The Integration of Spring and Winter Wheat Genetics With Agronomy for Ultra-Early Planting Into Cold Soils

Abstract

Early seeding has been suggested as a method of increasing the grain yield and grain yield stability of wheat (Triticum aestivum L.) in the Northern Great Plains. The point at which early seeding results in a decrease in grain yield has not been clearly identified. Changes in climatic conditions have increased frost-free periods and increased temperatures during grain filling, which can either be taken advantage of or avoided by seeding earlier. Field trials were conducted in western Canada from 2015 to 2018 to evaluate an ultra-early wheat planting system based on soil temperature triggers as opposed to calendar dates. Planting began when soil temperatures at 5 cm depth reached 0°C and continued at 2°C intervals until 10°C, regardless of calendar date. Conventional commercial spring wheat genetics and newly identified cold tolerant spring wheat lines were evaluated to determine if ultra-early wheat seeding systems required further development of specialized varieties to maintain system stability. Ultra-early seeding resulted in no detrimental effect on grain yield. Grain yield increased at sites south of 51°latitude N, and was unaffected by ultraearly seeding at sites north of 51°latitude N. Grain protein content, kernel weight, and bulk density were not affected by ultra-early seeding. Optimal seeding time was identified between 2 and 6°C soil temperatures. A greater reduction in grain yield was observed from delaying planting until soils reached 10°C than from seeding into 0°C soils; this was despite extreme environmental conditions after initial seeding, including air temperatures as low as −10.2°C, and as many as 37 nights with air temperatures below 0°C. Wheat emergence ranged from 55 to 70%, and heads m −2 decreased with delayed seeding while heads plant −1 did not change. Cold tolerant wheat lines did not increase stability of the ultra-early wheat seeding system relative to the conventional spring wheat check, and are therefore not required for growers to adopt ultra-early seeding. The results of this study indicate that growers in western Canada can successfully begin seeding wheat earlier, with few changes to their current management practices, and endure less risk than delaying seeding until soil temperatures reach 10°C or greater.

A Systematic Review of Durum Wheat: Enhancing Production Systems by Exploring Genotype, Environment, and Management (G × E × M) Synergies

“…Durum wheat yield losses in Australia are primarily due to water stress (Liu et al, 2015) similar to well-published studies in wheat from lack of rainfall during spring which causes a mild water deficit stress prior to anthesis, moderate stress at anthesis and becomes more severe during grain fill (French and Schultz, 1984). Agronomic solutions to maintain yield and reduce potential exposure to water stress, heat and frost can be achieved by manipulating plant development and sowing date (Bassu et al, 2009;Collier et al, 2020). To facilitate the timing of optimal flowering, growers need to match a genotype development speed with sowing date.…”

“…The authors report that grain yield was not compromised and often maximized when seeding occurred at around 2 o C soil temperature. A greater reduction in grain yield was observed when planting was delayed until soil reach 10 o C, despite extreme environmental conditions after initial seeding, including air temperatures as low as −10.2 o C and as many as 37 nights with air temperatures below 0 o C (Collier et al, 2020). An opportunity associated with such a system that results in earlier maturity is a refined integrated pest management strategy.…”

“…For example, one major pest of durum wheat is the orange wheat blossom midge, which attacks wheat during anthesis. An ultra-early planting strategy using soil temperature as a trigger facilitates an asynchrony between the vulnerable host plant phenological stage and the primary window of pest infestation (Collier et al, 2020). The same management strategy is used by producers to mitigate FHB infection such that earlier flowering coincides with less optimal environment conditions for fungal infection.…”

Optimal Agronomics Increase Grain Yield and Grain Yield Stability of Ultra-Early Wheat Seeding Systems

“…A short frost-free period is commonly referenced as a grain yield-limiting factor on the northern Great Plains; however, increases in the average frost-free period from 1961 to 2018 are rarely referenced as contributing to wheat grain yield increase [4][5][6][7]. Ultra-early wheat seeding systems based on soil temperature triggers as described in Collier et al [8] can produce greater grain yield by capturing the benefits of longer frost-free periods: early season growing degree-day accumulation, increased vegetative growth periods, early season precipitation, increased day-length at anthesis and reduced average temperatures at grain fill.…”

“…Studies investigating wheat and small grain cereals seeding dates reported the greatest yield resulted from the earliest seeding dates [15][16][17][18][19]. However, these studies initiated plantings based on an arbitrary calendar date, meaning the planting times within individual seasons were not standardized to account for variability between growing seasons, an issue accounted for by moving to soil temperature-triggered seeding in the study conducted by Collier et al [8]. Multiple studies have identified earlier seeding as an important method to avoid grain yield reduction caused by increased growing season temperatures [8,14,20,21].…”