Yield Data from the Uniform Southern Soft Red Winter Wheat Nursery Emphasize Importance of Selection Location and Environment for Cultivar Development

• Published in: Crop science 2019-09, Vol.59 (5), p.1887-1898
• Main Authors: Boyles, Richard E., Marshall, David S., Bockelman, Harold E.
• Format: Article
• Language: English
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2018.11.0685

Yield and agronomic data from a regional soft red winter wheat (Triticum aestivum L.) nursery—consisting of 604 advanced breeding lines (ABLs) and 36 testing locations over a 21‐yr period—were evaluated to understand recent genetic gains in wheat and determine the impact of selection location and environment on cultivar performance and adaptation. Relative mean yield improvement of ABLs with respect to historical cultivar AGS 2000 was 106 kg ha−1 yr−1 (1.58 bu acre−1 yr−1), equating to an annual genetic gain of 1.6%. Yield gains for wheat during this timespan were attributed to an increase in both yield potential and stability across environments. However, a strong tradeoff (r = −0.36, p < 2.2 × 10−16) was observed between yield potential and stability. Additionally, distance between selection and evaluation environments was significantly correlated with yield, with yield decreasing as distance between locations increased. Advanced breeding lines had a +221, +126, and −29.6 kg ha−1 yr−1 (+3.29, +1.88, and −0.44 bu acre−1) yield difference over the location mean when the selection location was within, adjacent, and nonadjacent to the trial location zone, respectively. Advanced breeding lines in general performed poorly in production environments west of their selection site. Based on data analyzed, elevation and latitude are significant geographic parameters to consider when determining optimal selection location for a production environment. Meanwhile, change in growing degree days between selection and evaluation location had a stronger influence on yield than precipitation. Findings demonstrate the importance and benefits of breeder collaborations and multienvironment testing on crop improvement, which will be needed to maximize yield gains in the 21st century.