Genetic diversity among homonymy accessions maintained in the cassava regional Brazilian genebank.

In the Amazon region, the cassava cultivation has great social and economic importance because its production is source of food for traditional population and income for small farmers. The cassava farmer fields are results of the tradition and the preference of consumption and represent the genetic variability of many characters related to the mode of use and the quality of cassava root. The identification of genotypes to generate improved clones has been supported by germplasm conservation, evaluation and molecular characterization

Genetic diversity of cassava accessions from two regions of Amazon State, Brazil.

The study aimed to assess the genetic diversity of accessions collected in two regions from Amazon State, 120 from Lower Amazon River and 120 from Madeira River, using Inter Single Sequence Repeats (ISSR) markers

Germinação in vitro de embriões do híbrido dendezeiro (E. guineensis) x caiaué (E. oleifera).

O objetivo deste trabalho foi testar condições para a germinação in vitro dos embriões híbridos

Soil fertility levels in the process of recovery of degraded pasture by iCL in the western Brazilian Amazon.

This study aimed to compare the soil fertility levels in degraded pastures and in the recovery process with iCL

In vitro rescue of interspecific embryos from Elaeis guineensis x E. oleifera (Arecaceae).

The African oil palm (Elaeis guineensis) is the most effective oil producer in tons per hectare. Nevertheless, its increasing cultivation in Latin America is harmed by the lethal yellowing. Genetic resistance to this anomaly can be found in the germplasm of American oil palm or caiaué (E. oleifera), a native species from the Amazon rainforest. However, the procedures adopted to induce seeds of E. guineensis to germination frequently result mild for interespecific hybrids. Embryo in vitro cultivation can be a viable option. This work was aimed initially to test liquid MS medium supplemented with different glucose or sucrose concentrations for the in vitro cultivation of zygotic embryos from E. guineensis x E. oleifera controlled pollinations. Additionally we investigated different compost mixtures to acclimatize the regenerated hybrid plantlets. Concentrations of 10, 20 and 30g/L of both sugars were tested on flasks containing five mature zygotic embryos, with 15 repetitions per treatment in a total of 450 explants. The number of embryos displaying shoots and radicles at least 2mm in length per experimental unit was evaluated during phase one of in vitro cultivation. Plantlets displaying shoots and radicles were transferred to phase two of in vitro cultivation and subsequently to acclimatization, under 70% shading with manual water supply. The experiments of acclimatization were conducted with 130 plantlets randomly distributed in pure horticultural compost, 3:1 or 1:1 compost:sand mixtures and each plantlet was defined as an experimental unit. Data were submitted to ANOVA, t test and analyzes of correlation (p?0.05). Highest emergence rates were 97% for shoots and 73% for radicles, observed in MS medium supplemented with 20g/L (110mM) of glucose. This sugar in concentrations of 20 or 30g/L provided balanced shoot/root development, and this was considered one of the reasons for the higher frequency of plantlet establishment. The survival percentage was 55% after the first 43 days of acclimatization and by the fourth month, 66 plants developed simultaneously longer shoot and root systems in pure horticultural compost. In conclusion, radicle development was an impairment to plantlet establishment and was overcame under media with glucose above 110mM. Acclimatization could benefit from an extended period of in vitro development

In vitro rescue of interspecific embryos from Elaeis guineensis x E. oleifera (Arecaceae).

This work was aimed initially to test liquid MS medium supplemented with different glucose or sucrose concentrations for the in vitro cultivation of zygotic embryos from E. guineensis x E. oleifera controlled pollinations. Additionally we investigated different compost mixtures to acclimatize the regenerated hybrid plantlets