Ampelographic Characterization of the A’asmi Cultivar of Yemeni Grape (Vitis vinifera L.)

The study was conducted to characterize the morphological traits of A’asmi Cultivar of Yemeni grape (Vitis vinifera L.) in the Bani Hashish district during the 2021 and 2022 seasons, based on OIV, UPOV, and IPGRI standards. The aim was to establish a database documenting the morphological characteristics and certain chemical properties of the Cultivar, to support breeding programs, preserve genetic diversity, and enhance agricultural productivity amid environmental challenges. The study involved 10 fruiting vines from a farm in the village of Bayt al-Nukhif, Wadi al-Sir, where 105 traits were measured, encompassing young and mature shoots, leaves, flowers, clusters, berries, and seeds, in addition to the evaluation of selected chemical properties such as soluble sugars, acidity, pH, and vitamin C using standardized methodologies. The results revealed a notable coherence in the morphological traits of the Cultivar. The young shoot was characterized by an open and fully developed apex before the node, indicating vigorous vegetative growth and an ability to adapt to warm seasons, while a weak expression of anthocyanins on the pubescence suggested a potential genetic limitation in expressing this pigment and its effect on the plant’s response to environmental stresses. The mature shoot exhibited a nearly vertical growth pattern with a balanced color distribution on its sides and a reduced pubescence density, which may improve ventilation and reduce the risk of fungal diseases. The leaves maintained stability in terms of shape, size, and number of lobes, with a balanced pigment distribution that reflects an equilibrium between genetic and environmental factors to enhance photosynthetic efficiency and nutrient transport. At the cluster and berry level, productive traits were manifested through a loose distribution of berries and a long conical shape, along with an increase in berry number and stability in dimensional ratios and weight. The seeds showed dimensional stability with variations in biomass accumulation, reflecting the influence of environmental factors. Furthermore, the hermaphroditic floral structure contributed to both self- and cross-pollination, thereby enhancing genetic diversity. Overall, the study comprehensively documented and evaluated the morphological and chemical performance of the A’asmi Cultivar under changing environmental conditions.