Are awns truly relevant for wheat yields? A study of performance of awned/awnless isogenic lines and their response to source–sink manipulations

Weight of individual wheat grains estimated from high-throughput digital images of grain area

“…Among a longer list of examples, it was necessary to determine not only AGW but also the individual weight of particular grains for a mechanistic explanation of (i) a negative relationship between AGW and GN in response to yielding condition (e.g. Acreche and Slafer, 2006), (ii) the effects of awns on potential grain size (Sanchez-Bragado et al, 2020), (iii) the relevance of pericarp characteristics in determining grain size (Hasan et al, 2011;Brinton et al, 2017;Herrera and Calderini, 2020), and (iv) the genetic and molecular basis of trade-offs between AGW and spike fertility (Zhai et al, 2018). Indeed, it seems more frequent than not that treatments modifying GN bring about concomitant changes in AGW (Frederick and Bauer, 1999), regardless of whether the effects are due to genetic or environmental factors (Slafer et al, 2015b, and references quoted therein).…”

“…The most frequently used equipment of this type for the determination of wheat grain dimensions is likely the Marvin seed analyser (e.g. Gegas et al, 2010;Neuweiler et al, 2020;Sanchez-Bragado et al, 2020). Taking advantage that grains of modern cultivars do not vary appreciably in shape (Gegas et al, 2010), a single equation might be generated to transform the dimensions taken from 2-D images of individual grains into their dry weights that could be reasonably valid across genotypes and growing conditions.…”

Unveiling the Actual Functions of Awns in Grasses: From Yield Potential to Quality Traits

“…Grain yield in grass species is the product of grain yield components, molecular genetic factors, and growing conditions and their interaction [ 30 ]. For the most part, grain yield is decided by grain number and grain weight [ 31 ], with increased grain weight being linked with assimilate availability and distribution [ 32 , 33 ].…”

“…However, Li et al [ 16 ] concluded that the impact of awns on grain yield was uncertain, especially for short-awned species, since the grass inflorescence comprises other photosynthetically active organs, such as palea, lemma, glumes, and seed pericarp. Besides, in some species, the contribution of awns during grain filling could be compensated or possibly exceeded by assimilates used during awn development [ 30 , 50 ]. Based on these results, we hypothesize the phenotypic role of awns varies with the species, environment, and awn length ( Table 1 ).…”

Improving Grain Yield via Promotion of Kernel Weight in High Yielding Winter Wheat Genotypes

“…Wheat yield-related traits are all complex agronomic and physiological traits [ 47 ], integration of traits such as the source–sink balance must be considered to achieve successful grain yield gain [ 48 , 49 ]. Sink size in developing yield organs is determined by the number of spikes per unit area, grains per spike, sink size per grain, and thousand-grain weight.…”