Morpho-physiological and biochemical diversity assessment of low-chill peach genotypes for germplasm conservation

Peach ( Prunus persica L. Batsch) is an important temperate fruit grown globally for its nutritional value. There is a worldwide interest in assessing low-chilling germplasm that is well-adapted to warm regions. Exploiting diversity is essential to conserve existing germplasm and evaluate elite genotypes for breeding. The northern areas of Pakistan are rich in various local peach accessions but are rarely explored. Therefore, there is a need to characterize these accessions based on morphological and biochemical traits to improve local cultivars with better nutrition and adaptation to climate change. A field experiment was conducted during 2024-25 to evaluate the morphological and biochemical characteristics of 22 peach accessions collected from various areas of Punjab and Khyber Pakhtunkhwa, Pakistan. The data was subjected to the multivariate analysis technique of principal component analysis. The results revealed substantial morphological and biochemical variations among the evaluated peach accessions collected from diverse agroecological regions of Pakistan, with genetic and environmental effects potentially contributing to the observed variation. There was a huge diversity among the selected peach genotypes for fruit length (29.7–63.8 mm), fruit width (40.3–58.2 mm), seed length (17.3–36.1 mm), seed width (15.3–35.4 mm), fruit weight (33–162 g), and seed weight (3–9 g). In addition, these genotypes contained high nutritional values a range of total soluble solids (5.2–13.3 ºBrix), vitamin C (98.0–182.2 mg/100 g), total sugars (39.4–74.6%), non-reducing sugars (22.5–64.4%) and reducing sugars (10.9–26.6%), total phenolic content (185.51–406.67 mg 100 g − 1 ) and total flavonoid content (87.4–149.7 mg g − 1 ). Principal component analysis (PCA) explained 84.7% of the total variation in the first six principal components, with PC1 (23.9%) mainly associated with seed weight, fruit length, fruit weight, seed length, and pH, while PC2 (18.7%) was primarily influenced by fruit weight, fruit width, total sugars, and non-reducing sugars, indicating these traits as the major contributors to genotype discrimination. Among qualitative traits, the highest coefficient of variation (CV) was observed for anthocyanin coloration of flesh (87.3%), fruit over color (75.2%), and flesh type (60.3%). Based on agro-morphological and biochemical assessments, the dendrogram generated through agglomerative hierarchical clustering (AHC) categorized peach into three main clusters, with six accessions in cluster one, five in cluster two, and 11 in cluster three. The accessions ‘CTRU’, ‘TIA’, ‘PCH’, and ‘SWT1’ exhibited superior fruit weight, total soluble solids and phenolic content, antioxidant activity, and vitamin C content, respectively, indicating their potential as promising germplasm for future peach improvement; however, their genetic potential should be validated under common garden or multi-environment trials to distinguish genetic effects from environmental influences before their use in breeding programs.