title: A Substantial Fraction of Barley (Hordeum vulgare L.) Low Phytic Acid Mutations Have Little or No Effect on Yield across Diverse Production Environments.
abstract: The potential benefits of the low phytic acid (lpa) seed trait for human and animal nutrition, and for phosphorus management in non-ruminant animal production, are well documented. However, in many cases the lpa trait is associated with impaired seed or plant performance, resulting in reduced yield. This has given rise to the perception that the lpa trait is tightly correlated with reduced yield in diverse crop species. Here we report a powerful test of this correlation. We measured grain yield in lines homozygous for each of six barley (Hordeum vulgare L.) lpa mutations that greatly differ in their seed phytic acid levels. Performance comparisons were between sibling wild-type and mutant lines obtained following backcrossing, and across two years in five Idaho (USA) locations that greatly differ in crop yield potential. We found that one lpa mutation (Hvlpa1-1) had no detectable effect on yield and a second (Hvlpa4-1) resulted in yield losses of only 3.5%, across all locations. When comparing yields in three relatively non-stressful production environments, at least three lpa mutations (Hvlpa1-1, Hvlpa3-1, and Hvlpa4-1) typically had yields similar to or within 5% of the wild-type sibling isoline. Therefore in the case of barley, lpa mutations can be readily identified that when simply incorporated into a cultivar result in adequately performing lines, even with no additional breeding for performance within the lpa line. In conclusion, while some barley lpa mutations do impact field performance, a substantial fraction appears to have little or no effect on yield.
authors.affiliation: USDA-ARS Small Grains and Potato Research Unit, 1600 South 2700 West, Aberdeen, ID 83210, USA. victor.raboy@ars.usda.gov.
authors.forename: Victor
authors.initials: V
authors.lastname: Raboy
authors.affiliation: USDA-ARS Small Grains and Potato Research Unit, 1600 South 2700 West, Aberdeen, ID 83210, USA. Peterson.kevin1@mayo.edu.
authors.forename: Kevin
authors.initials: K
authors.lastname: Peterson
authors.affiliation: Idaho Falls Research and Extension Center, University of Idaho, 1776 Science Center Drive, Suite 205, Idaho Falls, ID 83402, USA. chadj@uidaho.edu.
authors.forename: Chad
authors.initials: C
authors.lastname: Jackson
authors.affiliation: Idaho Falls Research and Extension Center, University of Idaho, 1776 Science Center Drive, Suite 205, Idaho Falls, ID 83402, USA. jmarshall@uidaho.edu.
authors.forename: Juliet M
authors.initials: JM
authors.lastname: Marshall
authors.affiliation: USDA-ARS Small Grains and Potato Research Unit, 1600 South 2700 West, Aberdeen, ID 83210, USA. Gongshe.hu@ars.usda.gov.
authors.forename: Gongshe
authors.initials: G
authors.lastname: Hu
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8528, Japan. saneoka@hiroshima-u.ac.jp.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Saneoka
authors.affiliation: USDA-ARS Small Grains and Potato Research Unit, 1600 South 2700 West, Aberdeen, ID 83210, USA. phil.bregitzer@ars.usda.gov.
authors.forename: Phil
authors.initials: P
authors.lastname: Bregitzer
keywords: Hordeum vulgare; barley; grain yield; low phytic acid