Valeur nutritive, rendement, persistance et rentabilité de cultivars de luzerne (Medicago sativa L.) plus digestibles récoltés à différents stades de développement sous les conditions bioclimatiques du Québec
|Advisor:||Halde, Caroline; Tremblay, Gaëtan|
|Abstract:||Conventionally selected or genetically modified (GM) alfalfa (Medicago sativa L.) cultivars with improved digestibility are used in Quebec. The objective of the project was to compare the yield, nutritive value, winter survival, and profitability of more digestible alfalfa cultivars grown under two cutting intervals in Quebec. Eight cultivars were evaluated: two GM; four conventionally selected, two with low lignin concentration, one with high pectin concentration, and one with improved enzymatic stem degradability; and two controls. Each cultivar was harvested at the early bud stage or at less than 10% bloom at three sites. All cultivars survived the winter conditions well. In the first post-seeding year, the cultivars had an annual yield comparable to control cultivars, except for the cultivar selected for improved stem degradability (-13%). Both GM cultivars had an in vitro neutral detergent fiber digestibility (NDFd) that was 4.7% unit higher and a concentration of neutral detergent fiber, essayed with a heat stable amylase and sodium sulfite (aNDF), 1.0% unit lower than that of the controls. The conventionally selected cultivars had NDFd similar to that of the controls. The GM cultivars offered greater flexibility in harvesting. The extensively managed GM cultivars had a similar NDFd, a lower CP (-3.1% units), greater aNDF (+5.6% units) and acid detergent lignin (+0.16% units) concentrations, but an annual yield 1.0 Mg ha?1 higher than the intensively managed control cultivars, despite being harvested once less. The use of GM alfalfa cultivars can provide greater harvest flexibility, increase forage diet digestibility, and thus potentially improve cow feed efficiency.|
|Document Type:||Mémoire de maîtrise|
|Open Access Date:||8 November 2021|
|Collection:||Thèses et mémoires|
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