Soybean ( <i>Glycine max </i> L. Merr.) adaptation to new environments has been hard to predict based on maturity group. The aim of this study was to evaluate the performance of 14 soybean genotypes, from the Soybean Breeding Program of the Federal University of Uberlandia, in their adaptive capacity and seed yield stability at 3 locations and 2 growing seasons. For the adaptability and stability analysis the Toler and Centroid methods were used; 5 genotypic groups were identified in the first whereas 4 groups were identified in the latter. By the Toler method group A was composed by 4 genotypes, UFU-001, UFU-003, UFU-0010, and UFU-001. They showed a convex pattern of adaptability and stability. In contrast, the genotypes UFU-008 and UFU-0013 were classified in Group E with a concave pattern of adaptability and stability. Regarding results from the Centroid method, the Genotype UFU-002, with higher seed yield than average, was the only genotype in Ideotype VI with moderate adaptability to favorable environments. In contrast, 10 genotypes were included in the Ideotype V, of medium general adaptability. The genotypes UFU-001, UFU-002, UFU-006, UFU-0010, and UFU-0011 were recommended for use in the Brazilian Cerrado growing region. These genotypes had high seed yield potential in high quality environments.
The soybean (Glycine max L. Merr.) crop has been grown in a wide range of latitudes in Brazil ranging from 4˚N at Pacaraima―RR to 33˚S at Santa Vitoria do Palmar―RS [
Through a simple joint analysis of variance among G × E trials repeated in two or more environments, the G × E interactions could be detected [
Among the methodologies for adaptability and stability analysis, those using linear regression have been the most widely used [
In the nonlinear regression method presented by Toler [
There is a current trend towards the use of multivariate methods; one of the reasons is the possibility to visualize a genotype performance in a given environment in a dimensional space [
The objective of this study was to assess the adaptability and stability of yield in Brazilian experimental lines of semi-late and late maturing in three locations over two years.
The trials were conducted in 2005/2006 and 2007/2008 growing seasons at 3 locations in Brazil which were at Porangatu―GO, Porto Alegre do Norte―MT and Uberaba―MG. They are part of the Cultivation and Use Value (CUV) network trials of the of the Federal University of Uberlandia breeding program, which aims at improving yield and oil content of soybeans.
Thirteen experimental soybean lines of semi-late/late maturity were evaluated and the commercial cultivar “MSOY-8914” was used as check. The experiments were carried out in randomized complete blocks with 3 replications. The experimental plot consisted of 4 rows of soybean plants of 5.0 meters long, spaced 0.50 meters apart. The two central rows of each plot were harvested, but not the 0.50 meters at each end of the rows. The harvestable area of each plot was 4.0 square meters.
An analysis of variance was carried out for each of the 6 environments (i.e. Porangatu―GO, Porto Alegre do Norte―MT, Uberaba―MG in the 2005/2006 and 2007/2008 growing seasons). Genetic and statistical analysis was performed by the GENES software [
Preceding the joint analyses, variance homogeneity test was performed. This was based on the criterion of the maximum relation between the highest and lowest residual mean squares equaling 7 [
where:
Yij: is the average response of genotype i at environment j (
Zj: is a dummy indicative variable being Zj = 1 when
A―convex response and doubly desirable;
B―simple linear response and just desirable at high quality environments;
C―simple linear response does not deviate from average response;
D―simple linear response and just desirable at low quality environments;
E―concave response and doubly undesirable.
These response patterns are assumed according to a hypothesis test based on Student’s t test. First the hypothesis H0:
Therefore, the criteria for classification of genotypes into the 5 groups can be summarized as follows:
The Centroid method is a multivariate analysis proposed by Rocha et al. [
Using the statistical software GENES [
where:
Yij: mean of genotype i at environment j;
Y: total of all observations;
a: number of environments;
g: number of genotypes.
Thus, the mean Cartesian distance of each genotype to reference ideotypes is calculated by the following formula:
where:
Pik: probability that genotype i is similar to ideotype k;
dik: distance from genotype i to ideotype k generated in the Cartesian plane.
The analysis of variance for each environment was carried out and the results are shown in
Analyzing soybean genotypes of semi-early and semi-late maturity Rocha [
The relation between the higher and lower residual mean squares of all environments was 2.55. Therefore experimental residual variances were considered homogeneous once the maximum accepted is 7 [
The environmental index proposed by Finlay and Wilkinson (1963) was required for both methods used. In the Toler method this index was
Growing Season | Location | Ῡ.i. | MSE | CV (%) |
---|---|---|---|---|
2005/2006 | Porangatu | 2408.33 | 208743.99 | 18.97 |
2005/2006 | Porto Alegre do Norte | 3723.97 | 273063.45 | 14.03 |
2005/2006 | Uberaba | 2535.84 | 169537.26 | 16.24 |
2007/2008 | Porangatu | 3048.51 | 377481.97 | 20.15 |
2007/2008 | Porto Alegre do Norte | 2941.67 | 298804.94 | 18.58 |
2007/2008 | Uberaba | 3061.94 | 433065.77 | 21.49 |
Source of Variation | df | Sum of Squares | Mean of Square | F | Pr > F |
---|---|---|---|---|---|
(Replications/Years)/Locations | 12 | 8782216.43 | 731851.37 | ||
Genotypes (G) | 13 | 6110077.49 | 470005.96 | 1.60 | 8.98ns |
Years (Y) | 1 | 1032102.40 | 1032102.40 | 1.41 | 25.80ns |
Locations (L) | 2 | 18349422.13 | 9174711.07 | 12.54 | 0.12** |
G × Y | 13 | 12144888.02 | 934222.16 | 3.18 | 0.03** |
G × L | 26 | 20230177.29 | 778083.74 | 2.65 | 0.01** |
Y × L | 2 | 26238641.82 | 13119320.91 | 17.93 | 0.02** |
G × Y × L | 26 | 13664764.08 | 525567.85 | 1.79 | 1.60* |
Error | 156 | 45778132.07 | 293449.56 | ||
Overall Average | 2953.38 kg・ha−1 | ||||
CV (%) | 18.34 |
*, **: significant at 5% and 1% levels of probability, respectively.
Growing Season | Location | Environment | Ῡ.i. | Ij |
---|---|---|---|---|
2005/2006 | Porangatu | 1 | 2408.3 | −545.04 |
2005/2006 | Porto Alegre do Norte | 2 | 3724.0 | 770.59 |
2005/2006 | Uberaba | 3 | 2535.8 | −417.54 |
2007/2008 | Porangatu | 4 | 3048.5 | 95.14 |
2007/2008 | Porto Alegre do Norte | 5 | 2941.7 | −11.71 |
2007/2008 | Uberaba | 6 | 3061.9 | 108.56 |
Therefore, all of them presented negative environmental indices. On the other hand the most favorable environment was Porto Alegre do Norte 2005/2006 followed by Porangatu 2007/2008 and Uberaba 2007/2008. Consequently, all locations showed positive environmental indices.
The adaptability and stability analysis according to the Toler method assumed 5 possible groups for each ge-
notype. The estimated parameters
their behavior in favorable and unfavorable environments was similar, hence they classified in Groups B, C or D.
However, 6 genotypes presented significant results for
nonlinear pattern responses which resulted in a bi-segmented model. Notably, the genotypes UFU-001, UFU-003, UFU-0010, and UFU-0011 were classified in Group A which means that they were well adapted to high quality environments (e.g. high soil fertility, controlled biotic and abiotic stresses), and they needed these types of environment to express their maximum yield potential [
Also in the bi-segmented model were the UFU-008 and UFU-003 genotypes, however they were also classified in Group E, for good performance in the most unfavorable environments, but a poor in the most favorable. A single straight line was able to explain the behavior of Groups B, C and D of genotypes. In order to have the
Genotype | Ῡ.i. | Group | |||||
---|---|---|---|---|---|---|---|
UFU-001 | 3149.6 | 2869.2 | 0.55 | 2.46** | 1.91* | 1.86** | A |
UFU-002 | 3229.3 | 3229.3 | 2.49* | 0.99 | −1.50 | 1.45 | C |
UFU-003 | 2775.2 | 2484.3 | −0.06 | 1.92* | 1.98* | 1.27 | A |
UFU-004 | 3131.2 | 3175.2 | 0.74 | 0.44 | −0.30 | 0.54 | C |
UFU-005 | 2950.9 | 2950.9 | 1.88 | 0.70 | −1.18 | 1.20 | C |
UFU-006 | 2985.9 | 2985.9 | 1.47 | 1.95* | 0.48 | 1.82** | B |
UFU-007 | 2824.0 | 2824.0 | 0.79 | 0.73 | −0.06 | 0.77 | C |
UFU-008 | 2684.5 | 3172.8 | 2.31* | −1.01** | −3.32** | −0.02** | E |
UFU-009 | 2915.4 | 2915.4 | 0.72 | 1.44 | 0.72 | 1.24 | C |
UFU-0010 | 2985.7 | 2689.9 | 0.23 | 2.25** | 2.01* | 1.55 | A |
UFU-0011 | 3112.3 | 2690.4 | −0.30* | 2.57** | 2.87** | 1.63* | A |
UFU-0012 | 2837.2 | 2837.2 | 0.12 | −0.07* | −0.19 | −0.07** | D |
UFU-0013 | 2983.8 | 3250.2 | 1.46 | −0.35** | −1.81* | 0.27* | E |
MSOY-8914 | 2782.5 | 2782.5 | 1.59 | −0.02* | −1.61 | 0.48 | C |
*, **: significant at 5% and 1% levels of probability, respectively, through student’s t test.
genotypes classified in these groups the estimates for
we had for UFU-002, UFU-004, UFU-005, UFU-007, UFU-009 and MSOY-8914 genotypes, they were classified in Group C of general adaptability. This group is characterized by good plasticity and capability to adjust to environment variations [
For those genotypes whose estimates for the
of specific adaptability to unfavorable environments.
These response patterns can be better visualized in
In
Centroid adaptability and stability analysis differ from other methods by considering genotypes with maximum specific adaptation, those with maximum yields in a certain group of environments (favorable or unfavorable) and minimum yields in another group [
Notably UFU-002 genotype was the only one classified in Ideotype VI. The response pattern in this group considered maximum yields in favorable environments and the mean yield in unfavorable ones. This Ideotype was a modification of the original method proposed by Rocha et al. (2005) and it allowed a more biological sense to the analysis as the addition of intermediate ideotypes avoids comparisons with extreme genotypes [
Analyzing
Using Centroid method with 4 ideotypes Oliveira et al. [
Genotype | Ῡ.i. | Classification | Probability |
---|---|---|---|
UFU-001 | 3149.6 | V | 0.20 |
UFU-002 | 3229.3 | VI | 0.23 |
UFU-003 | 2775.2 | V | 0.27 |
UFU-004 | 3131.2 | VII | 0.24 |
UFU-005 | 2950.9 | V | 0.26 |
UFU-006 | 2985.9 | V | 0.24 |
UFU-007 | 2824.0 | V | 0.34 |
UFU-008 | 2684.5 | IV | 0.19 |
UFU-009 | 2915.4 | V | 0.27 |
UFU-0010 | 2985.7 | V | 0.24 |
UFU-0011 | 3112.3 | V | 0.20 |
UFU-0012 | 2837.2 | V | 0.22 |
UFU-0013 | 2983.8 | V | 0.24 |
MSOY-8914 | 2782.5 | V | 0.25 |
IV: minimum adaptability; V: mean general adaptability; VI: mean specific adaptability to favorable environments; VII: mean specific adaptability to unfavorable environments.
Component | Proportion (%) | Cumulative (%) |
---|---|---|
1.9495 | 32.49 | 32.49 |
1.82 | 30.33 | 62.82 |
0.92 | 15.34 | 78.16 |
0.64 | 10.59 | 88.75 |
0.40 | 6.64 | 95.39 |
0.28 | 4.61 | 100.00 |
The genotype UFU-008 was classified by the Toler and Centroid methods as being of low adaptability capacity. An agreement was also reached by both methods relating to the genotypes UFU-005, UFU-007, UFU-009 and MSOY-8914. They were classified as being of general adaptability and unaffected by G × E interactions. The mean grain yield of the genotypes UFU-001, UFU-002, UFU-006, UFU-0010, and UFU-0011 was above Brazil’s soybean mean yield in the 2012/2013 growing season (2939 kg∙ha−1). As such, these genotypes may be adapted to high quality environments where they are likely to express their maximum yield potential.
This study was partially funded by a scholarship from the Brazilian Coordination for the Improvement of Higher Education Personnel (CAPES―Process BEX 11900/13-0) and supported by the Brazilian National Council for Scientific and Technological Development (CNPq) and by the Research Support Foundation of Minas Gerais State-Brazil (FAPEMIG).