Evaluation of Australian wheat genotypes for response to variable nitrogen application

Abstract

Aims The key aim was to assess the genetic variation for nitrogen (N) response and stability in spring wheat germplasm to determine the scope for improvement of nitrogen use efficiency (NUE) under water-limited, low yielding conditions. A further aim was to evaluate NUE stability and NUE-protein yield (PY) as suitable NUErelated traits for selection. Methods The traits measured included grain yield (GY, kg ha) and NUE (kg GY kg −1 N) under varying N applications at all sites, and NUE for protein yield (NUE-PY), harvest index and plant height at some sites.In addition, two of the trials used two seeding rates to provide an assessment of the impact of plant density on NUE.Results Genetic variation was significant for all traits studied. Grain yield was affected by both genotype (G) and N rate and the interaction between the two. Interestingly, harvest index and height showed no direct response to varying N applications. However, for these traits, there was a significant G effect and N response (G × N interaction).Conclusions Increasing N inputs led to variable responses for GY at different sites. Importantly, genetic variation in N response was detected. The information and screening techniques will enable plant breeders to select wheat genotypes that show a consistent response to high N. There is clear scope to improve NUE in spring wheat grown in low yielding environments.

Genotypic variation and stability for nitrogen use efficiency in winter wheat

“…Generally, wheat lines that expressed the highest mean grain yields in each study were also among the most stable within each of the three studies. Similar findings were reported in a panel of 25 spring barley ( Hordeum vulgare L.) varieties by Anbessa et al () and eight wheat lines by Mahjourimajd et al () who reported that the most stable lines generally experienced lower grain yield reduction between high‐ and low‐N conditions than did the least stable lines. The present investigation also found significant variation in the adaptability of wheat lines over and within specific N environments, indicating the existence of genotypic variation in broad vs. specific adaptability to both favorable and unfavorable environments.…”

“…Generally, wheat lines that expressed the highest mean grain yields in each study were also among the most stable within each of the three studies. Similar findings were reported in a panel of 25 spring barley (Hordeum vulgare L.) varieties by Anbessa et al (2009) and eight wheat lines by Mahjourimajd et al (2016) who reported that the most stable lines generally experienced Crop Science T A B L E 9 Correlation matrix for phenotypic traits in Study III at two N rates over six environments. Grain yield, grain protein yield (GPY), aboveground biomass (AGBM), harvest index (HI), grain N concentration (GNC), N uptake efficiency (NUpE) lower grain yield reduction between high-and low-N conditions than did the least stable lines.…”

“…In the present studies, G × N rate interactions for grain yield were most commonly observed when lines were tested under three or five N rates. Although exceptions exist (Kubota et al, 2018;Russell et al, 2017), recent investigations of NUE in wheat generally follow a similar trend where significant interactions between wheat genotype and N rate for grain yield were more frequently reported when more than two N rates were used (Barraclough et al, 2010;Büchi et al, 2016;Gaju et al, 2011;Guttieri, Frels, Regassa, Waters, & Baen-ziger, 2017;Latshaw et al, 2016;Mahjourimajd et al, 2016;Ul-Allah et al, 2018). These findings have led many breeders to advocate for direct selection of NUE under reduced N systems in locations that are subjected to N stress each growing season (Brancourt-Hulmel et al, 2005;Cormier et al, 2013;Muellner et al, 2014;Ranjitha et al, 2018).…”

Opposite fates of the purine metabolite allantoin under water and nitrogen limitations in bread wheat

“…RAC875 (RAC655/3/ Sr21/4*LANCE//4*BAYONET) is high-yielding in the drought and heat-prone South Australian environments (Izanloo et al 2008;Bennett et al 2012). Mace (WYALK-ATCHEM/STYLET//WYALKATCHEM) was bred and released by Australian Grain Technologies (AGT) in 2008 and preliminary studies suggest that Mace has high N-use efficiency across different South Australian environments (Mahjourimajd et al 2016).…”

The Genetics of Nitrogen Use Efficiency in Crop Plants

“…However, the challenges have been the degree of phenotypic variation for this complex trait and the difficulty in getting reliable data from field trial studies (80). There are now better statistical tools for molecular mapping, and the need for more careful experimental design and replicate testing has been recognized (90,119).…”