Towards Sex Determination of Date Palm

DOI: 10.1007/978-94-007-1318-5_26 In book: Date Palm Biotechnology, pp.551-566


In the date palm (Phoenix dactylifera), a dioecious mode and late initial reproductive age of 5–10 years are major practical constraints to genetic improvement.
Improvement of the existing palm cultivars or selection of new ones with superior characters is a tedious endeavor due to
the long life cycle of the date palm tree and its heterozygous nature. Sexual propagation method cannot be used commercially
for propagating the cultivars of interest in a true-to-type manner. Currently there is no reliable method to identify sex
at the early seedling stage. Early sex identification of young seedlings could enhance breeding programs and generate experimental
male and female genetic stocks that will help the genetic improvement of the date palm. Moreover, the selection and identification
of superior seedling characters for yield enhancement and to improve the physical and chemical properties of fruits is of
great commercial interest. There has been significant progress in our understanding of sex-determining mechanisms in date
palm using traditional means. But physiological and cytological methods do not give obvious differences between male and female
date palms. Biotechnology, as a new tool in date palm breeding, can be useful to improve the qualities of palm trees through
early sex identification. Although molecular markers have been introduced in date palm programs, few research efforts have
been geared toward studying the early sex determination in the plant. This chapter will focus on genetic and molecular basis
of sex determination in date palm in attempting to develop reliable methods to identify sex at an early stage of seedlings.

KeywordsBiotechnology-Breeding-Sex determination-Molecular markers

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    • "It is more practicable to make a selection in the nursery of healthy females, along with a few healthy males, to establish a seedling-date plantation. Current molecular studies (Aberlenc-Bertossi, et al., 2010; Ageez and Madboly, 2011; Bekheet and Hanafy, 2011; Cherif et al., 2012; Elmeer and Mattat, 2012; Moghaieb et al., 2010; Younis et al., 2008) are expected to provide the means to identify the gender of seedlings at an early stage and thereby simplify propagation and breeding. Early selection of young seedlings could enhance date palm breeding programs and generate experimental male and female genetic stocks (Siljak-Yakovlev et al., 1996). "
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    ABSTRACT: An accelerating worldwide trend toward planting elite cultivars is leading to genetic erosion and a narrowing of the gene pool upon which the date-palm industry is based. Large numbers of seedling dates are known in many major date-growing countries, as well as in naturalized populations in Spain and the Americas where the palm was intentionally introduced. Seedling dates growing under different climatic conditions from those of the major production areas represent potential genetic resources that should be evaluated for desirable traits. Utilizing modern biotechnology, traits such as disease and pest resistance, hardiness, tolerance of salty soils and improved fruit quality and quantity potentially can be transferred to elite cultivars to sustain and further improve fruit production. Specific examples of important seedling date palm populations in Spain, Peru and Mexico are discussed, as well as new cultivars derived from seedlings in the United States. Research on seedling date populations is recommended, along with the establishment of ex situ germplasm collections of promising specimens as living plants, cold storage of seeds or cryopreservation.
    Full-text · Article · Apr 2013 · Emirates Journal of Food and Agriculture
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    ABSTRACT: Date palm (Phoenix dactylifera) is one of the oldest cultivated trees and is critical to the development of arid land. The date palm is a dioecious monocot with separate male and female trees. This presents a challenge in development as it is impossible to distinguish trees until they flower approximately five to eight years after planting. We have developed PCR-based assays capable of sex differentiation in multiple date palm cultivars. The primers are designed across gender-specific polymorphisms and demonstrated greater than 90% accuracy in distinguishing date palm gender across multiple varieties. These results indicate that the primers should be helpful in rapidly distinguishing date palm gender from the earliest stages that DNA can safely be collected. This is a vast savings in time over present approaches.
    Full-text · Article · Dec 2011 · American Journal of Botany
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    ABSTRACT: To establish a proteomic reference map of date palm leaves (Deglet Nour cultivar), we separated and identified leaf proteins using two-dimensional polyacrylamide gel electrophoresis and mass spectrometry, respectively. In total, 284 spots were excised from gel and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Among them, 158 were successfully identified (i.e, a success rate of 55.6%) conducting to the identification of 126 unique proteins. These proteins were then clustered according to their functional annotations. Identified proteins were involved in metabolism, electron transport, photosynthesis, protein synthesis, cell structure or defence. However, 29.4 % of the identifications gave unknown function. We then compared the proteome map of female and male trees. Only one discriminated spot was found to be specific of the gender. We identified the corresponding protein as an ABC superfamily ATP binding cassette transporter, ABC protein, a protein whose an ortholog in Arabidopsis thaliana was already reported as required for male fertility and pollen formation. The relevance of this protein as gender biomarker was then confirmed in four other cultivars, i.e., Aligue, Khouet Aligue, Kentichi and Kenta. Such biomarker should be helpful in rapidly distinguishing date palm gender of immature trees.
    Full-text · Article · Jan 2013 · Plant Omics
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