Harvxtra, Roundup Ready Reduced Lignin Alfalfa Yield and Forage Quality Trial in Southeast Idaho.

Digestibility decreases as alfalfa (Medicago sativa L.) matures due to increased lignin production. Lignin is a complex phenolic polymer that provides plant support. As plants mature forage yield increases and forage quality declines due to an increase in lignin content. Through genetic technology, the regulation of enzyme pathways that control lignin makes it possible to grow alfalfa varieties that limit lignin production throughout their life cycle. The result leads to higher digestibility determined by neutral detergent fiber digestibility (NDFD) analysis, and measured by relative forage quality (RFQ). This study compares quality changes overtime of  HarvXtra®, an experimental variety (HarvXtra-008), developed by Forage Genetics Int’l, to two commercial Roundup Ready® varieties (54R02 and WL 355RR). At harvest time (beginning 20 days after the last cut) one square foot sub-plots were sampled within 33 ft² plots at four day intervals to simulate 20-day up to 37-day cutting management systems (7 cut vs. 5 cut systems). Each harvest day, a new square foot section was sampled from within the plot as alfalfa matured. Comparison of HarvXtra was made to two non-low lignin Roundup Ready varieties to test whether Low Lignin (LL) alfalfa will maintain RFQ values over the duration of cutting frequencies.