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Natural Glyphosate Tolerance in Sainfoin ( Onybrychis viciifolia )
Author(s) -
Peel Michael D.,
Ransom Corey V.,
Mott Ivan W.
Publication year - 2013
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2012.10.0612
Subject(s) - biology , seedling , glyphosate , zoology , medicago sativa , agronomy , forage , horticulture , legume , glycine , amino acid , biochemistry
Sainfoin ( Onobrychis viciifolia Scop.), a nonbloating forage legume, is purported to have tolerance to glyphosate [ N ‐(phosphonomethyl) glycine]. The effect on biomass yield (BMY) and survival of eight rates of glyphosate on seedlings and mature plants were determined. Treatment rates were 0, 210, 420, 841, 1681, 3363, 6725, and 13,450 g ae ha −1 . Alfalfa ( Medicago sativa L.) was included as susceptible check. The dose required to produce a 50% reduction (GR 50 ) in sainfoin seedling BMY was 868 and 2984 g ae ha −1 at the first and second harvests, respectively. Alfalfa seedling BMY GR 50 values were 331 and 463 g ae ha −1 at the first and second harvests, respectively. The dose estimated to cause 50% mortality (LD 50 ) in sainfoin seedlings was beyond the highest treatment rate at 14,016 g ae ha −1 , compared with alfalfa at 2068 g ae ha −1 . Four weeks after a spring treatment, sainfoin and alfalfa mature plant BMY GR 50 values were 2622 and 208 g ae ha −1 , respectively. Biomass yield GR 15 values from the same spring treatment were 1030 g ae ha −1 for sainfoin and 66 g ae ha −1 for alfalfa. Thirteen months following the spring treatments sainfoin and alfalfa GR 50 values averaged 11,007 and 1093 g ae ha −1 , respectively. Fall applied glyphosate BMY GR 50 values from harvests the following spring were 12,949 g ae ha −1 for sainfoin and 755 g ae ha −1 for alfalfa. The LD 50 for sainfoin spring and fall treatments on mature plants was estimated to be well beyond the highest treatment rate 13,450 g ae ha −1 . The average LD 50 for mature alfalfa plants was 583 g ae ha −1 . Based on the LD 50 values, sainfoin seedlings are over six times more tolerant, and mature plants over 20 times more tolerant to glyphosate than alfalfa. Based on the GR 50 values, glyphosate has a 10‐fold greater negative impact on alfalfa BMY than it does on sainfoin; however, the GR 15 values indicate a likely reduction in sainfoin BMY at glyphosate rates in the range of 841 g ae ha −1 .