Morphological Marker for Gender Identification in Date Palm (Phoenix dactylifera L.) at the Seedling Stage Using RAPD-PCR Analysis

Abstract

Date palm (Phoenix dactylifera L.) is an important fruit crop in arid and semi-arid regions in Nigeria. At the seedling stage, male and female trees cannot be clearly distinguished until about four years after planting when the palms first flower. This research was aimed to differentiate gender at seedling stage among date palm accessions obtained from NIFOR in Nigeria using morphological marker and a specially developed DNA RAPD marker technique. A PCR based method was found to be successful using extracts from young leaves. The male determinant marker was able to distinguish a male-specific fragment at 200bp while male and female individuals were identified on a fragment of 400 bp. The male determinant marker generated fragments that consisted of one banding patterns in male DNA extracts and no banding pattern in female. When the 21 date palm seedlings were screened, 12 were identified as male and 9 as being female. Morphologically, the male seedlings were observed to have a larger girth size and a higher number of lower leaf spines while the female seedlings were observed to possess a smaller or thinner girth size with little number of lower leaf spines. The primers was repeated for other cultivars and the same DNA banding patterns and morphological differences were observed. The developed sex determinant marker could be used for gender identification at the seedling stage of date palms. Plant breeders and growers may adopt this marker as a tool for gender identification in date palm seedlings before planting in the field.