Journal of Fundamentals of Renewable Energy and Applications
Open Access
ISSN: 2090-4541
+44 1300 500008
ISSN: 2090-4541
+44 1300 500008
Annick Bertrand
Scientific Tracks Abstracts: J Fundam Renewable Energy Appl
Alfalfa (Medicago sativa L.) has a high potential for sustainable bioethanol production. Genetic improvement for the
saccharification of structural carbohydrates could significantly increase ethanol conversion rate. Genetic gains for this
trait are tributary to the availability of screening techniques for the precise identification of superior genotypes. We developed
an efficient enzymatic assay to measure alfalfa stem saccharification, based on the quantity of glucose released by a customized
commercially available enzyme cocktail. Using that new assay, we observed a large genetic diversity for saccharification within
and among cultivars. To increase the analytical throughput, we used near-infrared reflectance spectroscopy (NIRS) to predict
cell wall (CW) saccharification in hundreds of lignified stem samples. Twenty (20) genotypes with high (S+) and 20 genotypes
with low (S-) saccharification (S) expressed as the levels of enzyme-released glucose were selected within each of abiomass-type
(Orca) and a winter hardy-type (54V54) cultivar. These genotypes were intercrossed to generate a first cycle of recurrent selection
for high (S+1) and low (S-1) saccharification. Assessment of CW enzyme-released glucose after a second cycle of recurrent
phenotypic selection confirmed that this trait is genetically inherited. Populations recurrently selected for saccharification were
used to identify DNA polymorphisms associated with this trait using the sequence-related amplified polymorphism (SRAP)
PCR-based technique. Polymorphisms positively or negatively related to saccharification were identified in each genetic
background using a bulk analysis of pooled DNA (50 genotypes/population). Subsequent scoring of these polymorphisms
within each genetic backgroundled to the identification of genotypes that combine two or more polymorphisms associated to
saccharification. These elite genotypes were intercrossed to generate a first cycle of marker-assisted selection with potentially
higher saccharification (MAS S+1). A second cycle of MAS selection was performed to further increase the frequency of these
markers in MAS S+2 populations. Comparative assessment of populations obtained with phenotypic recurrent selection and
marker-assisted selection is underway to assess the complementarity of these new selection methodologies and establish their
performance for the development of populations with significantly higher ethanol conversion rates in alfalfa.
Annick Bertrand has internationally recognized expertise on physiology and biochemistry of perennial forage crops. She developed new selection methods for the
improvement of complex trait such as saccharification potential and abiotic stress resistance of perennials.