Evaluation of cassava plants generated by somatic embryogenesis at different stages of development using molecular markers

Background: Cassava (Manihot esculenta Crantz) is a crop that is high in carbohydrates in the roots and in protein in the leaves, important for both human consumption and animal feed, and also has a significant industrial use for its starches. In this study we evaluated the genetic variability with molecular markers in different stages in micropropagated plants from somatic embryos of Venezuelan native clone 56. Results: Three markers were used: ISTR, AFLP and SSR, finding that ISTR showed the highest polymorphism among individuals tested. With AFLP a high similarity between the evaluated individuals was observed and with SSR total monomorphism was seen. Using cluster analysis it was found that individuals from an embryo labeled as fasciated at the beginning of the somatic embryogenesis process were grouped as independent of the other plants when analyzed at the acclimatization stage. The differences found with the different markers used are discussed. In field trials, micropropagated plants had a yield between 4 and 5 times the average yield of cassava in Venezuela. Conclusion: Despite variability in terms of DNA markers, somatic embryogenesis is suitable for mass propagation of highly performing cassava clones.

A magnetized jet from a massive protostar.

Synchrotron emission is commonly found in relativistic jets from active galactic nuclei (AGNs) and microquasars, but so far its presence in jets from young stellar objects (YSOs) has not been proved. Here, we present evidence of polarized synchrotron emission arising from the jet of a YSO. The apparent magnetic field, with strength of ~0.2 milligauss, is parallel to the jet axis, and the polarization degree increases toward the jet edges, as expected for a confining helical magnetic field configuration. These characteristics are similar to those found in AGN jets, hinting at a common origin of all astrophysical jets.