Analysed data of each environment indicated that genotypes were found to be significant in all the six environments revealed greater magnitude of genetic variation for seed yield. Pooled analysis of variance for seed yield (Table 2) indicated that the genotypes, environments and genotype x environment were significant indicating the presence of variation among genotypes, environments and influence of G×E interaction.
Both linear and non linear components were found to be significant indicating the presence of both stable and non stable genotypes which was also confirmed by
Manivannan et al. (2023). Stability parameters such as mean (xi), regression coefficient (bi) and deviation from regression (S
2di) are considered to assess the stability of different genotypes for seed yield as suggested by
Eberhart and Russel, (1966). The genotypes were categorized into three groups high yielders (939-1136 kg/ha), medium yield (827-880 kg/ha) and low yielders (742-811 kg/ha). Among the genotypes, MGG-556, MGG-570, MGG-564 and MGG-571 recorded high mean yield, regression coefficient more than unity (bi>1) and non significant S2di value indicating that these varieties perform better under good environment and were stable (Table 3). The genotype G9 (MGG-385), G4 (MGG-573) has recorded high yield, regression coefficient (bi=1) and non-significant S
2di values, indicating these genotypes have an average response to environment and stable due to predictable nature and perform better across environments. The entries G13(MGG-295) and G6(MGG-576) and G1(MGG-563) recorded medium yield, bi=1 and non-significant S
2di can perform better under poor environments and stable. The genotype G15 (VBN-4) has recorded bi value nearer to unity and significant S
2di value indicating that this variety is suitable for good environment and unpredictable. The genotypes IPM-2-14, WGG-42, MGG-562 and MGG-565 were poor yielders and recorded non significant S
2d and less regression coefficient (bi<1), hence seed yield did not improve with the improvement in the environment. However, due to the fact that the G×E conserts of both additive and multiplicative model, the recent researchers used the AMMI, GEE biplot and WAAS models. Hence the present data was used to analyze both models to compare the results.
The analysis of variance for AMMI analysis elucidated that the significant difference existed among genotypes, environments and genotypes x environment interaction and witnessed the considerable influence of environments and interaction of genotypes with environments in expressing of the grain yield (Table 4). Further, genotypes contributed 13.18%, environments contribute (55.47%) more in total sum of squares followed by genotype x environment interaction (20.48%) revealing that genotypic architecture of the genotype, environment and their interaction in manifestation of the trait. The larger portion of the yield variation explained by environments indicated that the environments causing the most of the variation for seed yield. The seed yield over environments ranged from 588 kg/ha in Karimnagar (E1) to 1294 kg/ha in Tornala (E4). A large proportion of yield variation explained by environments indicated thet the environments were diverse with large difference among environments causing the most of the variation for grain yield. The genotypic seed yield ranged from 743 kg/ha G11(IPM 2-14) to 1136 kg/ha G7(MGG-556). G×E interaction was a crossover type with different yield ranking of genotypes across environments. The significant interaction in genotype and environment for yield validated the need to take more care while selecting the promising genotypes by considering stability and adaptability. Significant differences across locations were also earlier reported by
Sanasam et al. (2025) using AMMI model. With further division of GGE using AMMI analysis, two significant principal components were separated explaining 69.7% of variance interaction (PCI 42% and PC2 27.7%). Earlier reports confirmed that in most of the cases the maximum genotype and environment interaction could be explained through using the first three PCA’s.
Naresh et al. (2025);
Sanasam et al. (2025) in greengram, Chandramohan
et al.
(2023) in rice evaluated the interactions between genotypes and environmental axes IPCA1 and IPCA2. While
Mahalingam et al. (2019) reported IPCA1 alone may decide the G×E interaction in this study, whereas
Manivannan et al. (2023) also reported that IPCA1, IPCA2 and IPAC3 contribute 46.3%, 37.5% and 16.0% towards interactions respectively.
The results of the AMMI analysis further enlightened the relative contribution of the first two IPCA axes to the interactive effects by plotting with genotype and environment means as presented in Fig 1. In the biplot, environments are designated by the letter E followed by number 1 to 6 suffix (E1-E6) while, genotypes represented by numbers for 1 to 15 (G1-G15). When a variety and environment have the same sign on PCA1 axes their interaction is positive and if opposite their interaction is negative. Thus if a variety has a IPCAI score near to zero, it has small interaction effect and committed to the stable over wide environments. Conversely, varieties with high mean yield and large IPCA1 scores were considered as explicitly adapted to specific environments. Similar views were expressed in their studies by
Manivannan et al., (2023); Shobanadevi et al., (2023); Naresh et al. (2025) and
Sanasam et al. (2025).
The greengram genotypes G7(MGG-556) recorded high seed yield followed by G12 (MGG-570), G15 (VBN-4), G9(MGG 385) and G8 (MGG-571). In the present study G7(MGG556) has recorded highest seed yield value (horizontal axis) with positive IPCA1 score (vertical axis) of 9.91 followed by G12 (MGG-570) and G14 (MGG-564) indicating positive genotype × environmental interaction, hence these genotypes can be recommended for cultivation under favorable environments. The genotype G9(MGG-385) have recorded nearly zero IPCA1 score (0.03) (Table 5) indicating minimal interaction with the environment in which genotype showed above average yield and identified as most stable genotype with less yield variation across different environments. The other genotypes had less than the mean seed yield and found specific adoption to few tested environments. Most of the genotypic stability was attributed by environments E2 (Madhira) (-2.74) and E4 (Tandur)(-5.92) which had the lowest IPCA 1 scores had very little interaction effects and thus the performance of all genotypes in these environments was quite well. Hence these were considered as favorable environments for all the tested genotypes. With respect to GEI contribution E5 (Tornala) (17.84) and E3 (Palem) (13.99) exhibited the highest level of contribution as indicated by their high IPCA1 scores had the greatest effect on the G×E, so the comparative genotypes ranking in these environments were unstable.
The environment having the long spokes is said to be more interactive (Fig 2) and among the environments E2 (Madhira) and E5 (Tornala) has the long spokes than E6 (Warangal), E4 (Tandur) and E3 (Palem) environments considering the genotypes. Those genotypes are nearer to origin are considered to be less interactive with environments. Based on this criterion genotypes G9 (MGG 385) within the orient and G13 (MGG295) close to the biplot origin had a smaller spoke of G´E were considered as less interactive genotypes with environments and generally stable in all environments. The genotypes G7(MGG-556), G12(MGG-570), G8(MGG-571) and G14(MGG-564) are far from the origin had the most variation due to environmental changes.
Based on AMMI biplot 1 and 2, the genotype MGG-385 was identified as stable genotype with high seed yield. E4 (Tandur) and E3 (Palem) environments where the vectors were shortest and could discriminate between genotypes. In this graph, sites with short spokes did not exert strong interactive forces. Those with long spokes exerted strong interaction.
To get a clear cut ranking of the genotypes regarding stability, AMMI stability value (ASV) stability indexes were computed (Table 5). G9 (MGG-385) showed the minimum ASV (2.117) value and ranked as number one regarding stability, while G8 (MGG 571) has showed highest ASV (21.83) value and showed poorest stability.
GGE biplot helps in identifying GxE interaction pattern of data and provides us with clear picture of which genotype perform best in which environments and thus facilitates mega environment identification than AMMI (Table 4). Otherwise, both GGE and AMMI models are equivalent as far as their accuracy is considered
(Gurmu et al., 2012). GGE biplot analysis also enables visual assessment of adaptability and stability. GGE biplot is presented with two principal components explaining a total of 75%. GGE variation (PC1=55.53%; PC2=19.9% represented in Fig 3. The first Principal component is represented on the X-axis and across its values is estimated yield
i.e., genotypes that have higher PC1 values are considered to be more productive. The second principle component is represented on the Y-axis and presents the stability of the genotypes. Estimation of yield and stability of genotype was done by using so called AEC (average coordinates of the environment) method (
Yan, 2001;
Yan and Hunt, 2001). By projecting the genotypes on AEA axis, the genotypes are ranked by yield where the yield increases in the direction of arrow. Single arrowed lines in the Average Environment Coordination Abscissa (AEC) points to higher mean seed yield across environments (Fig 4). The double arrowed line in the AEC Coordinate representing highest variation in either direction. Hence, the genotypes G9 (MGG-385) and G13 (MGG-295) are stable, whereas others are highly interactive with environments. Hence, the genotypes G9 (MGG-385) and G13 (MGG-295) are found to be ideal with high mean and stability.
Discriminating and representativeness are the most important parameters of the GGE biplot when evaluating an environment. In
Yan and Tinker, (2006) model a long environmental vector had high discriminating ability and short one had low discrimination therefore as shown in Fig 5 among tested locations E2(Madhira) and E5(Tornala) were identified as the potential environments for discriminating ability and representativeness.
Yan et al. (2000);
Laxuman et al., (2025) and
Sanasam et al., (2025) also emphasized that the environments with long vectors are more discriminating and representativeness for consideration in future studies. Among the environmental vectors E3-E5, E2-E4, E2-E6 are found to be positively correlated (acute angle) E1-E6, E1-E2, E1-E3 vectors from obtuse angle and hence they are negatively correlated. E3-E6 form right angle and hence not correlated between them. Longer the distance between environmental vectors indicates that they are dissimilar in discriminating the genotypes. From the Fig 5, E2-E4 form one group whereas E1-E4 form two different groups. Environmental vector of E5 is the longest indicating that it is the environment with most discriminating ability followed by E2 (Madhira) and E3 (Palem) while E1 (Karimnagar) and E4 (Tandur) is least discriminating environments.
What won where view of the GGE biplot is the best model for multi environment data for classifying the environments and also to select best performing genotypes in each
(Yan et al., 2000). The equality line divides biplot into different sectors and winning genotypes are located on vertex of each sector. Genotypes located on the vertices of the polygon performs either the best or the poorest in one or the more environments. Vertex genotypes have longest vectors in their respective direction which is a measure of the responsiveness of the environment. The vertex genotypes G1 (MGG-563), G8 (MGG-571), G12 (MGG-570), G15 (VBN-4), G11 (IPM 2-14), G3 (MGG-565) and G5 (WGG-42) have longest vectors in their respective directions (Fig 6). The genotypes G9 (MGG-385) and G13 (MGG-295) considered as stable and performed better under all the environments. The genotypes G3 (MGG-565), G5 (WGG-42) and G11 (IPM 2-14) were best performers in mega environment consisting in E1(Karimnagar) while G1 (MGG-563), G8 (MGG-571) and G12 (MGG-570) perform well in mega environments consists of E5(Tornala), E3 (Palem) and E4 (Tandur) and G15(VBN-4) in E1 (Karimnagar) and E6 (Warangal) are the winning genotypes. The other genotypes G4 (MGG-573), G14 (MGG-564), G12 (MGG-570), G6(MGG-576) and G2(MGG-553) are poorest performers of all the environments because there is no environment in their sector. Hence for different mega environments, different genotypes have to be selected and deployed for each.
Y×WAAS biplot was divided into four quadrants which represented the classification of genotypes and environments (Fig 7). The quadrants in the graph represent (QI and QII) higher mean, (QIII and QIV) lower means. (Q1 and QIV) positive IPCA1 and (QII and QIII) negative IPCAI scores (Table 5). G3(MGG-565) and G1(MGG-563) grouped in the I quadrant were unstable genotypes with productivity below the grand mean and E1 environment was included with high discrimination ability as had high WAAS value. In quadrant II, G15 (VBN-4), G12 (MGG-570) and G8 (MGG-571) were present which were unstable genotypes, but had seed yield above the highest average value. The environments E2(Madhira), E3 (Palem), E5(Tornala) and E6(Warangal) included in the II quadrant provides high seed yield, they presented a good discrimination ability as had high WAAS values except E2 (Madhira). Genotypes G2 (MGG-553), G5 (WGG-42),G6 (MGG-576),G10 (MGG-562),G11 (IPM-2-14), G13 (MGG-295) included in the III quadrant had a low seed yield, low WAAS values so considered stable but no environment with high discrimination ability was identified. The genotypes G4 (MGG-573), G7 (MGG-556), G9 (MGG-385) and G14 (MGG-564) present in the IV quadrant were broadly adopted but their performance regarding yield were just nearer to mean. AMMI biplot found E2(Madhira) and E4 (Tandur) as favorable while E5 (Tornala) and E6 (Warangal) with the greatest GEI as unfavorable for testing. However, Y×WAAS grouped the environment only based on discriminating ability, so in this biplot E3 (Palem), E5 (Tornala) and E6 (Warangal) all grouped in II quadrant with good discriminating ability. Further, these environments have high WAAS values indicating that they have higher interactions with the studied genotypes. The higher mean performance of these environments regarding seed yield indicated that their influence on the yield was positive. Similar results regarding GEI from the WAAS biplot were also observed for chickpea genotypes by
Arshad et al., (2024).