PCR-based SNP Markers for Sex Identification in Date Palm (Phoenix dactylifera L.) cv. KL1

The date palm (Phoenix dactylifera L.) is a valuable commercial plant in the Arecaceae family. It is a sweet, edible fruit containing a lot of nutrients including carbs, sugar, protein, and potassium. Maejo 36 or KL1 is a Thai date palm with excellent fresh fruit quality that is mostly grown in Thailand's northern and northeastern areas. The main issue with date palm farming is that there is no reliable way to discriminate between male and female seedlings prior to flowering, which takes 3 - 5 years after planting. An increase in the number of female date palm plants in commercial orchards may increase in date production and profitable investment. The present research aims to develop Single Nucleotide Polymorphisms (SNP) markers for the sex identification of date palm cv. KL1. The SNP markers were designed by analysis of nucleotide sequence difference from GenBank (accession number GL746268.1). The results revealed that SNP primers; PH02F - PdaNu01 (PdaNU02 or PdaNU03) - PdaNU05 used in multiplex PCR technique can precisely distinguish the sex of date palm by generating 2 different sizes of PCR-products in male plants, and only 1 size of PCR-product in female plants. This research indicates that SNP markers with multiplex-PCR technique are a high potential method for identifying the sex of date palm cv. KL1 may be used to increase female plants for cultivation at the seedling stage, which is highly beneficial for commercial date palm production.HIGHLIGHTSDate palm is currently an economic fruits crops in ThailandThe sex of date palm can be identified by phenotype in flowering stage until five years after plantingThe amplicon patterns in male and female date palm generated by SNP marker are applicable to predict their genders at an early seedling stageThe use of SNP marker is highly beneficial for commercial date palm productionGRAPHICAL ABSTRACT