Genetic Investigations of Date Palm (Phoenix dactylifera L.) Germplasm Gene Pools from Jigawa, Nigeria

Genetic Investigations of Date Palm (Phoenix dactylifera L.) Germplasm Gene Pools from Jigawa, Nigeria.

Abstract: Date palm cultivation is prevalent in arid and semiarid regions worldwide, including Nigeria, where it holds significant socioeconomic importance in the Sahel, Sudan, and Guinea Savannah ecologies. This study aimed to assess the genetic diversity of date palm crops by conducting surveys and explorations to collect fruit samples from female tree germplasm populations across the gene pools of the Nigerian Institute for Oil Palm Research (NIFOR) at the date palm research substation in Dutse, Jigawa State, Nigeria. A total of 21 accessions were randomly collected from the gene pools, and the collected fruits were analyzed for their proximate and phytochemical compositions. The accessions were evaluated for morphological characteristics using a completely randomized block design (CRBD), with quantitative and qualitative traits measured following standard procedures. Genetic diversity and sex identification were determined using the random amplified polymorphic DNA (RAPD) technique, while cytological analysis was conducted using standard procedures. Proximate composition analysis revealed that accession R13P5 exhibited the highest moisture content of 7.65%. Accession R4P12 had the highest carbohydrate content of 82.32%. Mineral analysis indicated that accession R24P9 had the highest levels of calcium, magnesium, sodium, and potassium, with values of 119.39, 80.55, 13.44, and 423 mg/100 g, respectively. Sugar content analysis showed that accession R5P8 had the highest glucose content (320 mg/g), while R15P6 had the highest fructose and sucrose content (102 and 92 mg/g, respectively). At the late seedling stage, the tallest plant height and largest girth size were observed in accessions R13P5 (39.00 cm) and R5P8 (10.00 cm), respectively. Fruit characteristics analysis revealed that accession R7P1 had the highest fruit weight, fruit diameter, and fruit thickness, with values of 11.85 g, 2.10 mm, and 4.00 mm, respectively. Molecular diversity analysis identified a total of 125 amplified fragments using 6 primers, of which 106 (84.3%) were polymorphic and 19 (15.2%) were monomorphic. Out of the 21 accessions screened for sex determination, 12 were identified as male (R13P1, R4P12, R5P8, R3P22, R1P18, R7P1, R13P5, R13P9, R14P21, R4P29, R16P31, and zariya), and 9 were identified as female (R24P9, R5P20, R2P4, R9P2, R6P20, R9P21, R5P24, R5P6, R1P10). Morphological variations in the male accessions revealed larger girth sizes and a higher number of lower leaf spines, while the female accessions exhibited smaller girth sizes with few to no lower leaf spines. Cytological examination confirmed 2n=36 chromosomes in accessions R5P8 and R16P31, and 2n=28 chromosomes in accession R1P18, with metacentric and submetacentric chromosomes, respectively. The observed high genetic variability among the date palm germplasm in terms of proximate, morphological, and molecular characteristics provides valuable baseline information for the gene pools. The developed qualitative marker for sex determination can be utilized by plant breeders and growers as a time-saving tool for gender identification in date palm seedlings before transplantation in the field.

Genetic Investigations of Date Palm (Phoenix dactylifera L.) Germplasm Gene Pools from Jigawa, Nigeria.

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