Evaluation of growth and nitrogen fixation of pea nodulation mutants in western Canada

Optimized biological nitrogen fixation (BNF) in pea (Pisum sativum L.) could increase crop productivity and reduce nitrogen fertilizer use in Western Canada. We tested the BNF capabilities and growth of three pea nodulation mutants (Frisson P64 Sym29, Frisson P88 Sym28 and Rondo-nod3 (fix+)) compared to check cultivars (CDC Dakota, CDC Meadow, Frisson, Rondo and non-fixing negative control Frisson P56 (nod-)) under field conditions in Saskatchewan, Canada, in three environments. CDC Meadow and CDC Dakota produced greater dry biomass and seed yield, but less fixed nitrogen compared to the mutants. On average, Frisson P88 Sym29 fixed 19% and 31% more nitrogen per plot compared to CDC Dakota and CDC Meadow, respectively. Rondo-nod3 (fix+) fixed 12% and 23% more nitrogen per plot compared to CDC Dakota and CDC Meadow, respectively. All lines grown at Saskatoon in 2015 had longer time to flowering, greater biomass, greater grain yield, but less amount of nitrogen fixation compared to these lines grown at Saskatoon in 2014 or Floral in 2015. Compared to the commercial checks, Frisson P88 Sym29 and Rondo-nod3 (fix+) had a high % nitrogen derived from atmosphere (Ndfa) and good nodulation under relatively high soil available nitrogen content, while requiring at least one week shorter growing period to reach maturity, indicating these mutants have potential as parents in breeding for improved BNF in pea.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author