Author
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Pedersen, Jeffrey |
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Submitted to: Haworth Press
Publication Type: Other Publication Acceptance Date: 7/9/2001 Publication Date: 1/7/2003 Citation: PEDERSEN, J.F. REGRESSION OF FORAGE YIELD AGAINST A GROWTH INDEX AS A TOOL FOR INTERPRETATION OF MULTIPLE HARVEST DATA. HAWORTH PRESS. 2003. Interpretive Summary: Forage cultivars are often evaluated using multiple harvests throughout one or more growing seasons, and data summarized by presenting a yearly total yield for each cultivar in addition to the yield for each harvest date. Such data summarization becomes difficult to interpret as numbers of entries increase. Regressing yield against a growth index associated with harvest dates can be utilized to describe forage performance in a concise and easily interpreted format. A SAS program is provided that regresses yield of a cultivar against an index calculated as the mean of all entries at a harvest date minus the grand mean. The resulting regression coefficient describes cultivar yield response over several harvests and is indicative of performance under variable growth conditions. Technical Abstract: Forage cultivars are often evaluated using multiple harvests throughout one or more growing seasons, and data summarized by presenting a yearly total yield for each cultivar in addition to the yield for each harvest date. Such data summarization becomes difficult to interpret as numbers of entries increase. Regressing yield against a growth index associated with harvest dates can be utilized to describe forage performance in a concise and easily interpreted format. A SAS program is provided that regresses yield of a cultivar against an index calculated as the mean of all entries at a harvest date minus the grand mean. The resulting regression coefficient describes cultivar yield response over several harvests and is indicative of performance under variable growth conditions. |
