Ghulam Sarwar Markhand

Whole genome re-sequencing of date palms yields insights into diversification of a fruit tree crop

Date palms (Phoenix dactylifera) are the most significant perennial crop in arid regions of the Middle East and North Africa. Here, we present a comprehensive catalogue of approximately seven million single nucleotide polymorphisms in date palms based on whole genome re-sequencing of a collection of 62 cultivars. Population structure analysis indicates a major genetic divide between North Africa and the Middle East/South Asian date palms, with evidence of admixture in cultivars from Egypt and Sudan. Genome-wide scans for selection suggest at least 56 genomic regions associated with selective sweeps that may underlie geographic adaptation. We report candidate mutations for trait variation, including nonsense polymorphisms and presence/absence variation in gene content in pathways for key agronomic traits. We also identify a copia-like retrotransposon insertion polymorphism in the R2R3 myb-like orthologue of the oil palm virescens gene associated with fruit colour variation. This analysis documents patterns of post-domestication diversification and provides a genomic resource for this economically important perennial tree crop.

Date Palm Status and Perspective in Pakistan

Date palm (Phoenix dactylifera L.) is the third most important fruit crop after citrus and mango in Pakistan. This crop is found in all four provinces of Pakistan on 90,000 ha with a production of around 600,000 mt yr−1. Pakistan’s position is always among the seven largest producers and exporters of dates in the world. Sindh and Balochistan provinces contribute more than 90 % of production and crop area in Pakistan. In Sindh, Khairpur is the biodiversity center having more than 300 date palm cultivars. Date palm has a very strong effect on socioeconomic activities of the area. The top Pakistani cultivars are Aseel, Dhakki, Begum Jangi, Rabai, and Muzawati. Pakistani date fruit is being exported as fresh, dry, or chohara. Most date-processing factories in Pakistan are located in Khairpur. This chapter provides basic information describing date palm cultivation in Pakistan, major flood-affected date palms and fruit, protection from monsoon rains, the first commercial trial for date palm micropropagation using inflorescence explants at the Date Palm Research Institute (DPRI) at Khairpur, and major date palm problems generally in Pakistan, including diseases and pests, with emphasis on the Khairpur and Balochistan areas, and date fruit drying through the use of solar dryers.