Construction of an Evaluation System and Comprehensive Assessment of the Suitability of Different Processing Peppers for Mechanized Transplanting and Harvesting

To address the current mismatch between processing pepper cultivars and the requirements of mechanized production, this study aims to construct a comprehensive evaluation model for the suitability of mechanized transplanting and harvesting, thereby screening highly adaptable varieties. An evaluation system comprising eight indicators for the transplanting stage and thirteen indicators for the harvesting stage was established using 105 processing pepper varieties (including 56 erect-fruit and 49 pendent-fruit peppers). Variation analysis, hierarchical clustering, principal component analysis (PCA), and Pearson correlation analysis were integrated to reveal the clustering effects of the cultivars and the synergistic and antagonistic relationships among the indicators. Furthermore, a combined CRITIC–VIKOR model was applied to conduct a multi-criteria comprehensive ranking of mechanization suitability. The results indicated that the biomechanical properties of processing peppers exhibited a significantly higher degree of variation than conventional morphological indicators (e.g., the coefficient of variation for lodging resistance reached 93.60%). Significant differences were observed in the mechanization adaptation mechanisms between the two pepper types: erect-fruit peppers were primarily limited by fruiting branch toughness (weight: 5.907%), whereas pendent-fruit peppers were mainly constrained by fruit morphological uniformity. Compared with the traditional PCA model, the CRITIC–VIKOR model effectively identified varieties with critical biomechanical defects by constraining the “individual regret value”, which highly aligns with Liebig’s Law of the Minimum in mechanized operations. Based on this model, varieties with superior comprehensive mechanization adaptability were successfully identified, notably C21, C55, and C23 (erect-fruit peppers), and D20, D11, and D19 (pendent-fruit peppers). This study provides a theoretical foundation and mathematical modeling support for the directional breeding of mechanization-suitable cultivars, the integration of agronomy and agricultural machinery, and the quantitative evaluation of multi-trait pyramiding in processing peppers.