Plant growth promoting rhizobacteria Ochrobactrum lupini KUDC1013 and Novosphingobium pentaromativorans KUDC1065 isolated from Dokdo Island, S. Korea are capable of eliciting induced systemic resistance (ISR) in pepper against bacterial spot disease. The present study aimed to determine whether plant growth-promoting rhizobacteria (PGPR) strains including strain KUDC1013, strain KUDC1065, and Paenibacillus polymyxa E681 either singly or in combinations were evaluated to have the capacity for potential biological control and plant growth promotion effect in the field trials. Under greenhouse conditions, the induced systemic resistance (ISR) effect of treatment with strains KUDC1013 and KUDC1065 differed according to pepper growth stages. Drenching of 3-week-old pepper seedlings with the KUDC-1013 strain significantly reduced the disease symptoms. In contrast, treatment with the KUDC1065 strain significantly protected 5-week-old pepper seedlings. Under field conditions, peppers treated with PGPR mixtures containing E681 and KUDC1013, either in a two-way combination, were showed greater effect on plant growth than those treated with an individual treatment. Collectively, the application of mixtures of PGPR strains on pepper might be considered as a potential biological control under greenhouse and field conditions.

Genome-wide association study (GWAS) is effective in identifying favorable alleles for traits of interest with high mapping resolution in crop species. In this study, we conducted GWAS to explore quantitative trait loci (QTL) for eight fruit traits using 162 tomato accessions with diverse genetic backgrounds. The eight traits included fruit weight, fruit width, fruit height, fruit shape index, pericarp thickness, locule number, fruit firmness, and brix. Phenotypic variations of these traits in the tomato collection were evaluated with three replicates in field trials over three years. We filtered 34,550 confident SNPs from the 51 K Axiom® tomato array based on < 10% of missing data and > 5% of minor allele frequency for association analysis. The 162 tomato accessions were divided into seven clusters and their membership coefficients were used to account for population structure along with a kinship matrix. To identify marker-trait associations (MTAs), four phenotypic data sets representing each of three years and combined were independently analyzed in the multilocus mixed model (MLMM). A total of 30 significant MTAs was detected over data sets for eight fruit traits at P < 0.0005. The number of MTA per trait ranged from one (brix) to seven (fruit weight and fruit width). Two SNP markers on chromosomes 1 and 2 were significantly associated with multiple traits, suggesting pleiotropic effects of QTL. Furthermore, 16 of 30 MTAs suggest potential novel QTL for eight fruit traits. These results facilitate genetic dissection of tomato fruit traits and provide a useful resource to develop molecular tools for improving fruit traits via marker-assisted selection and genomic selection in tomato breeding programs.

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KC00256, KC00406, KC00462, KC00463, KC00820, and KC00821, the genetic resources that have previously been reported as moderately resistant to Phytophthora capsici, as well as the line KC01322, a new source of moderate resistance introduced from Laos, were tested against two strains (Pc003 and Pc005) of P. capsici. We also determined the nuclear restorer genotypes of these lines, in regards to their interaction with cytoplasmic male sterility, through crossing the resources with cytoplasmic male sterile Punggok-A (Srfrf) and determining the fertility of the F 1 hybrids. The studied lines exhibited a low level of resistance to both the strains of P. capsici compared to highly resistant CM334, but their response was fairly consistent for both P. capsici strains. KC00406, KC00462, KC00463, and KC01322 produced stable, male fertile F 1 plants indicating that they are restorers with genotype N(S)RfRf. KC00821 produced male sterile F 1 plants and was identified as a maintainer with genotype Nrfrf. The F 1 plants of the KC00820 cross, however, set a few male fertile flowers in the greenhouse at seedling stage, then became male sterile after being transplanted to the plastic greenhouse soil in May and remained so to the end of the growing season. Therefore, KC00820 is an unstable maintainer with genotype Nrfrf. The moderate resistance exhibited by these genetic resources may be integrated into breeding programs aimed at promoting higher levels resistance via recurrent selection or hybridization.

The objective of this study was to elucidate the effect of light-emitting diode treatment on early growth and inorganic elements in leaf lettuce (Lactuca sativa L. 'Oak Leaf'). In changes to leaf morphology, shoot elongation and hypocotyl length showed poor growth under red light irradiation, while red+blue light irradiation induced shorter plant height and more leaves, resulting in increased fresh weight. With respect to Hunter's color and SPAD values, lettuce seedlings grown under red+ blue and fluorescent light irradiation had a higher a* value but showed no other changes to SPAD values. Interestingly, redness in relative chlorophyll content was 1.4 times higher under red+blue light irradiation. Inorganic element (N, Ca, Mg, and Fe) and ascorbic acid concentrations increased in lettuce plants grown under LED light irradiation compared to those of lettuce grown under fluorescent light, which showed a higher P content. In conclusion, red+blue light irradiation, which stimulates growth and higher nutrient uptake in leaf lettuce, could be employed in containers equipped with LEDs.