known as mangaba tree, is a fruit tree native to Brazil, with natural occurrence in several regions. However, some factors have contributed to the reduction of natural populations of this species, in addition to the recalcitrant characteristic of its seeds, which hinders their storage for conservation purposes. The application of plant tissue culture techniques is a complementary strategy to the conservation of the existing genetic variability and allows Original Research Article

Azadirachta indica A. Juss, popularly known as neem, is a species native to India, belonging to family Meliaceae, considered the most important plant species with insecticidal action. The aim of this study was to evaluate the influence of growth regulators on induction and growth of neem callus and to observe their viability for embryogenesis through morpho-histological characteristics. In vitro germinated plants were used for excision of nodal explants. These segments were inoculated in Murashige and Skoog culture medium containing 1.0 mg/l 2,4-D (2,4-dichlorophenoxyacetic) combined with BAP (6-benzylaminopurine) at the following concentrations: 0.0, 0.5, 1.0 and 2.0 mg/l (T1, T2, T3 and T4 respectively), for callus induction. At 0 (mass of nodal segments without callus), 20, 40 and 60 days of culture, the percentage of callus formation was observed and the callus weight was measured for each treatment and at the end of the 60 days, consistency, color, and cell histology were evaluated. There was callus formation in all treatments tested. The highest induction of Azadirachta indica A. Juss callus is observed in the presence of 1.0 mg/l 2,4-D + 2.0 mg/l BAP, with callus showing light brown color, friable consistency and rounded cells with intense cell division, typical of cells with potential embryogenic capacity.

The aim of this study was to evaluate the in vitro morphogenic potential of genipap (Genipa americana L.) zygotic embryos. Seeds obtained from ripe fruits had their zygotic embryos excised and inoculated in MS medium with 4.44µM of 6-benzylaminopurine (BAP) and supplemented with 0.0; 1.07; 2.14 and 3.21µM of naphthalene acetic acid (NAA). The potential of explants regeneration and the shoot length and number of leaves in plantlets were evaluated. The in vitro regeneration of genipap is possible from the conversion of zygotic embryos in a MS medium with 4.44µM BAP supplemented with 3.21µM NAA.