Table_4_Pod Morphology, Primary and Secondary Metabolite Profiles in Non-grafted and Grafted Carob Germplasm Are Configured by Agro-Environmental Zone, Genotype, and Growing Season.DOCX

Carob is a predominantly rainfed tree crop of high nutritive value and a long history of adaptation to the edaphoclimatic stress conditions of the Mediterranean. However, declining attention to the carob tree in recent decades has aggravated genetic erosion. The extant in situ germplasm varies both in terms of pod morphology and composition, reflecting the genetic and physiological divide chiefly among grafted and non-grafted material, and possibly the impact of variable agro-environments. Accordingly, the present study aimed to establish a systematic categorization of the genetic and phenotypic diversity encountered across carob germplasm identified in situ throughout Cyprus, a historical center of production and genetic diversity for the species. Linking pod morphology, primary and secondary metabolite profiles with genotyped source material originating in different agro-environments and crop seasons would provide a framework for interpreting (a) the interaction of these factors in configuring carob pod physicochemical constitution, and (b) the relative stability of phenotypic traits against environmental and seasonal variation. Microsatellite analysis discriminated 36 genotypes out of the 124 trees located in nine traditional agro-environmental zones and revealed low genetic diversity within the grafted germplasm. Two landraces were identified: “Tillyria,” which is widespread and predominant, and “Kountourka,” which is mainly localized to the northeastern peninsula of Karpasia. Morphological traits, such as seeds-to-pod weight ratio, pod width and thickness were principally under genetic control. Contrarily, compositional traits, particularly total phenolic content—including condensed tannins, in vitro antioxidant capacity and to a lesser extent gallic acid, organic acids and minerals were under agro-environmental control. Agro-environmental zone also modulated principally fructose and glucose; sucrose was modulated equally by genotype and agro-environment, while total sugars were under genetic control. Statistically significant differences between seasons were detected for all traits except for the seeds-to-pod weight ratio, pod length and width. Hierarchical cluster analysis corroborates that Cyprus may be divided into two major agro-environmental zones modulating the compositional properties of the carob pulp. The present study provides a comprehensive insight into the extant carob genetic resources of Cyprus and advances our understanding of how genetic, agro-environmental and seasonal factors interact in shaping carob pod morphology and composition.

角豆树（carob）是一类主要依靠自然降水的木本经济作物，不仅营养价值极高，且长期适应地中海区域的土壤-气候复合胁迫环境，拥有悠久的适应历史。然而近数十年来，学界对该物种的关注度持续下降，加剧了其遗传侵蚀。现存的原位种质资源在荚果形态与组分上均存在显著差异，这主要反映了嫁接与非嫁接材料间的遗传与生理分化，同时也可能受不同农业生态环境的影响。据此，本研究旨在对全塞浦路斯境内原位发现的角豆树种质资源所蕴含的遗传与表型多样性进行系统分类——塞浦路斯是该物种的传统生产中心与遗传多样性热点区域。将荚果形态、初生与次生代谢物谱与源自不同农业生态环境及种植季的基因型鉴定材料相结合，可为解析以下两方面内容提供研究框架：其一，上述因素共同作用塑造角豆荚果理化组成的机制；其二，表型性状对环境与季节变化的相对稳定性。微卫星（microsatellite）分析从9个传统农业生态区的124株植株中区分出36个基因型，并揭示了嫁接种质资源内较低的遗传多样性。研究共鉴定出两个地方品种：分布广泛且占主导地位的“蒂利亚（Tillyria）”，以及主要分布于卡帕西亚半岛东北部的“孔图尔卡（Kountourka）”。荚果种子重量占比、荚果宽度与厚度等形态性状主要受遗传因素调控。与之相反，组分性状——尤其是总酚含量（包括缩合单宁）、体外抗氧化能力，以及在较小程度上的没食子酸、有机酸与矿物质含量——主要受农业生态环境调控。农业生态区同样主要影响果糖与葡萄糖的含量；蔗糖含量同时受基因型与农业生态环境的同等调控，而总糖含量则受遗传因素主导。除种子-荚果重量比、荚果长度与宽度外，其余所有性状在不同种植季间均存在统计学意义上的显著差异。层次聚类分析证实，塞浦路斯可划分为两个主要农业生态区，二者可调控角豆果肉的组分特性。本研究全面解析了塞浦路斯现存的角豆树遗传资源，并深化了我们对遗传、农业生态环境与季节因素共同作用塑造角豆荚果形态与组分机制的认知。