Pepper plants experience complex environmental factors including abiotic and biotic stresses in field and the importance of climate changes including low and high temperatures has been emerged. Low temperature stress in the growth and development is one of the most critical issues, which directly impact on the crop yield and productivity of pepper plants. It is essential to select and breed low temperature-(LT) tolerant pepper (Capsicum annuum L.) cultivars. The research was performed to assess the agronomical traits of 39 pepper accessions belonging to chili and bell fruit types which cultivated two different night temperature set-points at 15°C for suboptimal temperature (CT) and at 10°C for low temperature (LT), respectively. Plant heights (PH) of most pepper accessions in LT were significantly decreased compared to those in CT. The stem diameter (SD) and the length of main axis (LMA) were various depending on the genotypes under LT. Moreover, the number of flowers (NFL), the total number of fruits (NFR), fruit yield (FY), fruit fresh weight (FFW), fruit length (FL), fruit diameter (FD), and the number of seeds in a fruit (NSF) were notably declined in LT compared to CT. The evaluated agronomical traits between LT and CT were further applied for the correlation analysis, the principal component analysis (PCA), and the hierarchical cluster analysis. Notably, FY trait was correlated with other reproductive traits including NFR, FFW, FD, and FL on positive directions and LT treated-39 pepper accessions were clustered into seven groups by the clustering analysis. The selected accessions were primarily involved with the positive trends with the reproductive index including NFR, FL, FD, and FW traits and would be used for pepper breeding programs on developing LT-tolerant cultivars.

Tomato is exposure to diverse abiotic stresses. Cold stress is one of harsh environmental stresses and abnormal low temperature affects tomato growth and development including physio- logical disorders, flower drops, and abnormal fruit morphology, causing the decrease of tomato yield and a fruit quality. It is important to identify low temperature-(LT) tolerant tomato (Solanum lycopersicum L.) cultivars relying on different fruit types. This study focused on analyzing physiological traits of 35 tomato accessions with three different fruit types (cherry, medium, and large sizes) under night temperature set-points of 15°C for normal temperature (NT) and 10°C for LT, respectively. Plant heights (PH) of most tomato accessions in LT were remarkably decreased compared to those in NT. The growth of leaf length (LL) and leaf width (LW) was reduced depending on the genotypes under LT. In addition, the number of fruits (NFR), fruit set (FS), fruit yield (FY), and marketable yield (MY) were negatively affected in LT. The variation was further investigated by the correlation analysis, the principal component (PCA), and the cluster analysis. Interestingly, positive correlations between different vegetative and reproductive traits were uncovered. Multivariate analysis including the PCA and hierarchical clustering classified LT-treated 35 tomato accessions into four major groups. The identified accessions were associated with vegetative and reproductive parameters on positive directions and might be utilized for breeding programs on selecting LT-tolerant cultivars.