Male Date Palm Research Articles

An evaluation rule to manage productivity properties performance of male date palms

ABSTRACT Male palm trees almost prominently display minute morphological variations; however, date palm growers rely on readily available pollen from unproven male genotypes without giving correct type selection any thought, which may result in low productivity and/or poor fruit quality. This study sought to develop an evaluation rule by calculating an evaluation index for managing the productivity characteristics performance of nine male date palms, which were examined for their pollen productivity, nutritional status and morphological traits from their leaves, pinnae and spathes. The findings showed that the evaluation rule for a male date palm should depend on pollen grains productivity and germination percentage traits with a weight of 5, spathe morphological traits with a weight of 4, pinnae morphological traits with a weight of 3, leaf morphological traits with a weight of 2 and leaf nutritional status with a weight of 1. The best productivity characteristics performance of male date palms was male No. 8 ‘M8’ due to its high evaluation index. The proposed evaluation index criterion will contribute to better information and analytical support for management of the date palm industry to maximise the effectiveness of germplasm conservation and exploitation, as well as procedural and methodological aspects of the analysis.

Modeling the Performance Parameters of Pollen Grains of Male Date Palms Using an Artificial Neural Network Based on the Mineral Composition and Morphological Properties of Their Leaves

One of the key factors for sustainability in agricultural systems, particularly, for cultivation of date palms, is the identification of the performance parameters of the pollen grains of male date palms (Phoenix dactylifera L.). This study was carried out to predict the performance parameters of pollen grains using an artificial neural network (ANN) model. The morphological features of spathe length, spathe weight, number of pinnae per leaf, leaf length, leaf width, length of the pinna part, pinna length, pinna width, length of the spathe stem, and spathe width, as well as the concentrations of minerals such as Mg, N, K, P, and Ca in their leaves were used as inputs to the ANN model. For this purpose, we collected the required data from nine male date palms grown in Saudi Arabia. The ANN model utilized in this work included an input layer with 15 parameters, a hidden layer of 30 neurons, and an output layer with 8 neurons. The ANN model was trained with 27 patterns. Seven patterns were utilized for testing purposes. The coefficient of determination (R2) obtained between the observed and predicted performance parameters’ values using the testing dataset was 0.902 for the number of strands per spathe, 0.967 for strand length, 0.963 for the number of flowers per strand, 0.941 for the number of flowers per spathe, 0.985 for the weight of pollen grains per spathe, 0.810 for the pollen grains’ viability, 0.936 for the pollen grains’ length, and 0.992 for the pollen grains’ width. The length of the spathe stem had the most critical effect on how the ANN model predicted the values of the dependent variables, i.e., the number of strands per spathe, with a percentage of contribution of 17.66%; the weight of pollen grains per spathe, with 17.85%; the pollen grains’ length, with 19.78%, and the pollen grains’ width, with a percentage of contribution of 30.59%. Spathe weight had the most critical influence on strand length and pollen grains’ viability, with percentages of 26.29% and 14.92%, respectively. Leaf width had the most critical effect on the number of flowers per spathe, with a percentage of 12.55%. The elemental concentration of K in the male date palm leaves had the most critical effect on the number of flowers per strand, with a percentage of 13.98%. It was therefore concluded that using a modeling process with the ANN technique can help estimate the performance parameters of male date palms’ pollen grains for different purposes, such as providing a starting point for mathematical analyses associated with the physiological mechanisms of male date palm. Moreover, the outcomes of this research work can be supportive as a practical tool in this field of study.

Molecular Identification of Genetic Diversity and Population Structure in Moroccan Male Date Palm (Phoenix dactylifera L.) Using Inter-Simple Sequence Repeat, Direct Amplification of Minisatellite DNA, and Simple Sequence Repeat Markers

Understanding genetic diversity and population structure plays a vital role in the efficient use of available material in plant-breeding programs and in germplasm conservation strategies. In the present study, we aim to evaluate the genetic variations and population structure of male date palms from Morocco. The genetic diversity of 100 date palm (Phoenix dactylifera L.) genotypes was investigated using the performance of three types of molecular markers: inter-simple sequence repeats (ISSRs), direct amplification of minisatellite DNA (DAMD), and simple sequence repeats (SSRs). On the basis of their polymorphic information content (PIC) (ISSRs = 0.38; DAMD = 0.4; SSRs = 0.33), effective multiplex ratio (EMR) (ISSRs = 27.34; DAMD = 52.31; SSRs = 22.20), Resolving power Rp (ISSR = 13.81; DAMD = 28.73; SSR = 14.6), and marker index (MI) (ISSRs = 9.22; DAMD = 20.23; SSRs = 7.54) values, all markers used in our study are considered informative markers. Among them, DAMD markers demonstrated slightly higher informativeness compared to ISSR and SSR markers. A total of 216, 438, and 248 bands were, respectively, detected using ISSRs, DAMD, and SSRs, with 95%, 98% and 94% of polymorphism, respectively. The AMOVA results revealed considerable diversity within date palms. The PCOa results showed that males of Tinghir and Errachidia were regrouped into the same cluster, while males of Goulmima were separated into another group. A cluster and structure analysis separated the studied genotypes into three groups. One group comprises genotypes of males from Zagora with some female varieties scattered in this group. The second group includes male genotypes from Goulmima along with accessions of female and male varieties. The third group contains males of Errachidia, Tata and Tinghir populations. The cluster and structure analysis separated the studied genotypes according to their origin.

Study on the effects of pollen sources on the agronomic, biochemical, mineral, and pomological traits of date palm (Phoenix dactylifera L.) cv 'Deglet Nour' fruits in Degache Oases (Tunisia)

AbstractGiven the dioecious nature of date palms, selecting an effective pollinizer bearing a substantial quantity of high-quality pollen is imperative. In this study, we investigated the effects of 11 male date palm cultivars from Tunisia on the production of female trees, fruit sets, and the characteristics of 'Deglet Nour' cultivar dates. The comparison of pollen germination rates showed that ABD1 and P169 pollens exhibited outstanding viability, with 98.7% and 98.3%, respectively. On the other hand, P169 pollen had the highest germination rate, at 86.3%. The most remarkable fruit set (90.7%) and retention rate (69.7%) were observed in response to P13 pollen. In response to the P165 pollinator, the fruit stood out among the resulting fruits for their notable weight, averaging 11.6 g. In addition, pollination with P90 increased total soluble solids (measured at 74.4°Brix in the Tamr stage), whereas P7-pollinated fruits recorded the highest levels of reducing sugars, reaching 41%. Notably, the highest acidity levels were found in P7-pollinated fruits (0.29%), and pollen sources significantly influenced the fruits' mineral content.Moreover, regarding pomological characteristics, fruits pollinated with P4 attained maximum size, measuring 4.10 cm. Conversely, P7-pollinated fruits had a notable width of 2.02 cm. These findings illustrate the possibility of the selective application of high-value pollinizers and emphasize the direct influence of pollen sources on fruit quantity and quality.

Analyzing Phytohormone Levels in Fruits of Date Palm Phoenix dactylifera L. Derived from Tissue Culture under Different Pollination Treatments

This study evaluated three male date palm varieties, namely, Red-Ganami, Red-Ganami + Khakri Al-Adi and Red-Ganami + Al-Canary, in three age of spathes (early, late and middle) in a private orchard at Al-Seebah district, Basrah province. The plants were subjected to two pollination dates immediately after opening of female flowers and three days after opening of female flowers. The contents of auxin-like substances, gibberellin and abscisic acid in the flowers were determined. The second pollination date resulted in the highest contents of auxins, gibberellins and abscisic acid, with values of 24.305, 138.660 and 12.355 µg.gm-1, respectively. The mixture of Red-Ganami + canary cultivars had the highest concentrations of auxin 24.512 µg.gm -1 and gibberellins 136.842 µg.gm-1, whereas Red-Ganami had the highest concentration of abscisic acid 3.554 μg.gm-1. Early age of spathes showed significant differences in the concentrations of auxin and abscisic acid, with average values of 26.015 and 14.031 µg.gm-1, respectively. Late postmenopausal age recorded the highest concentration of gibberellins at 136.842 μg.gm-1. For the two- and three-way interactions, a statistically significant superiority was observed in most of the study coefficients. In conclusion, the contents of auxins, gibberellins and abscisic acid significantly differed with the pollination date and the pollin cultivar combinations showed the highest concentrations of these substances. The different ages of male puberty also affected pollination and fertilization

Content of fixed and volatile oils of pollen grains of five male cultivar of date palm Phoenix dactylifera L.

This study was conducted on the pollen of five male date palm cultivars to determine their content of fixed and volatile oils. Male cultivars were selected: Ghanamy Akhder, Ghanamy Ahmar, khukri, Wardi and Smesmi. Mature pollens were taken before their covers were cracked and the pollen extraction process was performed. The volatile oils were extracted using the Clevenger device, and the fixed oils were extracted using the Sexolate device. The results of the study showed that the male variety of , Ghanamy Ahmar was significantly superior to the rest of the varieties in the content of fixed oils, while the male variety of Wardi recorded the lowest rate, and the varieties of Ghanamy Akhder, khukri, and Smesmi did not differ in their content of fixed oils. As for volatile oils, the results of the study showed that the male variety, Ghanami Akhdar, was significantly superior to the rest of the male varieties, and recorded the highest rate . While the male variety, Wardi, recorded the lowest rate of pollen content of essential oils, The other male varieties did not differ among themselves in terms of the essential oil content of their pollen grains. The results of the study also showed the difference between the male varieties in terms of the qualitative characteristics of the oils in terms of density and refractive index.

Heteromorphism of normal and abnormal flowers of date palm cv. “Barhee” and comparison of green and red Ghanami pollens as dominant pollen

A major limitation to the use of tissue culture techniques for propagating date palms cv. "Barhee" is the production of plants with abnormal phenotypes (low fruit set and multi-carple fruits) as a result of somaclonal diversity. In addition, pollination with specific of male date palm pollen results in better fruit set and thus higher fruit production. So, this study was conducted to compare the anatomical and morphological characteristics, investigate the possible abnormalities of off-shoot and tissue culture-derived trees, and compare the pollen grain characteristics of Green Ghanami and Red Ghanami male date palm cultivars as the dominant Pollinator of "Barhee" during the growing season of 2019–2020 at Date palm and Tropical Research Center and Shahid Chamran Univeristy of Ahvaz, Iran. This experiment was laid out as a randomized complete blocks design with nine replications. The results revealed that the pollen grain of Green Ghanami had higher polar and equatorial axis than those of Red Ghanami, while the P/E ratio index and inter-edge distance of pollen grains of Red Ghanami were significantly higher than those of Green Ghanami. On the other hand, off-shoot-derived trees of cv. "Barhee" had larger flowers with lower flower density per strand than the tissue culture-derived trees. The stigma characteristics of the upper and lower flowers strands of the offshoot-derived trees were similar to each other and had three completely intact stigmas capable of receiving pollen grains. In tissue culture-derived trees, the lower flowers of the strand had wrinkled and dried stigmas, whereas the three stigmas of the upper flowers were completely undamaged. In addition, the flower of the tissue culture-derived trees had three carpels, one of which had an ovary with an aborted egg. In contrast, in the flower of off shoot-derived trees, only one carpel had a healthy ovary and the other two carpels were without ovaries and degenerated.Generally, it can be concluded that heteromorphic self-incompatibility and abnormality of the atypical flower stigma of tissue culture-derived trees cause the pollen grain not to germinate and grow inside the style.

Male diversity matters: genetic structuring of insular male date palm (Phoenix dactylifera L.) revealed valuable breeding and conservation resources

ABSTRACT Most male date palms available for pollinating different female cultivars have mainly originated from seed propagation resulting in many different local males that represent a source of genetic diversity. Favourable fruit production is related to the quality of pollen and its compatibility with a certain female variety. Therefore, the genetic characterisation of the male progenitors should be the first step to establish a selection programme to produce superior males through different procedures. In this study, the genetic diversity and population structure of 72 male date palm accessions were investigated using 15 microsatellite loci. The highest mean number of alleles per locus was obtained for Tozeur group. Bayesian model-based clustering analysis indicated the presence of two differentiated endemic male date palm genetic clusters, continental and insular, with the presence of introduced accessions originating from the Middle East. The diversity analysis in the insular region of Tunisia, which had never been performed before, revealed that this germplasm enclosed valuable endemic resources supporting the hypothesis of the presence of wild material. These findings are crucial for identifying interesting genotypes that can be integrated into international coordinated actions of Phoenix dactylifera L. breeding programmes and the protection and conservation of valuable resources.

Agro-morphological traits assessment of Tunisian male date palms (Phœnix dactylifera L.) for preservation and sustainable utilization of local germplasm

Date palm (Phœnix dactylifera L.) like other crop species in the arid Mediterranean region is being threatened by genetic erosion and climate change. Therefore, the understanding and assessment of the diversity extent of this species is a primary requisite for preserving these crop resources. This study was designed to quantify the potential of Tunisian male date palms using a set of agro-morphological characteristics i.e. flowering traits, inflorescence morphology and pollen quality. The flowering time traits exhibited a trend of precocious phenotype at emergence spathe trait and the dominance of the full-season phenotype at the opening date. At inflorescence morphology, all observed traits expressed wide ranges which reflected the broad variability of the evaluated male genotypes. Significant difference was recorded for the majority of the examined traits with a high significant variation in the tree quantitative traits: Spathe Total Length, Spathe Maximum Width and Length to the brunched part. Pollen viability ranged from 51.10% to 98.75% while the germination rate was between 0.90% and 70.50%. Our phenotypic investigation has allowed the identification of males with desirable agronomic traits which have been genotyped using 18 nuclear SSR markers and a chloroplast minisatellite for preservation and effective utilization purposes.

The Genetic Diversity Analysis of Tunisian Male Date Palm Cultivars (Phoneix dactylifera L.) Revealed by Phenotypic and Molecular Markers

Tunisian oases reveal an important genetic heritage of date palm cultivars, with various qualities of use. Since the beginning of the century, this heritage has evolved to a selective orientation based on the monoculture of "Deglet Nour," this orientation risks causing the loss of many cultivars. The male of the date palm is part of this heritage and so far remains marginalized. Although they are important for the date palm production cycle, it is in this context that lies our work to study the genetic diversity of a collection of male date palm pollinators from southern Tunisia. The morphological study of the 20 date palm pollinators using 45 IPGRI (International Plant Genetic Resources Institute) descriptors showed significant discrimination, with a similarity index ranging from 0.207 to 0.457, divided them into five similarity groups. The use of 7 ISSR (Inter Simple Sequences Repeat) primers resulted in 64 reproducible bands, of which 57 were 90% polymorphic, and statistical analysis showed a more or less significant genetic diversity with genetic distances 0.491 to 0.873. According to the Mentel test, a non-significant weak correlation (r = 0.015) was noted between the molecular and morphological data. However, the processing of molecular data by various methods generated very significant correlations. Indeed, the correlation between the SM (Simple matching) coefficient and the DICE coefficient showed an important correlation with r = 0.748, which confirms the discriminating power of the ISSR markers in studying the genetic diversity of date palm pollinators.

Evaluation of Pollen Production of Common Male Date Palms Grown in the Mexicali Valley, Mexico

The aim of this study was the evaluation of date palm (Phoenix dactylifera L.) pollen production during the 2021 and 2022 seasons in the Mexicali Valley, Mexico. Twelve seed-propagated male palms of 20 years of age and similar vigor were selected and grouped into four groups with phenotypic characteristics of the common female cultivars in the area (Medjool, Deglet Noor, Khadrawy, and Zahidi). The pollen was extracted manually, with average production among all individuals of 780.94 and 777.11 g, in 26 and 24 inflorescences, respectively, for each year. Likewise, the flowering period on average was 47 and 41 days for each year. The pollen extracted from the earliest four inflorescences averaged 38.7 and 32.55 g, while that of the latest one produced 10.70 g and 18.28 g for each year, respectively. Seedling male palms with a phenotype similar to the Deglet Noor cultivar produced the greatest amount of pollen with 1250.98 and 1114.26 g on average for each year, produced during a late, short flowering period. Likewise, those palms with phenotypes similar to the Medjool cultivar produced the second-highest amount of pollen with 851.28 and 866.43 g on average for each year, produced during an early, long flowering period. Finally, an in vivo viability test through the fruit set percentage, revealed that the use of any of these four pollen sources would be suitable for the pollination of the recipient female cultivar Medjool, the most widely cultivated variety in Mexico. These results will allow date producers to select and propagate better pollen-producing male palms.

Gas Chromatography-Mass Spectrometry Based Metabolite Profiling and In Silico Activity Prediction of Phytoconstituents in Phoenix dactylifera L. Leaves Extracts of Kachchh Region

Phoenix dactylifera L. commonly known as date palm is one of the major flora grown in the Kachchh region. Date palm is dioecious plant, that is, it owns separate male and female trees. Gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography, high-performance thin layer chromatography, and infrared red spectroscopy are some widely utilized sophisticated analytical techniques for the identification of bioactive phytoconstituents in medicinal plants. The present study aims to identify phytoconstituents present in ethyl acetate extract of male and female date palm leaves using GC-MS. These identified bioactive phytoconstituents were subjected toin silico useful biological activity prediction using pass online server. The study concluded that both male and female extracts were enriched phytochemicals possessing diverse valuable biological activity such as antihypercholestrolemic, anticancer, antineopolastic, lipid metabolism regulator, hepatoprotectant, and apoptosis antagonist.

The effect of nanoparticles of in vitro propagation of seedling male date palm by immature inflorescences

The effect of nanoparticles of in vitro propagation of seedling male date palm by immature inflorescences

Effect of flowering stage and storage conditions on pollen quality of six male date palm genotypes

Availability of efficient male genotypes is critical for successful artificial pollination and regular bearing of female date palms. The effect of flowering stage and storage conditions on pollen quality of six male date palm genotypes encoded ‘ABD1′, ‘P4′, ‘P3′, ‘P8′, ‘P7′ and ‘P13′were evaluated. Pollen collected from spathes developed at the middle of flowering stage exhibited the best viability (90%) and germinability (85%) compared to other stages. Pollen viability was greater than 90%, except for ‘P8′ that exhibited 80%, while, germinability greatly varied among the genotypes. Pollen quality decreased during 4 months of storage upon genotype and temperature, with a minimum reduction at −30 °C followed by 4 °C. Heat shock exposure (33 ± 2 °C) following storage revealed that pollen stored at −30 °C or 4 °C should be used for pollination on the same day of take out to avoid dramatic quality loss. The ‘ABD1′, an early flowering genotype, proved highest pollen quality both at fresh stage and after storage. While, the ‘P3′, a late flowering genotype, retained its pollen quality during storage. However, the ‘P13′ genotype exhibited excellent pollen quality when fresh, but greatly loses germinability during storage.

Effect of some male date palms on yield and fruit quality of Barhee cultivar

Effect of some male date palms on yield and fruit quality of Barhee cultivar

Single tube amplification and detection of male date palm using polymerase chain reaction and loop-mediated isothermal amplification technique

Single tube amplification and detection of male date palm using polymerase chain reaction and loop-mediated isothermal amplification technique

Effect of sonication pretreatment on physicochemical, surface, thermal, and functional properties of fibro‐proteic extracts from male date palm flowers

This study aims to investigate the effect of the application of an ultrasound pretreatment on physicochemical, surface, thermal, and functional properties of two extracts from male date palm flowers. The obtained extracts were compared based on their structural and functional properties. It was proved that the application of sonication pretreatment has modified significantly (p < .05) the extract's characteristics. The protein yield, the essential amino acid content and the protein solubility were improved (29.61%, 29.22 g/100 g protein, and 91.1% for native sample against 35.26%, 41.04 g/100 g protein, and 100% for treated sample, respectively), while the protein content and the surfactant behavior at 1% were decreased due to the liberation of other compounds than protein. Moreover, the sonication has engendered some structural modifications such as the dissociation of some intermolecular bonds (FTIR) and the increase of crystalline region (X-ray), which influenced the protein unfolding and have led to the decrease of enthalpy (DSC) (272.2 against 228.6 J/g) and the decrease of water-holding capacity (11.62 against 9.51 g water/g of dry sample). Practical applications The male date palm flowers (MDPF) present a rich matrix composed mainly of dietary fiber, protein, and minerals. The protein fraction of MDPF was considered as an excellent source of amino acids supplying the human requirements. The dietary fiber fraction was composed essentially of insoluble dietary fibers which contribute to a balanced diet by creating satiety feeling and facilitating the intestinal transit. The fibro-proteic extract (FPE) of MDPF could be a potential functional ingredient for food applications. The physicochemical and functional properties of the FPE was changed by ultrasound pretreatment, which was beneficial to improve the protein yield, the amino acid profile, and the protein solubility. Nevertheless, both treated and non-treated samples showed promising nutritional and functional characteristics that could be used in the food industry to ameliorate food quality.

Effect of succinylation on the secondary structures, surface, and thermal properties of date palm pollen protein concentrate.

The present study was attempted to investigate the effect of succinylation, as chemical modification, on the functionality of male date palm pollen protein concentrate (MDPPPC). Succinylation was applied at two levels, 4 and 8mol of succinic acid per mole of lysine. 4M and 8M were compared to the native MDPPPC. Findings proved that succinylation improved the surface properties of pollen protein including solubility and surfactant activity. Increased solubility of succinylated MDPPPC has been noticed especially in pH superior to pHi. The results from the differential scanning calorimetry showed a significant decrease (P < 0.05) of the denaturation temperature and the heat enthalpy for succinylated MDPPPC. β turn of succinylated MDPPPC increased significantly (P < 0.05) at the expense of β sheet indicating that the protein gained more mobility after succinylation which explains the enhancement of the functional properties and promotes the use of succinylated protein as a techno-functional ingredient.

Effect of extraction methods on the physicochemical, structural, functional, and antioxidant properties of the dietary fiber concentrates from male date palm flowers.

The current study evaluates the effect of both aqueous and alkaline extraction methods on the physicochemical, structural, functional, and antioxidant properties of dietary fibers (DF) from male date palm flowers (MDPF). The DF extracted by the alkali treatment (ADF) display a higher DF content as well as lower protein and lipid content than the DF resulting from watery extraction (WDF). The scanning electron microscopy, the Fourier-transform infrared spectroscopy, and the X-ray diffraction show that the alkaline treatment contributes to a slight modification of the structural characteristics of ADF leading to better purity and functional properties. The oil holding capacity and the antioxidant activity of ADF have improved compared to the WDF, which makes this concentrate a promoting functional ingredient and a natural antioxidant. Therefore, these findings confirm the wealth of both concentrates in DF, especially ADF, as well as their potential of functional and antioxidant properties, which emphasize their suitability to be used in food applications as functional ingredients. PRACTICAL APPLICATIONS: Nowadays, studies on the extraction of DF from vegetable waste are of considerable interest in the face of the rising global demand for dietetic food. The male date palm flowers (MDPF), an agricultural waste generated during the period of pollination, are valuable natural sources of DF and antioxidants. The insoluble DF of MDPF could be essential in a balanced diet as they could fight against obesity by creating a feeling of satiety. The presence of antioxidants, which are known for preventing or slowing cell damage caused by free radicals, could contribute to the improvement of the antioxidant properties of the formulated food. The functional properties of DF concentrates from MDPF are able to solve the technical problems of agri-food industries when used as food ingredients. The use of DF from MDPF, consequently, contributes to the minimization of waste and provides value addition to the by-product considered as waste in agricultural processing.

Male date palm flowers: Valuable nutritional food ingredients and alternative antioxidant source and antimicrobial agent

The aim of this study was to assess the nutritional properties of male date palm flower (MDPF) via determining its mineral, amino acid and bioactive compounds profiles and to investigate its antioxidant and antibacterial activities in order to prove its possible use as a healthy and potential natural source in human dietary diets. Results showed that MDPF is an excellent source of minerals especially regarding its high potassium and phosphorus contents (2684.23 and 318.66 mg/100 g, respectively). Moreover, the amino acids profile of MDPF showed considerable amounts supplying the human requirements. The phytochemical compounds analysis showed high content of polyphenol and flavonoids (3829.22 mg EAG/100 g and 168.31 mg EQ/100 g, respectively) promoting high antioxidant activity. The quantitative and qualitative analysis (LC-ESI-MS) of phenolic acids and flavonoids led to the identification of 18 phenolic compounds that were dominated by quinic acid (84.52%). The MDPF extract showed a potential antioxidant activity determined by different tests, namely DPPH radicals scavenging activity, ferric reducing power assay, ferrous ion chelating capacity and β-carotene bleaching assay. The MDPF also exhibited significant antibacterial activity against some tested bacteria. In conclusion, owing to its nutritional profile and biological activities, MDPF could be considered as potential functional-ingredient for food applications.