Genome-wide association study and development of molecular markers for yield and quality traits in peanut (Arachis hypogaea L.).

BACKGROUND: This study aims to decipher the genetic basis governing yield components and quality attributes of peanuts, a critical aspect for advancing molecular breeding techniques. Integrating genotype re-sequencing and phenotypic evaluations of seven yield components and two grain quality traits across four distinct environments allowed for the execution of a genome-wide association study (GWAS). RESULTS: The nine phenotypic traits were all continuous and followed a normal distribution. The broad heritability ranged from 88.09 to 98.08%, and the genotype-environment interaction effects were all significant. There was a highly significant negative correlation between protein content (PC) and oil content (OC). The 10× genome re-sequencing of 199 peanut accessions yielded a total of 631,988 high-quality single nucleotide polymorphisms (SNPs), with 374 significant SNP loci identified in association with the nine traits of interest. Notably, 66 of these pertinent SNPs were detected in multiple environments, and 48 of them were linked to multiple traits of interest. Five loci situated on chromosome 16 (Chr16) exhibited pleiotropic effects on yield traits, accounting for 17.64-32.61% of the observed phenotypic variation. Two loci on Chr08 were found to be strongly associated with protein and oil contents, accounting for 12.86% and 14.06% of their respective phenotypic variations, respectively. Linkage disequilibrium (LD) block analysis of these seven loci unraveled five nonsynonymous variants, leading to the identification of one yield-related candidate gene and two quality-related candidate genes. The correlation between phenotypic variation and SNP loci in these candidate genes was validated by Kompetitive allele-specific PCR (KASP) marker analysis. CONCLUSIONS: Overall, molecular markers were developed for genetic loci associated with yield and quality traits through a GWAS investigation of 199 peanut accessions across four distinct environments. These molecular tools can aid in the development of desirable peanut germplasm with an equilibrium of yield and quality through marker-assisted breeding.

Acceptor-free photomultiplication-type organic photodetectors.

A series of organic photodetectors (OPDs) is prepared with two donor materials as active layers, with the only difference being the weight ratio of the two donors (one polymer and one small molecule). The OPDs work according to a photodiode model with an external quantum efficiency (EQE) of less than 10% at -10 V when the weight ratio of the two materials is 1 : 1 (wt/wt). The EQE of an OPD with P3HT:DRCN5T (100 : 2, wt/wt) as the active layer reaches 1400% at -10 V, exhibiting the photomultiplication (PM) phenomenon. The EQE values of PM-type OPDs can be markedly improved along with a bias increase, and the champion EQE reaches 10 600% at -20 V. The small number of small molecules can be used as electron traps due to the different lowest unoccupied molecular orbital (LUMO) levels of the two donors, and photogenerated electrons can be trapped in the small molecules surrounded by P3HT. The trapped electrons near the Al electrode can induce interfacial band bending for efficient hole tunneling injection from an external circuit. This work provides a new strategy for realizing acceptor-free PM-type OPDs, which may inspire us to further develop organic electronic devices with single type organic semiconducting materials.

One key issue in characterization of organic solar cells with solution processed interfacial layers.

Solution processed interfacial layers are commonly employed in bulk heterojunction organic solar cells (OSCs) for better charge collection. PDIN interfacial layers were prepared by employing a static or dynamic spin coating method from PDIN methanol solution, and defined as the S-PDIN or D-PDIN layer. The OSCs with a S-PDIN layer exhibit 13.88% power conversion efficiency (PCE) with a virtual high short circuit density (JSC) of 26.45 mA cm-2 and relatively low fill factor (FF) of 58.94% during the current density versus voltage (J-V) measurement without a shadow mask. 12.56% PCE is achieved for OSCs with a D-PDIN layer, along with a JSC of 18.85 mA cm-2 and FF of 74.88%. Over 77% FFs are obtained for OSCs with a S-PDIN or D-PDIN layer during J-V measurement with a shadow mask, and both OSCs exhibit a very similar JSC and PCE. The virtual high JSCs and relatively low FF of OSCs with a S-PDIN layer may be due to the enhanced conductivity of PEDOT:PSS during preparation of the PDIN layer by the SSC method, which can be further confirmed from the OSCs with a methanol treated PEDOT:PSS layer. This work indicates that a well-balanced JSC and FF should be an important evaluating indicator for efficient OSCs, and an appropriate shadow mask is necessary to measure the J-V curves of OSCs with a solution processed interfacial layer.

Photomultiplication type narrowband organic photodetectors working at forward and reverse bias.

It is a great challenge to obtain narrowband and photomultiplication (PM) type organic photodetectors (OPDs) without optical filters due to the broad absorption range and large exciton binding energy of organic materials. Narrowband OPDs with the special structure of ITO/PFN-OX/P3HT : PC61BM (100 : 1,wt/wt)/Al were successfully fabricated with different active layer thicknesses, exhibiting a tunable response window and PM phenomenon under bi-directional bias. The OPDs exhibit U-shaped EQE spectra with two narrowband response windows under forward bias and a single narrowband response window under reverse bias. The best EQE of the optimized OPDs with a 4.0 µm thick active layer approaches 7160% or 8180% for 340 nm or 650 nm light illumination at 60 V and 1640% for 665 nm light illumination at -60 V, respectively. The most important features of the optimized OPDs is that the full width at half-maximum (FWHM) of their response windows is less than 30 nm under bi-directional biases, which can be well maintained at large bias. The PM type narrowband OPDs working at bi-directional bias are the first to be reported with a tunable response range, further indicating that the density of the electrons trapped in PC61BM near the hole injection electrode plays the key role in determining the interfacial band bending for hole tunneling injection from the external circuit.