Genetic diversity and population structure analysis of mango (Mangifera indica L.) germplasm using microsatellite markers.

Abstract

Background: Mango (Mangifera indica L.), known as the "king of fruits," is a major tropical fruit belonging to the Anacardiaceae family. Cultivated for over 4,000 years, it is native to southern Asia, eastern India, and Burma. The mango family includes 73 genera and 850 species, mostly found in tropical regions. In Pakistan, mango is the second most cultivated fruit after citrus, primarily grown in Punjab and Sindh. Key varieties include Sindhri and Chaunsa, with 7-10% of the crop exported annually, generating about $20 million.

Results: This study aims to assess the genetic diversity of Pakistan's mango germplasm using simple sequence repeat (SSR) markers for effective crop breeding. Mango germplasm samples were collected from Multan Mango Research Institute. Both local and exotic varieties were included. Genomic DNA was extracted from mango leaves using a Plant Genomic DNA Kit, and its quality was assessed via spectrophotometry. The study aimed to evaluate genetic relatedness among 38 mango cultivars of Pakistan and other countries using SSR primers. Twelve labeled primers were tested for their amplification efficiency through PCR, using labeled forward and unlabeled reverse primers. This study on mango germplasm from Pakistan, using SSR markers, revealed significant genetic diversity among 38 native and exotic cultivars. All primer sets produced clear bands, confirming well-optimized PCR conditions. SSR analysis showed high allelic variation, useful for improving traits like disease resistance, fruit quality, and yield. Principal Coordinate Analysis (PCoA) and cluster analysis indicated both separation and overlap between local and exotic varieties, with some clustering based on geographic origin. Most genetic variation was found within cultivars, highlighting a strong genetic base in Pakistani mango germplasm.

Conclusions: The study confirmed close genetic links between Pakistani mangoes and those from the Philippines, Indonesia, and Thailand, offering valuable insight for future breeding programs. This study demonstrated the potential of molecular marker techniques to enhance mango breeding by selecting high-yield, disease-resistant, and climate-tolerant varieties. Emphasizing the importance of genetic diversity, it addressed future challenges like climate change and disease outbreaks. Based on the findings, a strategic plan was proposed to strengthen germplasm collection and develop climate-smart mango varieties suited for modern production systems. Overall, the research offers valuable insights into mango genetics and presents an effective approach to boost mango production in Pakistan and globally.