نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Introduction
Global agriculture confronts critical challenges driven by population growth and the scarcity of vital resources, particularly water and soil. In Iran, these pressures are exacerbated by climatic volatility and a reliance on imported protein inputs, rendering the adoption of resilient, low-input forage legumes essential. The pea (Pisum sativum L.) is a promising candidate owing to its genetic diversity, high biomass potential, and soil-improving properties via nitrogen fixation. Nevertheless, the scarcity of improved varieties adapted to Iran's diverse climates constrains its cultivation. Successful production depends on selecting cultivars with robust vegetative growth and delayed physiological maturity to maximize dry matter accumulation. However, these traits are governed by complex interactions between genetic factors and environmental variables, such as temperature and photoperiod. Furthermore, forage quality typically declines with maturity due to lignification. Consequently, a comprehensive multi-environmental evaluation is essential to identify cultivars that achieve an optimal balance of high yield, stability, and nutritional quality. The objective of this study is to address existing knowledge gaps via a rigorous multi-year, multi-location trial that assesses agronomic performance, stability, and forage quality of distinct pea cultivars across the varied agro-ecological zones of Iran.
Materials and Methods
A field experiment was conducted across four representative locations: Karaj (cold semi-arid), Gorgan (humid Caspian), Kermanshah (cold semi-arid Mediterranean), and Parsabad (warm semi-arid temperate) during the 2023-2024 and 2024-2025 growing seasons. The study utilized a randomized complete block design with four replications to evaluate two imported forage pea cultivars from Turkey, namely Zerre and Gap pembesi, alongside registered cultivars (Arda, Beren and Tashkent). Agronomic management, including irrigation and weed control, was uniformly applied across all treatments in accordance with local recommendations. Evaluated traits included fresh and dry forage yield, plant height, establishment percentage, and phenological characteristics. To assess nutritional quality, random samples of approximately 500 grams were collected from the first harvest. Following drying and milling, qualitative parameters, including crude protein (CP), water-soluble carbohydrates (WSC), crude fiber (CF), acid detergent fiber (ADF), and total ash content, were analyzed using near-infrared spectroscopy (NIRS; PerCon Inframatic 8620). Statistical analysis involved a combined analysis of variance (ANOVA) across years and locations using SAS software (version 9.4). Mean comparisons were performed using the Least Significant Difference (LSD) test at the 5% probability level. Additionally, GGE-biplot analysis was employed to assess cultivar stability and cultivar-by-environment interaction.
Results and Discussion
Analysis of variance revealed significant effects for location, year, cultivar, and their interactions on most traits, highlighting the substantial impact of environmental heterogeneity on forage pea performance. Descriptive statistics showed high variability in yield traits, reflecting considerable genetic diversity and environmental sensitivity. The location effect was particularly pronounced for yield; Gorgan exhibited the highest fresh and dry forage yields due to its favorable humid climate and fertile soil, while Karaj showed the lowest yields, likely due to moisture limitations and heat stress. Kermanshah and Parsabad demonstrated intermediate performance with acceptable stability. Among the cultivars, Gap pembesi distinguished itself with the highest fresh and dry yields, superior plant height, and establishment percentage. Its late-maturing phenotype extended the vegetative period, facilitating greater photosynthetic accumulation. GGE-biplot analysis confirmed its broad adaptability and general superiority. Beren ranked second, driven by vigorous vegetative growth and strong regrowth ability. Conversely, early-maturing cultivars, Tashkent and Arda, produced lower biomass. While their shorter cycle suits regions with constrained growing seasons, their yield potential was lower in this study. Zerre demonstrated a superior nutritional profile, with high CP, optimal WSC, and moderate ADF, resulting in high digestibility. In contrast, Gap pembesi exhibited higher fiber fractions, resulting in lower digestibility compared to Zerre. Tashkent exhibited the lowest nutritional quality. These findings suggest that while late-maturing cultivars like Gap pembesi are ideal for maximizing biomass, cultivars like Zerre offer superior forage quality essential for animal nutrition.
Conclusions
This comprehensive multi-environment study provides key insights into the agronomic and qualitative performance of forage pea cultivars in Iran. The observed substantial cultivar-by-environment interaction dictates the need for region-specific cultivar recommendations. Based on the integration of yield data, stability analysis, and nutritional quality assessments, Gap pembesi is identified as the superior cultivar for general cultivation. Its outstanding biomass yield, plant height, establishment rate, and wide adaptability across different climates position it as a top choice for enhancing domestic forage output. Beren is also recommended as a complementary cultivar, particularly for temperate regions, due to its vigorous vegetative growth and regrowth capacity. However, for farming systems prioritizing forage quality over sheer biomass quantity, Zerre offers a distinct advantage with its high protein content and superior digestibility. Ultimately, decisions regarding cultivar selection must be based on production targets, regional climate, and growing season duration. This study establishes a solid foundation for future breeding programs and extension services by promoting the adoption of high-yielding, stable, and qualitatively superior forage pea cultivars to ensure the sustainability of Iran's livestock sector. This study lays a solid foundation for future breeding programs and extension services, promoting the adoption of high-yielding, stable, and qualitatively superior forage pea cultivars to ensure the sustainability of Iran's livestock sector.
کلیدواژهها English
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