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Multi-State Evaluation of Reduced Lignin Alfalfa Forage Nutritive Value and Yield

Parker, Angela
http://rave.ohiolink.edu/etdc/view?acc_num=osu1514908461145403

Abstract Details

2018, Master of Science, Ohio State University, Horticulture and Crop Science.
Alfalfa (Medicago sativa L.) is grown worldwide and used fundamentally to meet the nutritional requirements by primarily ruminant livestock. However, nutritive value of alfalfa is severely limited by indigestible cell wall constituents, such as lignin. There have been many efforts to improve alfalfa digestibility by down regulating enzymes in lignin pathways to develop alfalfa with reduced lignin (RL) content. In 2015, RL cultivars were released for commercial use. The purpose of this research was to: 1) compare forage nutritive value and yield of a RL cultivar (HarvXtra) to non-RL cultivars and 2) to determine if a recalibration of the predictive equations for alfalfa quality (PEAQ) was necessary for adequate neutral detergent fiber (NDF) predictions for RL alfalfa. This research was established in six states across the USA in 2015 and continued until spring of 2017 for Objective one. Plant sampling for Objective two occurred in Ohio and Wisconsin in 2016. The experimental design was a randomized complete-block with a split plot restriction on treatment randomization, where harvest intervals (28-, 33-, and 38-day) were the whole plot factor and cultivar was the sub plot factor. For Objective one, the overall linear model for cultivar response to harvest intervals was significant and all cultivars responded similarly across harvest intervals and events. Reduced lignin alfalfa, `HarvXtra-008’ always had higher nutritive value than non-RL cultivars. Neutral detergent fiber digestibility (NDFD) for `HarvXtra-008’ was greater (P<0.05) by 4.0 to 10.4% (21 to 49 g kg-1 actual NDFD units) than non-RL cultivars. The NDF was lower (P<0.05) for `HarvXtra-008’ by 5.4 to 8.3% units than `P54R02’. Differences in yield at individual harvests among cultivars and across harvest intervals were non-significant; however, `HarvXtra-008’ lower (P<0.05) in annual total dry matter yield than non-RL cultivars. For Objective two, the PEAQ NDF prediction was calculated from the stage of the most mature stem (MAX) and the height of the tallest stem in each sample (MAXHT) during each regrowth period. The observed near infrared reflectance spectroscopy (NIRS) values were regressed on the estimated PEAQ values. Across both states and all cuttings, root mean square error (RMSE) for all three alfalfa cultivars ranged from 25.2 to 31.8 g kg-1 for NDF and the coefficient of determination (r2) ranged from 0.60 to 0.71. When regressions were conducted on cultivar means across four replicates, RMSE ranged from 17.2 to 27.5 g kg-1; the coefficient of determination also improved ranging from 0.69 to 0.83. The slopes and intercepts were tested and were not significantly different among cultivars, but the Wisconsin regressions differed from Ohio regressions. Based on the results from these studies, `HarvXtra-008’ always had higher nutritive value within any given harvest interval, and yield within harvest interval was not different from non-RL alfalfa. Furthermore, it can be harvested 5 to 10 days later and still have similar to better nutritive value and similar yield as non-RL cultivars harvested earlier, suggesting that alfalfa producers have more flexibility with RL alfalfa when making harvest timing decisions. The original PEAQ equations were acceptable for predicting forage NDF in the RL alfalfa cultivar we tested.
R. Mark Sulc (Advisor)
David Barker (Committee Member)
Maurice Eastridge (Committee Member)
Edzard van Santen (Committee Member)
143 p.
Agronomy
Reduced Lignin Alfafla

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Citations

  • Parker, A. (2018). Multi-State Evaluation of Reduced Lignin Alfalfa Forage Nutritive Value and Yield [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1514908461145403

    APA Style (7th edition)

  • Parker, Angela. Multi-State Evaluation of Reduced Lignin Alfalfa Forage Nutritive Value and Yield. 2018. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1514908461145403.

    MLA Style (8th edition)

  • Parker, Angela. "Multi-State Evaluation of Reduced Lignin Alfalfa Forage Nutritive Value and Yield." Master's thesis, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1514908461145403

    Chicago Manual of Style (17th edition)

osu1514908461145403
428
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