Evaluation of the Genotype × Environement Interaction on Agronomic Traits and Seed Yield Stability in Peanut (Arachis hypogaea L.) Genotypes Using the GGE Biplot Method

Extended Abstract Background: The production of peanuts (Arachis hypogaea L.) as one of the vital industrial plants is affected by the environment, genotype, and their interaction. Therefore, the environment × genotype interaction on peanut yield should be evaluated before the introduction of cultivars. Evaluation of the genotype × environment interaction provides valuable information regarding the performance of plant cultivars in different environments. It plays a crucial role in evaluating the stability of the performance of breeding materials. This experiment evaluated the stability and yield of superior peanut genotypes in three regions of Guilan province, Iran, in the 2018 and 2019 crop years. Methods: In this study, the top 10 peanut genotypes (130, 140, 113, 115, 128, 176, 178, 192, 201, and 208 from ICRISAT) along with the NC2 variety as a control were assessed in a complete randomized block design trial with three replications across three regions Rasht, Masal, and Talash. Each plot comprised six lines, each with 5 m long, 50 cm row spacing, and 20 cm plant spacing. Upon reaching physiological ripeness, a 5-m2 area was harvested from the middle four rows of each plot after removing 0.5 m from both ends to eliminate marginal effects. The plant height (cm), average number of sub-branches per plant, number of pods per plant, and number of seeds per pod were randomly recorded and counted from 10 plants. After drying, biomass, pod, and seed yields were calculated in kg/ha. Following seed separation from the shell, five random samples of 100 seeds were taken from each plot to measure the 100 seed weight (HSW). Additionally, the length and width of peanut pods and seeds were recorded (in mm) using a digital caliper. To determine seed oil percentage, 150 g of peanut seeds were randomly selected from each plot, and their oil percentage was measured using the Soxhlet method after grinding the samples. Composite variance analysis was conducted after ensuring the uniformity of experimental error, and the mean traits were compared using the least significant difference (LSD) method. The stability of peanut genotypes was assessed using the GGE bi-plot analysis. Results: The variance analysis revealed that the interaction of location × genotype significantly affected the peanut plant's height, sub-branches, and pod diameter at a one percent probability level. Additionally, the year × location × genotype interaction significantly affected other traits such as pods per plant, seeds per pod, HSW, pod yield, seed yield, seed oil percentage, oil yield, shell yield, pod length, and peanut seed length and width at the 1% probability level. Notably, genotype 208 in the Rasht region exhibited the tallest average plant height (103.5 cm), which was not significantly different from line 201. Furthermore, the highest number of peanut pods (31.72 pieces) was observed for genotype 128 in the Rasht region in the first crop year, showing no significant difference with line 128 in the first and second crop years. Significant differences were also noted in the number of seeds per pod across different genotypes and regions. For instance, the second crop year in the Rasht region and genotype 113 yielded the highest peanut HSW (71.45 g), which was not significantly different from some lines in the two crop years in the Masal and Rasht regions. Furthermore, the pod yield of genotype 192 in the first crop year was superior in Rasht (5583 kg/ha), Masal (5233 kg/ha), and Talash (4166 kg/ha) regions compared to the other genotypes. Genotype 192 exhibited the highest seed yield (3777 kg/ha) in the first crop year in Rasht, representing a 133% increase compared to the control (NC2). These results underscore the significant influence of climatic conditions on peanut seed yield and the genetic potential variations among different genotypes in diverse regions. Additionally, genotype 192 in the first cropping year and Rasht region attained the highest peanut oil yield (1841 kg/ha), aligning with findings from other researchers regarding varying oil yields among different peanut lines. Conclusion: Based on the findings of this study, all traits measured in peanuts were impacted by the interaction of genotype and environment. Line 192 displayed significantly superior quantitative and qualitative performance of peanut seeds to the NC2 variety, known as the Goli native variety, and the other studied lines. The increase in the number of pods per plant, seeds per pod, and the peanut HSW were important agronomic indicators in improving the performance of line 192 in the Guilan region. The results indicated that the interaction effect of genotype and environment led to changes in the yield components, resulting in changes in the yield of peanut seeds and pods per unit area, with the oil yield increasing in parallel with the grain yield. Using the GGE bi-plot method to evaluate performance stability, peanut line 192 was identified as a high-yielding line with high performance and stability in all environments. Therefore, groundnut genotype 192 is recommended for achieving the highest seed yield in the region's climatic conditions.