Multivariate analysis of garlic (Allium sativum L.) germplasm in response to cold tolerance regimes

Low temperature is a major environmental constraint that limits crop productivity. In this investigation, 256 diverse garlic germplasm were tested for their cold tolerance at the seedling stage by being exposed to natural low-temperature stress −10∼-15 ​°C for the lowest at night for eight days. Several plant development indicators, as well as the cold index (CI), were studied. The findings showed a significant range of CI among these accessions, ranging from 16.98 to 70.38. All germplasms were divided into five groups according to their CI and different grades of tolerance to low-temperature stress. Four highly tolerant and eight low temperature-tolerant germplasm were screened out. Multivariate analysis of the acquired phenomic data using principal component analysis (PCA) addressed sufficient variability, i.e., 70.5% revealed a significant influence of low-temperature stress on growth and bulb attributes. PCA and cluster analysis classified accessions into three groups representing high diversity, providing feasibility for their use in breeding programs. In many phenotypic variables, different germplasm responded differently to low-temperature stress. Furthermore, an exceptionally significantly negative correlation was observed between CI and agronomic traits (PH, LL, LW, RHL) and initiation of bulb traits (Bulb height, width, weight). This study provides a sustainable solution and useful resources for the garlic low temperature tolerant genetic enhancement.