Pomology
Tavakil Rasteh; Javad Erfani moghadam; Seyyed Samih Marashi
Abstract
IntroductionThe date palm (Phoenix dactylifera L.) belongs to the family Arecaceae is a dioecious trees. Due to the problems of non-overlapping flowering of some male and female palm trees, commercial date production requires artificial pollination. Temperature is an important environmental factor influencing ...
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IntroductionThe date palm (Phoenix dactylifera L.) belongs to the family Arecaceae is a dioecious trees. Due to the problems of non-overlapping flowering of some male and female palm trees, commercial date production requires artificial pollination. Temperature is an important environmental factor influencing the pollination, fertilization and fruit set of the date palm. Availability of efficient male pollinators are of great importance in date palm production chain and for regular yearly bearing as the quantity and quality of pollen is a yield determining factor. The flowering and pollination period of date palm varies upon cultivar, geographic location and climatic conditions. However, frequent asynchronous flowering of date palm male and female trees occur due to climatic changes and abiotic stress. In such cases, farmers may pollinate their trees with pollen of a known male conserved at ambient conditions from the previous season; however, this is mostly result in a low fruit set and yield.Materials and MethodsIn this study, a factorial test was performed based on a completely random design with three replications at the laboratory of the Horticulture department at Ilam University to determine the rate of germination in five male date palm cultivars. The first factor consisted of nine temperature levels of 15, 18, 21, 24, 27, 30, 33, 36 and 39 and the second factor referred to the cultivar of the pollinator which had five levels of ‘Ghanami Sorkh’, ‘Ghanami Sabz’, ‘Sabz Parak’, ‘Nare Pakutah’ and ‘Khareji’. The pollen of the above-mentioned cultivars was obtained from the date palm Germplasm collection at the Date Palm and Iranian Tropical Fruits Institute in the city of Ahwaz. In the early days of the flowering season (March), the cultivars under study were identified and labeled. They were then checked on a daily basis and whenever the sheaths were ripe enough, they were picked and preserved in a sterile environment in room temperature. After the sheaths opened, the flower clusters were dried in the same environment and at the same temperature. Then, the cluster strings were separated and kept in a freezer at -18 °C until it was time for the test. Viability and vitality of the pollen was specified through the dying method using Acetocarmine solution.Results and DiscussionThe results showed that there was a significant difference among cultivars, temperature and interactions of them at the level of 1%. Among the studied temperatures, the highest germination of pollen grains in all cultivars occurred at 30 °C, followed by 33 °C and 27 °C, respectively, and the lowest germination percentage were obtained at 15 °C. Among cultivars, the percentage of pollen germination in ‘Ghanami Sorkh’ was quite high (92.45%), and ‘Nare Pakutah’ (87.33%), also, simultaneously ‘Sabz Parak’ (84.82%) and in the ‘Khareji’ cultivar was the lowest. However, the percentage of pollen germination in ‘Ghanami Sorkh’ cultivar was higher than 59% under a wide range of temperature from 21 to 39 °C. Furthermore, the percentage of Pollen germination was reduced rapidly at temperatures less than 21 Cº and reach 15.85% in 15 °C. The germination percentage of pollen grains in ‘Nare Pakutah’ cultivar in the temperature range of 21 to 39 degrees Celsius was higher than 57%. The germination percentage of pollen grains in ‘Sabz Parak’ cultivar decreased with less acceleration than ‘Ghanami Sorkh’ at lower and upper temperatures of 30 °C, so that at 36 and 39 °C had the highest amount of germination compared to the other cultivars. Also, the germination rate of pollens in ‘Ghanami Sorkh’ cultivar were investigated above 57% in the wide temperature range from 21 to 39 °C.ConclusionAccording to the findings of this study, the timing of pollination plays a crucial role in the fertility of male date palm cultivars, with the optimal temperature being around 30°C. It is essential to select cultivars that exhibit a high rate of pollen germination and contribute positively to fruit properties. Male cultivars such as 'Ghanami Sorkh', 'Sabz Parak', and 'Nare Pakutah' demonstrated a broader range of optimum temperatures for pollen germination. Therefore, these cultivars are recommended for climates characterized by significant temperature fluctuations during the flowering period of female date palms.
Abbas Joulani; Yavar Sharafi; Javad Sabbaghpour Heris
Abstract
Introduction: Sour cherry (Prunus cerasuc L.) is one of the most important stone fruit of Rosaceae family which have a high nutritional value. Based on FAO statistics, Iran was ranked the 3rd to 6th among the main sour cherry producer countries in the world. Most of the sour cherry cultivars are self-compatible, ...
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Introduction: Sour cherry (Prunus cerasuc L.) is one of the most important stone fruit of Rosaceae family which have a high nutritional value. Based on FAO statistics, Iran was ranked the 3rd to 6th among the main sour cherry producer countries in the world. Most of the sour cherry cultivars are self-compatible, but self-incompatible cultivars have been reported currently. Allotetraploidy of sour cherry complicates the self-incompatibility segregation in the progeny, so this studies have been less accomplished in Iran. The sour cherry is an allotetraploid species which possibly stand up as a result of usual hybridization between the dwarf cherry P. fruticosa and sweet cherry P. avium. Similar to other species of the Prunus, the phenomenon of gametophytic self-incompatibility (GSI) happens in sour cherry. It prevents self-fertilization and facilitate fertilization with pollen of other genotypes within same species. Self-incompatibility consists of arresting pollen-tube growth in the pistil if the pollen tube contains the same S-allele that is present in the pistil. The phenomenon of self-incompatibility in plants of Rosaceae family is controlled by two genes at the S-locus. The specificity of the pistil is encoded by a gene responsible for the synthesis of the ribonuclease protein (S-RNase), whereas the specificity of the pollen is controlled by the gene encoding an F-box protein (S-haplotype-specific F-box protein – SFB) 3a). The tightly linked genetic unit of the pistil S-allele (SRNase) and pollen S-allele is called S-haplotype. Materials and Methods: In the present study, pollen-pistil compatibility relationships among some sour cherry cultivars and selected genotypes were investigated by controlled pollination and pollen tube penetration by fluorescence microscopy. Cultivars were include ‘Meteor’, ‘Mont Morency’, ‘Majarestani’ and ‘Mahalli’ so, genotype1 were selected. After controlled pollination fruit setting was studied and the pollen tubes growth along the style was studied using fluorescent microscope. Crosses were selected based on synchronized flowering time among cultivars and genotypes and included ‘Mont Morency’ × ‘Meteor’, ‘Meteor’ × ‘Mahalli’, ‘Meteor’ × ‘Majarestani’, ‘Meteor’ × ‘Genotype 1’, ‘Mont Morency’ × ‘Mahalli’, ‘Mont Morency’ × ‘Majarestani’, ‘Mont Morency’ × ‘Genotype 1’, ‘Mahalli’ × ‘Majarestani’, ‘Mahalli’ × ‘Genotype 1’ and ‘Majarestani’ × ‘Genotype 1’, respectively. For each cross, 2 branches were randomly selected in female cultivars in winter. On each branch, including 30 floral buds at ‘balloon stage’ were tagged and bagged to prevent the entrance of any foreign pollen. On the day of anthesis, ready-to-dehisce anthers were collected from male cultivar, maintained on a moist filter paper in petri plates at 4 ºC in refrigerator till they dehisce. Pollens from these anthers were used as a source of male gametes later. Once stigma turned receptive, cross-pollination treatments were carried out in the field as designed scheme for 12 successive days. After every 24 hrs. up to 120 hrs. post-pollination, 12 pistils per treatment were fixed in FAA (formaldehyde/glacial acetic acid/70% alcohol in the ratio of 1:1:18) for 24 hrs. Followed by washings with water to remove traces of alcohol, if any, and cleared in 5% KOH at 60 ºC for fluorescence microscopy. Staining regime, as described in Sabbaghpour et al. (2020) the number of pollen tubes in the upper and mid-parts of the style and in the ovary was employed to enable visualization of the pollen germination on the stigma. Percentage of pollen germination was determined as the proportion of pollen grains that germinated on the stigma to the total number present on a scale of 100. Pollen tube number at three levels was calculated as an average of 5 (n=10). For an easy understanding of growth pattern of pollen tubes inside the style and ovary, the stylar portion, which measures 1.8 ± 0.07 cm on an average, was divided into two parts: the middle and the base. A single, longitudinal incision was then carefully given on one portion of the style using a fine needle and made wide open. Pollen tubes inside the style were critically observed under fluorescence microscope at 100x magnification. Number of them was carefully recorded and data generated for different experimental sets. Results and Discussion: Results showed that maximum pollen tube number penetrated to the ovary and final fruit set were observed in cross ‘Mahalli’בMajarestani’. Also, minimum pollen tube in the ovary and final fruit set were observed in ‘Meteor’בMahalli’ and ‘Meteor’בGenotype 1’ crosses. Conclusion: Based on the obtained results cross-incompatibility was not observed among the studied cultivars and genotypes. Therefore, they could be planted in the sour cherry breeding programs and orchards establishment based on their blooming time.
