A genome-wide association study of early-maturation traits in upland cotton based on the CottonSNP8oK array

Genome-wide association studies （GWASs） efficiently identify genetic loci controlling traits at a relatively high resolution. In this study, variations in major early-maturation traits, including seedling period （SP）, bud period （BP）, flower and boll period （FBP）, and growth period （GP）, of 169 upland cotton accessions were investigated, and a GWAS of early maturation was performed based on a CottonSNPSoK array. A total of 49,650 high-quality single-nucleotide polymorphisms （SNPs） were screened, and 29 significant SNPs located on chromosomes A6, A7, A8, D% D2, and D9, were repeatedly identified as associated with early-maturation traits, in at least two environments or two algorithms. Of these 29 significant SNPs, I, 12, 11, and 5 were related to SP, BP, FBP, and GP, respectively. Six peak SNPs, TM47967,TM13732, TM2o937, TM28428, TM5o283, and TM72552, exhibited phenotypic contributions of approximately lo%, which could allow them to be used for marker-assisted selection. One of these, TM72552, as well as four other SNPs, TM72554, TM72555, TM72558, and TM72559, corresponded to the quantitative trait loci previously reported. In total, 274 candidate genes were identified from the genome sequences of upland cotton and were categorized based on their functional annotations. Finally, our studies identified Gh_DoIGo34o and Gh_DoIGo34~ as potential candidate genes for improving cotton early maturity.

Structure evolution,dielectric,and conductivity behavior of(K_(0.5)Na_(0.5))NbO_(3)-Bi(Zn_(2/3)Nb_(1/3))O_(3) ceramics

(1-x)K_(0.5)Na_(0.5)Nb0_(3-x)Bi(Zn_(2/3)Nb_(1/3))0_(3)((1-x)KNN-xBZN,x=0.010,0.015,0.020,0.025,and 0.030)lead-free ceramics were fabricated via a traditional solid-state method.The crystal structure,microstructure,dielectric,and conductivity behavior of this system were studied.Combined with X-ray diffraction(XRD)patterns,Rietveld refinement,and dielectric spectroscopy,an orthorhombic phase was determined for x=0.010,an orthorhombic-tetragonal mixed phase was identified for x=0.015,and a rhombohedral symmetry appears in 0.020≤x≤0.030.Both 0.98KNN-0.02BZN and 0.975KNN-0.025BZN ceramics exhibit stable permittivity and low dielectric loss tangent(tan)in wide temperature ranges owing to the combination of rhombohedral-tetragonal step-like feature and the diffuse phase transition from tetragonal to cubic.The activation energies of dielectric relaxation and conductivity behavior at high temperatures initially decrease slightly,then drop sharply,and finally decline slowly,which could be attributed to microstructure morphologies and the concentration of oxygen vacancies.