Evaluation of Genotype × Environment Interaction and Stability Analysis of Grain and Forage Yield of Grass Pea (Lathyrus sativa L.) Genotypes

Considering the requirement of the country to meet the nutritional needs of the society and the nutritional needs of the existing livestock in order to meet the nutritional needs, it is necessary to introduce cultivars that can be superior to the existing cultivars in terms of adaptability and stability in arid and semi-arid regions. The use of forage plants such as Grass pea can play an important role in crop rotation, soil protection, reducing weeds and diseases due to high adaptability to dry and semi-arid climates and high yield potential, nitrogen fixation, tolerance to drought and salinity. This research was carried out with the aim of evaluating the interaction effect of genotype × environment and the stability of forage and grain yield of Grass pea genotypes in different regions of the country.

This study was carried out with 16 advanced Grass pea lines in Gachsaran, Mehran, Shirvan Cherdavel and Kohdasht stations for three crop years in the form of a randomized complete block design with three replications. Each genotype was cultivated in 6 lines with a length of 7.03 meters and a distance of 0.25 cm from each other. After analyzing the composite variance for different years in different regions, mean comparison was done using the minimum significant difference method at 5% and 1% probability levels. To analys the stability and compatibility of lines, were used the stability methods of Francis and Kanenberg, Eberhut and Russell, Rick's equivalence, Shokla's stability variance, Plasted and Patterson's stability parameter, Finley and Wilkinson, Perkins and Jinks, Gang's total ranking, and the single-variable, non-parametric method, Nassar- Han and Tanazaro.

The results of composite variance analysis of forage yield and grain yield showed that the simple effect of year, genotype, location and the genotype × location interaction effect for both traits were statistically non-significant, and the interaction effect of year × genotype was significant for forage yield and non-significant for grain yield. It was meaningful. The three-way effect of year × location × genotype was not significant at statistical probability levels for forage; but it was significant for grain yield. The forage yield for kholer lines from 12839 kg ha-1 for line number 5 to 16680 kg ha-1 for genotype number 10 with 11.5% drop and 15% superiority compared to Naghadeh, respectively. Also, in terms of grain yield, Grass pea lines fluctuated from 1239 kg ha-1 for line No. 7 to 1723 kg ha-1 for Line No. 10 with a 2% drop and 36.3% superiority compared to Naghadeh. The results of the stability analysis of forage yield showed that in terms of the Coefficient of variation parameter, genotypes 16, 5 and 10, in terms of Phenyl Wilkinson genotypes 15, 2, 13, in terms of Shokla genotypes 14, 9, 6, and in terms of Rick's equivalence, genotypes 14, 9, 6, and 13 were the most stable genotypes. The analysis of grain yield stability by univariate method showed that in terms of Coefficient of variation, genotypes 11, 12, 3, in terms of Phenyl Wilkinson, genotypes 13, 12, 4, 5, 6, in terms of Shukla's, genotypes 7, 12, 5, 6, and in terms of Rick's equivalence, genotypes 7, 12, 5, 6, and 8 were determined to be the most stable Grass pea genotypes.

Based on the obtained results, in terms of forage yield lines No. 1, 10, 3, 9 and 15 and in terms of grain yield genotypes No. 12, 15, 8, 10 and 7 had high stability and yield compared to other genotypes. In general, considering all parameters of stability and compatibility, lines number 1, 10, 12, 15, 8, 7 and 9 were selected as the most stable lines, and genotypes No. 10 and 15 were suitable for both forage and seed.