To examine continuous variation of amylose levels in Asian rice (Oryza sativa) landraces, the five putative alleles (Wx a, Wx in, Wx b, Wx op, and wx) at the wx locus were investigated in near-isogenic lines (NILs). Apparent amylose levels ranged from 0.5 to 29.9% in the NILs, showing a positive relation with the levels of Wx gene product, granule-bound starch synthase (GBSS) as well as the enzymatic activity per milligram starch granule. Only opaque (Wx op) accessions had an enzymatic activity per GBSS that was reduced to half the level of the others. Nucleotide sequences in the Wx gene were compared among 18 accessions harboring the five different alleles. Each of the Wx alleles had a unique replacement, frame-shift or splice donor site mutation, suggesting that these nucleotide changes could be reflected in phenotype alterations. A molecular phylogenetic tree constructed using the Wx gene indicated that ssp. japonica forms a distinct clade, whereas ssp. indica forms different clades together with the wild progenitor. Unexpectedly, the wx allele of 160 (indica from Taiwan) joined the japonica lineage; however, comparisons using linked genes for two Taiwanese accessions revealed that the wx gene was the product of gene flow from japonica to indica. Therefore, the japonica lineage frequently included Wx in, Wx b and wx, while Wx a and Wx op were found in the other lineages, strongly suggesting that allelic diversification occurred after divergence of the two subspecies. The present results were discussed in relation to the maintenance of agronomically valuable genes in various landraces.

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thermomechanical processing routes which introduce high densities of dislocations and interfaces into materials. These defect populations introduce long-range stress fields, enabling substantial strengthening of materials. Thus, processing with the aim to introduce high densities of lattice defects into materials is a wellestablished and efficient method to enhance their strength. [12] Yet, when single-phase metallic materials have few defects such as in the recrystallized state and at the beginning of plastic yielding, they often have insufficient intrinsic lattice friction and thus low flow stress. [13,14] The lattice friction, quantified by the Peierls stress, is a measure of the resistance that an infinite straight dislocation has to overcome when moving from one potential valley to the next. The height of this energy barrier scales with the intrinsic atomic-scale lattice distortions and thus differs profoundly in nature from the long-range stress fields imposed by dense defect populations. In other words, the friction stress describes how severely dislocations are dragged as they move through the distorted Peierls potential landscape of massive solid solutions. In that respect, multiprincipal element solid mixtures, often termed high-or medium-entropy alloys (HEAs or MEAs), provide a very promising material design basis because each individual atom experiences a set of different neighbor atoms creating high and ubiquitous local lattice distortions and stresses. [15,16] In that context, multiprincipal element face-centered cubic (fcc) alloys have the potential for achieving an outstanding yield strength-ductility ratio as they naturally carry high inherent lattice distortions. [15,17,18] However, two key challenges have not been addressed in this context so far. First, the yield strength is low due to the close packed fcc lattice structure. [19][20][21] Second, although the friction stress of these alloys is often higher than in pure metals or binary alloys, it is still usually too close to conventional structural alloys. This means that the level of lattice distortion currently exploited in most substitutional solid solution alloys does not contribute significantly to the yield strength. [20,[22][23][24][25][26][27][28] Here, based on a combined theoretical and experimental approach, we show that the degree of lattice distortion is indeed a key parameter in controlling strengthening mechanisms for the design of hitherto unexplored ultrastrong medium-entropy single-phase alloys. For this purpose, we exploit vanadium (V) as a very efficient element in a Severe lattice distortion is a core effect in the design of multiprincipal element alloys with the aim to enhance yield strength, a key indicator in structural engineering. Yet, the yield strength values of medium-and high-entropy alloys investigated so far do not substantially exceed those of conventional alloys owing to the insufficient utilization of lattice distortion. Here it is shown that a simple VCoNi equiatomic medium-entropy alloy exhibits a near 1 GP...

Refractory high entropy alloys feature outstanding properties making them a promising materials class for next-generation hightemperature applications. At high temperatures, materials properties are strongly affected by lattice vibrations (phonons). Phonons critically influence thermal stability, thermodynamic and elastic properties, as well as thermal conductivity. In contrast to perfect crystals and ordered alloys, the inherently present mass and force constant fluctuations in multi-component random alloys (high entropy alloys) can induce significant phonon scattering and broadening. Despite their importance, phonon scattering and broadening have so far only scarcely been investigated for high entropy alloys. We tackle this challenge from a theoretical perspective and employ ab initio calculations to systematically study the impact of force constant and mass fluctuations on the phonon spectral functions of 12 body-centered cubic random alloys, from binaries up to 5-component high entropy alloys, addressing the key question of how chemical complexity impacts phonons. We find that it is crucial to include both mass and force constant fluctuations. If one or the other is neglected, qualitatively wrong results can be obtained such as artificial phonon band gaps. We analyze how the results obtained for the phonons translate into thermodynamically integrated quantities, specifically the vibrational entropy. Changes in the vibrational entropy with increasing the number of elements can be as large as changes in the configurational entropy and are thus important for phase stability considerations. The set of studied alloys includes MoTa, MoTaNb,

Quantitative and well-targeted design of modern alloys is extremely challenging due to their immense compositional space. When considering only 50 elements for compositional blending the number of possible alloys is practically infinite, as is the associated unexplored property realm. In this paper, we present a simple property-targeted quantitative design approach for atomic-level complexity in complex concentrated and high-entropy alloys, based on quantum-mechanically derived atomic-level pressure approximation. It allows identification of the best suited element mix for high solid-solution strengthening using the simple electronegativity difference among the constituent elements. This approach can be used for designing alloys with customized properties, such as a simple binary NiV solid solution whose yield strength exceeds that of the Cantor high-entropy alloy by nearly a factor of two. This study provides general design rules that enable effective utilization of atomic level information to reduce the immense degrees of freedom in compositional space without sacrificing physics-related plausibility.

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