First Leaf Emergence Force of Three Deep‐Planted Winter Wheat Cultivars

Abstract

Late summer planting of winter wheat (Triticum aestivum L.) into tilled fallow is necessary for production of maximum yield in many areas of the low precipitation (<30 cm, annual) zone of the inland Pacific Northwest region of the United States. Farmers plant deep to reach moisture adequate for germination and emergence. The coleoptile of deep‐planted wheat remains underground. The first leaf protrudes through the tip of the coleoptile and usually emerges about 10 to 12 d after planting. Emergence may be jeopardized by below‐surface buckling of the first leaf. Buckling of the first leaf occurs when its exerted force cannot overcome the density or strength of overlying soil. Small, single‐point load cells were used to measure force exerted by the first leaf of one semidwarf cultivar (‘Norwest 553’) and two standard‐height cultivars (‘Farnum’ and ‘Finley’) as they emerged from a deep planting depth (100 mm) in a small containerized volume of soil. The average maximum before‐buckling emergence force (BBEF) of Norwest 553 and Finley was 12.2 and 11.6 g, respectively. The corresponding value for Farnum (10.9 g) was statistically similar to the BBEF of Finley and less than that of Norwest 553. The measured difference between Farnum and Norwest 553 may be a consequence of variation in coleoptile diameter. Maximum diameter measurements of 1.6 to 1.7 mm were made near the base and in the middle of the Norwest 553 coleoptile. New knowledge generated from this research can be used to make decisions about the focus of future investigations that deal with poorly understood mechanisms responsible for emergence of wheat from deep planting depths.

Agroecological Advantages of Early-Sown Winter Wheat in Semi-Arid Environments: A Comparative Case Study From Southern Australia and Pacific Northwest United States

“…Due to thick soil cover over the seed, it is not the coleoptile that emerges from the soil but rather the first leaf after pushing through the tip of the coleoptile. The first leaf is thin and spindly and, since most often emerging under low soil water potential, lacks much emergence force or lifting capacity (Lutcher et al, 2019). The drier the soil in the seed zone and the deeper the soil cover, the longer it takes seedlings to emerge (Lindstrom et al, 1976).…”

Comparison of Single-Trait and Multi-Trait Genome-Wide Association Models and Inclusion of Correlated Traits in the Dissection of the Genetic Architecture of a Complex Trait in a Breeding Program

“…In Washington state, seedling emergence of deep-sown winter wheat is a complex trait affected by many factors and is dependent on the environment to display variation (Schillinger et al, 1998;Lutcher et al, 2019). Seedling emergence is dependent on deep sowing at depths of 10-15 cm when precipitation is below 150-300 mm annually (Schillinger et al, 1998;Mohan et al, 2013).…”

Comparison of genomic selection models for exploring predictive ability of complex traits in breeding programs

“…Seedling emergence in deep‐sown winter wheat depends on the first true leaf's ability to protrude through the coleoptile and reach the soil surface before a crusting event (Schillinger, 2011). Therefore, emergence is affected by the speed of emergence, force exerted, and lifting capacity of the first leaf (Arndt, 1965; Lutcher et al., 2019; Schillinger et al., 2017). These studies showed that the genetic basis of seedling emergence is a complex trait affected by many factors and is dependent on the environment to display variation (Lutcher et al., 2019; Schillinger et al., 2017).…”

“…Therefore, emergence is affected by the speed of emergence, force exerted, and lifting capacity of the first leaf (Arndt, 1965; Lutcher et al., 2019; Schillinger et al., 2017). These studies showed that the genetic basis of seedling emergence is a complex trait affected by many factors and is dependent on the environment to display variation (Lutcher et al., 2019; Schillinger et al., 2017).…”