**1. Introduction**

The impact of climate change on agriculture varies depending on the region [1]. The environmental effects on plants can emerge as reduced water availability, rising temperatures, the pest and disease epidemics and an increase in the frequency of different extreme events [2]. Alternative varieties/types or new crops are required to provide a steady food supply under changing environmental conditions [3]. Most of agricultural systems in different countries, therefore, have re-designed their breeding approaches based on growing population and climate change. Increasing research focused on developing and improving plants that are underutilized or neglected should be one of the important parts of new breeding studies. *Lathyrus sativus* L. is a legume crop that belongs to the Lathyrus genus, which includes 187 different species and subspecies [4,5]. Grass pea is recognized as one of the most resilient and versatile crops, thriving in extreme environments and climatic conditions such as cold, heat, drought, salinity-affected soils, and flooding, and is resistant to insect attacks, when compared to other legume crops [4,6]. These characteristics make it a superior product for guaranteeing food security, particularly in the face of anticipated climate challenges [3]. Its seeds contain about 8.6–34.6% protein content, which is higher than chickpea [7], and can replace rapeseed and soybean meal in animal feed, moderately [8]. It is therefore used, not only for human food, but also for livestock feed, forage and green manure [9]. According to Hanbury et al. [10], the grass pea offers a cheap, high-protein, and currently under-utilized feed source due to the rising demand for animal products.

**Citation:** Arslan, M.; Yol, E.; Türk, M. Disentangling the Genetic Diversity of Grass Pea Germplasm Grown under Lowland and Highland Conditions. *Agronomy* **2022**, *12*, 2426. https://doi.org/10.3390/ agronomy12102426

Academic Editors: Channapatna S. Prakash, Ali Raza, Xiling Zou and Daojie Wang

Received: 23 September 2022 Accepted: 4 October 2022 Published: 6 October 2022

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**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

However, excessive consumption of grass pea seeds can cause lathyrism, occurred by the non-protein amino acid β-N-oxalyl-L-α, β-diaminopropionic acid (β-ODAP). It is thought that the presence of β-ODAP as a free amino acid in seeds and in significant concentrations in drought-tolerant grass pea is what causes this debilitating illness [11] affecting both animals and humans [12]. Indeed, when consumed in high quantities over an extended period of time (as is frequently the case during famine), "lathyrism" can result in permanent paralysis and brain damage [12]. According to a report by Abd El Moneim et al. [13], grass pea seeds should have an β-ODAP level of less than 0.22% for safe consumption to reduce the danger of lathyrism. Environmental conditions have a significant impact on the amount of β-ODAP content in grass pea seeds [4]. Its concentration varies commonly among both genotypes and environments [14]. Further domestication and improving of this crop for food (as low β-ODAP) and fodder (as high as biological and seed yield) have been made necessary [15]. Therefore, generating germplasm/cultivars with a low β-ODAP content should be the main goal of both traditional and contemporary breeding programs on Lathyrus [15]. Additionally, the majority of traditional breeding programs for grass peas have emphasized using the selection criterion to increase yield (number of branches per plant). The single node double blooms or pods, higher protein content, 100-seed weight, and forage traits are also important characteristics that can be used in grass pea breeding studies [15,16].

The improvement of quantitative traits related to yield and quality is the main target of breeding programs [17]. With the use of only few elite lines and/or cultivars make a limited contribution to the improvement studies because of their narrow genetic base [18]. Selection from a collection with high diversity makes it more possible to discover the desired traits [19]. Lots of genetic diversity studies have been conducted in grass pea for different regions [5,20–26] to find new traits and develop cultivars in the respective region. However, there is no study which was conducted in two different climatic conditions (lowland and highland) in grass pea. From this perspective, we evaluated a total of 94 grass pea accessions with agro-morphological traits, nutritional contents and β-ODAP contents in lowland and highland environmental areas. The evaluation of agronomic, food and forage traits for economic importance should be useful for choosing the appropriate genetic resources for crop improvement.

#### **2. Materials and Methods**
