Nitrogen Affects Seed Production Characteristics in Yellow Mustard

Core Ideas Applied N increased seed and oil yield in yellow mustard in a high rainfall environment. Seeds m −2 was the most influential factor in determining seed yield in yellow mustard. Applied N increased height, biomass, tissue N content, leaf area index, and crop growth rate.The response of applied N in yellow mustard ( Sinapis alba L.) seed production is unknown in the high rainfall environments of the Pacific Northwest. The objective of this study was to determine the effect of applied N on growth, seed yield, and oil production in yellow mustard in this unique environment. Trials were conducted over 3 yr near Corvallis, OR, on cultivar IdaGold yellow mustard with five N rates: 0, 56, 112, 168, and 224 kg N ha −1 . Growth and dry matter partitioning were measured at stem elongation (Biologische Bundesanstalt, Bundessortenamt und CHemische In [BBCH] 30), inflorescence emergence (BBCH 50), and harvest (BBCH 87). Applied N increased height, biomass, leaf area index (LAI), crop growth rate (CGR) and tissue N content. Although rainfall differed among years, N had similar effects on seed yield and yield components. Seed yield increases ranged from 15 to 85% with applied N, primarily as a result of N‐induced increases in seed weight and seed number. Yields ranged from 1010 kg ha −1 with 0 kg N ha −1 to 2579 kg ha −1 with 224 kg N ha −1 . Primary racemes plant −1 was positively associated with increased N. Siliques plant −1 increased with N rate and resulted from increased siliques production on mainstem and primary racemes. Seed oil content was inconsistently affected by N rate; however, highest oil yield was observed with 224 kg N ha −1 . This study will form the foundation for N recommendations for yellow mustard seed production in the Pacific Northwest.