Assessment of Chemical Composition From Progenies of Alfalfa Down-Regulated In Lignin Biosynthesis.

Lignin content in alfalfa plays a pivotal role in determining forage quality and conversion efficiency of plant biomass to bioethanol. Genetic modification of lignin biosynthesis in alfalfa improves conversion efficiency for bioethanol production.  However, improvements in bioprocessing properties in alfalfa may be accompanied by alterations in plant height and productivity.  The objective of this study is to identify reduced lignin alfalfa lines with improved bioprocessing efficiency and good agronomic performance.  Independent crosses of a common male-sterile alfalfa with transformed alfalfa lines independently down-regulated in key enzymatic steps of the monolignol biosynthetic pathway produced full-sib T1 progenies segregating for lignin content.  The pipeline for screening plants includes Southern analysis in the T0 plants to identify insert copy number and PCR to determine the presence of the transgene in each of the progenies.  The segregating T1 progenies were evaluated in the greenhouse and field conditions in Ardmore, Oklahoma for their lignin content and composition, forage quality, biomass production, bioprocessing efficiency, agronomic and physiological characteristics. These findings will enable us to capture the full value of lignin modification technology by developing strategies that incorporate yield enhancement into plants with changes in cell wall chemistry.