Relative Date of Wheat Seedling Emergence and Its Impact on Grain Yield

Abstract

Emergence of wheat (Triticum aestivum L.) seedlings usually occurs over a period of several days, resulting in nonuniformity among neighboring plants. The impact of nonuniformity in time of emergence on grain yield has not been determined. We determined effect of planting depth on relative date of seedling emergence, and of relative date of emergence on grain‐bearing tillers and grain yield per plant. Large seed (39.8 ± 4.59 mg kernel−1) in 1989, and large (41.7 ± 3.83 mg kernel−1) and small seeds (24.3 ± 4.56 mg kernel−1) in 1990 were obtained from ‘Roblin’ wheat. Seeds were hand.planted at 25‐, 50‐, and 75‐mm depths on Neuborst clay loam (fine‐loamy, frigid, Aquic Haploborolls) at Portage la Prairie, MB. Plants were tagged the day they emerged, and individual plant yield was determined at harvest. Planting depths did not differ for total percent emergence in 1989, but in 1990, increasing planting depth led to decreased total emergence. Gompertz growth model predictions of inflection time, maximum emergence rate, and cumulative percent emergence indicated that seedling emergence rate decreased as planting depth increased, and the decrease was greater with small seed than with large seed. The first date on which seedlings emerged each year was designated as Day 1. Averaged across 2 yr, plants that emerged on Day 1 to 3 produced 1.4 times the yield of those emerged on Day 4 to 6, and 3.2 times the yield of those emerged on Day 7 to 9. Reduced yield of late emerged plants was due primarily to fewer grain‐bearing tillers. This research demonstrates the benefit of shallow placement of large seeds in minimizing variation in time of seedling emergence among plants, and increasing grain yield.

Longer coleoptiles improve emergence through crop residues to increase seedling number and biomass in wheat (Triticum aestivum L.)

“…By contrast, increasing stubble mass and sowing depth slowed seedling emergence and reduced tiller number to reduce seedling biomass, as observed in the field. Delayed seedling emergence has been reported to reduce seedling leaf area and biomass, tiller number per plant and spike number per unit area, grain yield and total biomass in wheat (Hadjichristodoulou et al, 1977;Gan et al, 1992;Mahdi et al, 1998). Poor leaf area development can lead to increased competition by weeds (Coleman et al, 2001), and greater soil evaporation to reduce crop water use effi- Values in parenthesis represent change relative to the optimal 0 t/ha, 50 mm sowing depth.…”

Seed quality effects on seedling emergence, plant stand establishment and grain yield in two-row barley

“…These two traits are affected by several factors, starting from grain-filling period and continuing throughout harvest and storage conditions. Seed age, moisture content, infection by seed-borne pathogens and seed weight are among the characteristics associated with seed viability and vigour (Doling 1968, Ching et al 1977, Khah et al 1989, Gan et al 1992, Chastain et al 1995, Grilli et al 1995, Reddy et al 1999, Nonogaki et al 2010. Differences between germination rates in the laboratory and seedling emergence rates in the field may vary considerably: seed lots with a germination rate of 85-100% produced seedlings at rates of 47 to 93% according to Steiner et al (1989).…”

Response to selection, combining ability and heritability of coleoptile length in winter wheat

“…Emergence from deep sowing typically results in fewer, later emerging plants (Gan et al 1992). Allan et al (1962) developed a field-based emergence rate index to quantify the impact of the various traits that influence emergence, including coleoptile length, speed of emergence and plant height.…”