Harmonic Mean Of Relative Performance Research Articles

Seleção genotípica de pré-cultivares de feijão carioca e carioca precoce para o Agreste-Sertão de Pernambuco, Brasil

ABSTRACT: Genotype x environment interactions represent a major challenge in identifying and selecting genotypes responsive to different climate and soil conditions. This research evaluated and selected pre-cultivars of carioca bean and early carioca bean based on adaptability, stability, and grain yield. In the 2014 crop season, two regional competition trials were conducted in the state of Pernambuco: carioca beans (14 genotypes in Arcoverde, Belém de São Francisco, Caruaru and São João) and early carioca beans (11 genotypes in Araripina, Arcoverde, and Caruaru) and, in the 2015 crop season, with early carioca beans (11 genotypes in Araripina, Arcoverde, and Brejão). Parameters were estimated by mixed models, and the selection was performed using the Harmonic Mean of Relative Performance of Genetic Values (HMRPGV) method following three strategies: i) selection based on predicted genetic value with no interaction; ii) selection according to predicted genetic value considering each location; and iii) simultaneous selection for grain yield, adaptability, and stability. The environments influenced the phenotypic expression of the carioca and early carioca bean genotypes, representing a specific adaptation. The genotypes BRS Notável, BRS Estilo and BRS Pérola, of carioca beans, and CNFC 15875, BRS Notável and CNFC 15630, of early carioca beans, had the best results in the environments tested, regarding, simultaneously, adaptability to different soil and climate conditions, performance stability, and grain yield.

Genotype-by-Environment Interaction Analysis of Metabolites in Pearl Millet Genotypes with High Concentrations of Slowly Digestible and Resistant Starch in Their Grains.

Genotype × environment interactions (GEIs) should play an important role in the selection of suitable germplasm in breeding programmes. We here assessed GEI effects on pearl millet (Pennisetum glaucum L.) genotypes, selected to possess a high concentration of slowly digestible starch (SDS) and resistant starch (RS) in their grains. Entries were grown in a randomized complete block design with three replications at locations in Bawku-Ghana, Sadore-Niger, Bamako-Mali, Konni-Nigeria, and Gampella-Burkina Faso across West Africa. Harvested grains from these locations were metabolomically profiled using flow injection ionization-high-resolution mass spectrometry (FIE-HRMS). A total of 3144 mass features (m/z) (1560 negative ion mode and 1584 positive ion mode) were detected, of which, 475 m/z were linked to metabolites be involved in starch, antioxidant and lipid biosynthesis, and vitamin metabolism. Combined ANOVA revealed that the GEI was significantly evident for 54 health-benefiting metabolites, many associated with sugar, especially galactose, metabolism. Additive main effects and multiplicative interaction (AMMI) analysis examined genotype variation and GEI effects, which, when combined with principal component analysis (PCA), found that m/z 171.14864 (positive ionisation, propenyl heptanoate) accounted for 89% of the GEI variation along PC1. The AMMI-based stability parameter (ASTAB), modified AMMI stability value (MASV), and modified AMMI stability index (MASI) were then applied to identify stable and high-performing genotypes for all the health-benefiting metabolites. Similarly, the best-linear-unbiased-prediction (BLUP)-based stability estimation was also performed using the harmonic mean of genotypic values (HMGV), relative performance of genotypic values (RPGV), and harmonic mean of relative performance of genotypic values (HMRPGV), to identify genotype rankings across multiple environments. The multi-trait stability index (MTSI) was calculated and found that the genotypes G1 (ICMH-177111) and G24 (ICMX-207137) were the most stable and were the best mean performers across 52 health-benefiting metabolic traits. These findings demonstrate the potential of G × E assessments on the delivery of health-benefiting metabolite-rich grains in future varieties and hybrids of pearl millet.

Genetic parameters, yield adaptability and stability of common bean obtained through mixed models analyses

The common bean provides a diet rich in vitamins, fiber, minerals and especially in proteins, which can provide food security for poor people in many countries. With the increase in demand for food production, cultivars with high grain yield potential that can be planted in different environments have been the focus of common bean breeding programs. Therefore, this study aimed to evaluate genetic parameters, grain yield, adaptability and stability simultaneously of common bean lines that compose the Value for Cultivation and Use trials of the South region of Brazil. The experiments were conducted in 13 environments in the states of Paraná, Santa Catarina and Rio Grande do Sul. The analysis of adaptability and stability were performed The common bean provides a diet rich in vitamins, fiber, minerals and especially in proteins, which can provide food security for poor people in many countries. With the increase in demand for food production, cultivars with high grain yield potential that can be planted in different environments have been the focus of common bean breeding programs. Therefore, this study aimed to evaluate genetic parameters, grain yield, adaptability and stability simultaneously of common bean lines that compose the Value for Cultivation and Use trials of the South region of Brazil. The experiments were conducted in 13 environments in the states of Paraná, Santa Catarina and Rio Grande do Sul. The analysis of adaptability and stability were performed using mixed linear models by the Residual Maximum Likelihood and the Best Linear Unbiased Predictor for predicting the genotypic values through Selegen statistical program. The selective accuracy of genotypes for their genotypic values was 87% and the broad-sense heritability for grain yield was 13%. The genotypes CHC 98-42, BRS Esteio, CNFP-10794, CHP 01-238, FT 08-75, IPR Campos Gerais, LP 09-40, CNFC 10762, C 4-7-8-1-2 and LEC 01-11 were superior based on the method of Harmonic Mean of Relative Performance of Genotypic Values. These genotypes presented a higher mean grain yield in comparison to the other evaluated genotypes, and could be recommended for cultivation in these regions. In addition, it was possible to obtain genetic gains of up to 9.5% for the CHC 98-42 line, showing its high genetic potential.

Comparative Study of AMMI- and BLUP-Based Simultaneous Selection for Grain Yield and Stability of Finger Millet [Eleusine coracana (L.) Gaertn.] Genotypes.

Finger millet, an orphan crop, possesses immense potential in mitigating climate change and could offer threefold security in terms of food, fodder, and nutrition. It is mostly cultivated as a subsistence crop in the marginal areas of plains and hills. Considering the changes in climate inclusive of recurrent weather vagaries witnessed every year, it is crucial to select stable, high-yielding, area-specific, finger millet cultivars. Sixty finger millet varieties released across the country were evaluated over six consecutive rainy seasons from 2011 to 2016 at the Agricultural Research Station, Vizianagaram. The genotype × environment interaction (GEI) was found to be significant in the combined ANOVA. Furthermore, the Additive Main effects and Multiplicative Interaction (AMMI) analysis asserted that genotypes and the GEI effects accounted for approximately 89% of the total variation. Strong positive associations were observed in an estimated set of eleven stability parameters which were chosen to identify stable genotypes. Furthermore, Non-parametric and Parametric Simultaneous Selection indices (NP-SSI and P-SSI) were calculated utilizing AMMI-based stability parameter (ASTAB), modified AMMI stability value (MASV), and Modified AMMI Stability Index (MASI) to identify stable high yielders. Both methods had inherent difficulties in ranking genotypes for SSI. To overcome this, the initial culling [i.e., SSI with culling strategy (C-SSI)] of genotypes was introduced for stability. In the C-SSI method, the top ten genotypes were above-average yielders, while those with below-average yield were observed in NP-SSI and P-SSI methods. Similarly, the estimation of best linear unbiased prediction (BLUP)-based simultaneous selections, such as harmonic mean of genotypic values (HMGV), relative performance of genotypic values (RPGV), and harmonic mean of relative performance of genotypic values (HMRPGV), revealed that none of the top ten entries had below-average yield. The study has proven that C-SSI and BLUP-based methods were equally worthy in the selection of high-yielding genotypes with stable performance. However, the C-SSI approach could be the best method to ensure that genotypes with a considerable amount of stability are selected. The multi-year trial SSI revealed that entries Indaf-9, Sri Chaitanya, PR-202, and A-404; and VL324 and VL146 were ascertained to be the most stable high-yielding genotypes among medium-to-late and early maturity groups, respectively.

Adaptabilidade e estabilidade de berinjela submetida a diferentes níveis de sombreamento via REML/BLUP

ABSTRACT This study aimed to evaluate the eggplant genotype x environment ineraction, using the REML/BLUP procedure, in order to identify genotypes with high productivity, adaptability and phenotypic stability. The experiments were carried out in agricultural greenhouses, in two seasons, with three types of shading: uncovered (UC); covered with plastic diffuser film (PD), 130 microns thick, covered with plastic diffuser film (130 micron) + 50% shading screen (SS). Twelve eggplant genotypes were evaluated, with four replicates and an experimental plot consisting of four plants. The traits evaluated in this study were: fruit set index, number of fruits per plant, average production of fruits/plant and in vitro pollen viability. To assess the adaptability and stability of the genotypes, statistical analyzes and estimation of genetic parameters were performed using the mixed-models of REML/BLUP type, with the aid of SELEGEN software and the statistical model 51. According to the results obtained, the authors verified an agreement between the three methods: Relative Performance of Genetic Values (PRVG), Harmonic Average of Genotypic Values (MHVG) and Harmonic Mean of Relative Performance of Genetic Values (MHPRVG) for average fruits production per plant (PP), number of fruits per plant (NF) and in vitro pollen viability (IVPV), showing the high degree of agreement in the ordering of materials. Thus, it is possible to indicate that the genotypes with the best productive performance, adaptability and stability in the evaluated environments were CNPH135×CNPH60, CNPH135×CNPH51, CNPH135×CNPH141, CNPH109, CNPH109×CNPH60 and CNPH109×CNPH141.

Introgression of Maize Diversity for Drought Tolerance: Subtropical Maize Landraces as Source of New Positive Variants.

Current climate change models predict an increased frequency and intensity of drought for much of the developing world within the next 30 years. These events will negatively affect maize yields, potentially leading to economic and social instability in many smallholder farming communities. Knowledge about the genetic resources available for traits related to drought tolerance has great importance in developing breeding program strategies. The aim of this research was to study a maize landrace introgression panel to identify chromosomal regions associated with a drought tolerance index. For that, we performed Genome-Wide Association Study (GWAS) on 1326 landrace progenies developed by the CIMMYT Genetic Resources Program, originating from 20 landraces populations collected in arid regions. Phenotypic data were obtained from early testcross trials conducted in three sites and two contrasting irrigation environments, full irrigation (well-watered) and reduced irrigation (drought). The populations were genotyped using the DArTSeq® platform, and a final set of 5,695 SNPs markers was used. The genotypic values were estimated using spatial adjustment in a two-stage analysis. First, we performed the individual analysis for each site/irrigation treatment combination. The best linear unbiased estimates (BLUEs) were used to calculate the Harmonic Mean of Relative Performance (HMRP) as a drought tolerance index for each testcross. The second stage was a joint analysis, which was performed using the HMRP to obtain the best linear unbiased predictions (BLUPs) of the index for each genotype. Then, GWAS was performed to determine the marker-index associations and the marker-Grain Yield (GY) associations for the two irrigation treatments. We detected two significant markers associated with the drought-tolerance index, four associated with GY in drought condition, and other four associated with GY in irrigated conditions each. Although each of these markers explained less than 0.1% of the phenotypic variation for the index and GY, we found two genes likely related to the plant response to drought stress. For these markers, alleles from landraces provide a slightly higher yield under drought conditions. Our results indicate that the positive diversity delivered by landraces are still present on the backcrosses and this is a potential breeding strategy for improving maize for drought tolerance and for trait introgression bringing new superior allelic diversity from landraces to breeding populations.

Malt Barley Genotypes Assessed by Analytic Adaptability Measures for NWPZ of the Country

Highly significant effects of the environment (E), genotypes (G), and GxE interaction had been observed by AMMI analysis. Environment explained 51.4% whereas GxE interaction accounted for 22.1% of treatment variations in yield during first year. Harmonic Mean of Genotypic Values (HMGV) expressed higher values for DWRB160, DWRB184, and BH902. Ranking of genotype as per IPCA-1 were BH902, DWRB182, DWRB101. While IPCA-2, selected DWRB101, DWRB123, DWRB184 genotypes. Values of ASV1 selected DWRB101, DWRB182, BH902 and ASV identified DWRB101, DWRB123, DWRB182 barley genotypes. Adaptability measures Harmonic Mean of Relative Performance of Genotypic Values (HMPRVG) and Relative Performance of Genotypic Values (RPGV) identified DWRB160, DWRB184, and BH902 as the genotypes of performance among the locations. Biplot graphical analysis exhibited adaptability measures PRVG, HMPRVG along with IPC3, mean, GM, HM grouped in a cluster. During 2019-20 cropping season Environment effects accounted 79.7% whereas GxE interaction contributed for 7.7% % of treatment variations in yield. HMGV expressed higher values for DWRB196, DWRB123, and RD2849. IPCA-1 scores, desired ranking of genotypes was DWRB182, PL908, RD2849. While IPCA-2 pointed towards PL908, RD2849, DWRB196, as genotypes of choice. Analytic measures ASV and ASV1 selected PL908, RD2849, DWRB123 barley genotypes. HMRPGV along with PRVG settled for DWRB196, DWRB123, and RD2849. Adaptability measures PRVG, HMPRVG clustered with mean, GM, HM and observed in different quadrant of biplot analysis.

Genotype-environment interaction in Cordia trichotoma (Vell.) Arráb. Ex Steud. progenies in two different soil conditions

Investment in silvicultural techniques is noticeably lacking, especially in breeding programs for non-conventional wood species. Studying genotype × environment interaction (G × E) is essential to the development of breeding programs. Thus, this study aimed to estimate genetic diversity of and the effects of G × E interaction on two progeny tests of Cordia trichotoma, including the estimation of genetic gain and genetic diversity after selection. For the experiment, 30 progenies of C. trichotoma were tested at two sites with differing soil textures. Diameter at breast height (1.30 m above soil surface, dbh-cm), total height, diameter at 30 cm from the soil, first branch height, and survival were all monitored for four years. Statistical deviance, best linear unbiased estimator, and harmonic mean of relative performance of genetic values (MHPRVG) were all calculated to predict breeding values, estimate genetic parameters, and analyze deviance. All quantified traits varied significantly among progenies by soil type, with greatest variation recorded for genetic variability. Heritability of the progenies led to predictions of genetic gain, ranging from 7.73 to 15.45%, for dbh at four years of age. The calculated decrease in genetic diversity after selection showed that this parameter should be monitored in subsequent breeding cycles. G × E was low for all tests. The best-performing progenies proved most stable and best adapted to the different environmental conditions tested.

Multi-environmental evaluation of winter oilseed rape genotypic performance using mixed models

The production of winter oilseed rape (WOSR) (Brassica napus) together with increasing seed yields per hectare is one of the strategies for breeding the genetic base of oilseed rape genotypes adapted to different environments. The main objective of this study was to evaluate the genotypic performance of 25 winter oilseed rape genotypes using mixed models. The plant material was examined in five locations in Poland. Field trials were carried out in a randomized complete block design with four replicates. The REML/BLUP was used to estimate genetic parameters. Selection of genotypes was made on the basis of genetic values by the harmonic mean of relative performance these parameters. The mean heritability for genotype had an average value at a high accuracy of selection, while additionally it facilitated selection of agronomically superior individuals. Three restorer lines PN18, PN17 and PN21, CMS ogura line PN64 as well as hybrids PN66 × PN21 and PN64 × PN21 characterized good adaptability and stability of seed yield. There were similarities among the statistics (hat{mu } + hat{g}), adaptability and stability of genetic values in the discrimination of the most productive genotypes by best linear unbiased predictor analysis. Mixed models can be recommended as a potential selection method for the inclusion of new plant material in different oilseed rape breeding programs aimed at developing new WOSR cultivars.

Models for optimizing selection based on adaptability and stability of cotton genotypes

ABSTRACT: In multi-environment trials (MET), large networks are assessed for results improvement. However, genotype by environment interaction plays an important role in the selection of the most adaptable and stable genotypes in MET framework. In this study, we tested different residual variances and measure the selection gain of cotton genotypes accounting for adaptability and stability, simultaneously. Twelve genotypes of cotton were bred in 10 environments, and fiber length (FL), fiber strength (FS), micronaire (MIC), and fiber yield (FY) were determined. Model selection for different residual variance structures (homogeneous and heterogeneous) was tested using the Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC). The variance components were estimated through restricted maximum likelihood and genotypic values were predicted through best linear unbiased prediction. The harmonic mean of relative performance of genetic values (HMRPGV) were applied for simultaneous selection for adaptability, stability, and yield. According to BIC heterogeneous residual variance was the best model fit for FY, whereas homogeneous residual variance was the best model fit for FL, FS, and MIC traits. The selective accuracy was high, indicating reliability of the prediction. The HMRPGV was capable to select for stability, adaptability and yield simultaneously, with remarkable selection gain for each trait.

Estimation of genetic parameters and selection of Coffea canephora progenies evaluated in Brazilian Western Amazon

Coffee has emerged as an economic alternative culture in the State of Acre, Brazil, but without a clonal variety recommended for the state to overcome the unevenness presented by seed crops. Thus, in order to estimate genetic parameters and indicate progenies of Coffea canephora to compose a clonal variety for the State of Acre, yield, vegetative vigor and plant height were evaluated in five harvests of a randomized complete block experiment with 46 progenies, 4 repetitions and 10 plants per plot by mixed model methodology (REML/BLUP). The harvests were evaluated individually, by the model that considers one harvest, one location and the mean of progenies, and joint analysis (all harvests), by repeatability model with stability and temporal adaptability by the harmonic mean of relative performance of genotypic values method (MHPRVG), with genotypic values of progenies grouped by the Tocher method. There was variability, with possibility of selection, only for grain yield. The yield was strongly affected by production bienniality, with high environmental influence and harvests mean ranging from 14.13±4.60 to 46.20±14.94 bags ha-1 and individual heritabilities from 0.10 to 0.44. Sixteen ‘Conilon’ coffee progenies with selection gains above 23% were selected. The MHPRVG method allows the refinement of progeny selection throughout the harvests, identifying the most adapted and stable. Key words: ‘Conilon’ or ‘Kouilou’ coffee; Breeding; Mixed models.

Selection and recommend of quinoa (Chenopodium quinoa) genotypes based on the yield genotypic adaptability and stability

ABSTRACT The present study aimed to select and recommend quinoa genotypes based on the yield genotypic adaptability and stability, by the method of the Harmonic mean of relative performance of genotypic values. Five experiments were conducted during the crop seasons of 2014 and 2015 in two locations in the Western region of Parana State, Brazil. This study involved the evaluation of the yield of thirteen quinoa genotypes. Initially, the genotypic values (GV) were obtained by employing BLUP/REML methodology for mixed models. After, the values of the harmonic mean for genotypic value (HMGV*MG), the relative performance for genotypic values (RPGV*MG) and the harmonic mean of the relative performance for genotypic values (HMRPGV*MG) were obtained. The genotypes Q1317 and Q2014 were the best indicated for cultivation in the summer crop, with medium yield genotypic stability and adaptability. The genotype Q1318 is recommended for winter crop, presenting high yield genotypic stability and adaptability.

Assessing the genotypic performance of carioca beans through mixed models

ABSTRACT: Using genotypes adapted to different regions is one of the main ways to increase Brazilian bean yield. The aim of the present study was to assess the genotypic performance of Carioca beans through mixed models. Fourteen Carioca bean genotypes were assessed in four locations in Pernambuco State (Arcoverde, Caruaru, Belém de São Francisco and São João counties) in 2015. The experiments followed a completely randomized block design, with three repetitions. Genetic parameters were estimated according to the REML/BLUP methodology, whereas genotype selection was based on the harmonic mean of relative performance of genetic values method (MHPRVG). The mean genotype heritability had moderate magnitude, high selective accuracy, besides allowing selection of agronomically superior individuals. Genotypes ‘BRS Notável’, CNFC 15480 and ‘IPR 139’ showed good adaptability and grain yield stability. There was agreement among the statistics μ ̂ + g ̂…, stability (MHVG), adaptability (PRVG), and stability and adaptability of genetic values (MHPRVG) in the discrimination of the most productive genotypes, which presented high adaptability and stability. This outcome indicated that these genotypes can be part of the selection criteria regularly used in bean breeding programs.

Accuracy and simultaneous selection gains for N-stress tolerance and N-use efficiency in maize tropical lines

Maize plants can be N-use efficient or N-stress tolerant. The first have high yields in favorable environments but is drastically affected under stress conditions; whereas the second show satisfactory yields in stressful environments but only moderate ones under optimal conditions. In this context, our aim was to assess the possibility of selecting tropical maize lines that are simultaneously N-stress tolerant and N-use efficient and check for differences between simultaneous selection statistical methods. Sixty-four tropical maize lines were evaluated for Nitrogen Agronomic Efficiency (NAE) and Low Nitrogen Tolerance (LNTI) response indices and two per se selection indices, Low Nitrogen Agronomic Efficiency (LNAE) and Harmonic Mean of Relative Performance (HMRP). We performed eight selection scenarios: LNAE; HMRP; Additive index; Mulamba-Mock index; and Independent culling levels. The last three was predicted by REML/BLUP single-trait and multi-trait using genotypic values of NAE and LNTI. The REML/BLUP multi-trait analysis was superior to the single-trait analysis due to high unfavorable correlation between NAE and LNTI. However, the accuracy and genotypic determination coefficient of NAE and LNTI were too low. Thus, neither single- nor multi-trait analysis achieved a good result for simultaneous selection nor N-use efficiency nor N-stress tolerance. LNAE obtained satisfactorily accurate values and genotypic determination coefficient, but its performance in selection gain was worse than HMRP, particularly in terms of N-use efficiency. Therefore, because of the superior performance in accuracy, genotypic determination coefficient and selection, HMRP was considered the best simultaneous selection methodology of the scenarios tested for N-use efficiency and N-stress tolerance.

Yield adaptability and stability of semi-erect cowpea genotypes in the Northeast region of Brazil by REML/BLUP

ABSTRACT Cowpea is grown in different environmental conditions of the Northeast region of Brazil. Thus, selecting and developing cultivars with high yield, stability, and adaptability for this region is necessary due to the genotype × environment interaction. The objective of this work was to select cowpea lines of semi-prostrate plant simultaneously for high yield, adaptability, and genotypic stability in the Northeast region of Brazil by the REML/BLUP procedure. Twenty semi-prostrate genotypes-16 lines and four cultivars-were evaluated in 36 environments of the Northeast region from 2013-2015. The experiments were carried out under rainfed conditions in a completely randomized block design with four replications. The adaptability and genotypic stability were evaluated by the REML/BLUP procedure. The genotype × environment interaction was complex-type, with the grain yield ranging from 260 kg ha-1 (Campo Grande do Piaui PI, 2015) to 2,764 kg ha-1 (Araripina PE, 2015), with overall mean of 1,304 kg ha-1. According to the Harmonic Mean of Relative Performance of Genetic Values (HMRPGV) estimates, the cultivars BRS Marataoa and BRS Pajeu and the line MNC04-792F-129 had simultaneously high yield, adaptability, and genotypic stability, and can be recommended and grown with greater probability of success in all the environments of the Northeast region of Brazil.

Genotype x environment interaction in cowpea by mixed models

Several methods have been proposed to measure effects of genotype × environment interaction (G×E) on various traits of interest of plant species, such as grain yield. Among these methods, mixed models using the Restricted Maximum Likelihood (REML)-Best Linear Unbiased Prediction (BLUP) procedure with random genotype effects have been reported as advantageous, since they allow the obtaining of actual genotypic values for cultivation and use. The objective of this work was to evaluate the response of grain yield to different locations and years, and the effects of G×E on the performance of cowpea genotypes by the methodology of mixed models. Twenty genotypes were evaluated under rainfed conditions in 47 locations in 2010, 2011 and 2012 using randomized block design. After joint analysis, the genotypes adaptability and stability patterns within and between years were tested by the Harmonic Mean of Relative Performance of Genetic Values (HMRPGV) statistics. The analysis within the years showed highly significant effects of the genotype × location interaction in all the years evaluated. The results of the joint analysis presented highly significant effects (p≤0.01) of the genotype, and triple interaction (genotype × location × year) (p≤0.001), denoting a strong effect of the G×E on the genotype performances. The HMRPGV analysis was adequate to identify superior genotypes, highlighting the MNC02-676F-3, MNC03-737F-5-1, MNC03-737F-5-9, BRS-Tumucumaque, and BRS-Guariba as the genotypes with best stability and highest grain yield. The selection of these genotypes resulted in a new average yield (1,402 kg ha-1) which is higher than that obtained by selection based only on the phenotype (1,230 kg ha-1).

Genetic evaluation of grain sorghum hybrids in Brazilian environments using the REML/BLUP procedure

When it comes to recommending sorghum (Sorghum bicolor) cultivars, it is essential to carry out a genetic evaluation of the agronomic traits of promising genotypes from several common environments where the crop is cultivated. This study consisted of a genetic evaluation of 52 experimental grain sorghum hybrids and eight commercial cultivars. Hybrids were evaluated in 19 experiments representing the most varied cultivation conditions in Brazil. Traits of agronomic interest such as grain yield, flowering and plant height were analysed. Genotypic evaluation was performed following the REML/BLUP (Restricted Maximum Likelihood/Best Linear Unbiased Predictor) procedure; the MHPRVG (Harmonic Mean of Relative Performance of Genotypic Values) method was also employed to study stability and adaptability. Hybrids which stood out in terms of highest grain yield based on genotypic values, stability and adaptability were 0306037, 1G150, DKB 599, 0306039, 1G282 and 0307671. Of these, only 1G282 showed restrictions as to plant height. For flowering, experimental hybrids showed shorter cycles than commercial cultivars, confirming the efficiency of genetic improvement for this trait. With the analysis of grain yield considering days to flowering and plant height as covariates, it was observed that most of the hybrids of greater performance, showed grain yield to be positively influenced by plant height and days to flowering.

Relationships between methods of variety adaptability and stability in sugarcane.

The identification and recommendation of superior genotypes is crucial for the growth of industrial crops, and sugarcane breeding performs a vital role by developing more productive cultivars. The study of genotype x environment interaction has been an essential tool in this process. Thereby, the purpose of this study was to investigate the relationship between methods of adaptability and stability in sugarcane. Data were collected from trials using a randomized block design with three repetitions and 15 clones of sugarcane in nine environments in the State of Minas Gerais, Brazil. Methodologies based on analysis of variance, linear regression, multivariate analysis, nonparametric statistics, and mixed model were used. The methods of Lin and Binns, Annicchiarico, and harmonic mean of relative performance of genotypic values (MHPRVG) were similar in their classification of genotypes. The additive main effect and multiplicative interactions (AMMI) and Wricke methods tended to select the most stable genotypes; however, genotypes were less productive, coinciding with the stability parameter of Eberhart and Russell. The MHPRVG method is preferred over the methods of Lin and Binns and Annicchiarico because it includes the concepts of productivity, adaptability, and stability, and it provide direct genetic values of individuals. The use of the MHPRVG and Eberhart and Russell methods is recommended because the combination of these methods is complementary and leads to greater accuracy in the identification of genotypes of sugarcane for different environments.

Upland rice breeding in Brazil: a simultaneous genotypic evaluation of stability, adaptability and grain yield

The relative performance of one genotype is not identical in different environments due to genotype-environment interaction (G×E). Thus, for a breeding program to successfully develop cultivars, it is fundamental that candidate elite-lines are tested in several target environments and that the data are analysed for yield, adaptability and stability. The objective of this work was to study the G×E for upland rice using a mixed model and, using the harmonic mean of relative performance of genotypic values (HMRPGV) method, to analyse cultivars and elite-lines over time to identify those that aggregate high grain yield (GY) with high genotypic adaptability and stability. A large dataset of “value for cultivation and use trials” collected by the Brazilian Agricultural Research Corporation (Embrapa) and collaborators from 1984 to 2010, involving seven states that represent upland rice crops in the Midwest, North and Northeast regions of Brazil, was used. The effect of location was shown to be more important than the effect of year for promoting crossover interaction. The CNA 8555 had the best GY associated with adaptability and stability, presenting a superiority of 13.28 % above the general mean of all elite-lines. Using already-released cultivars and potential elite-lines, the generalised linear regression analysis revealed significant progress of the stability and adaptability associated with GY over time. The HMRPGV method was shown to be an important tool and allowed identification of three elite-lines in the Embrapa pipeline (AB 062008, AB 062041 and AB 062037), each with high stability, adaptability and yield potential to be released commercially.

AVALIAÇÃO DA INTERAÇÃO GENÓTIPO X AMBIENTE EM CANA-DE-AÇÚCAR VIA MODELOS MISTOS

The objective of this study was to evaluate yield, adaptability, and stability of sugarcane genotypes using the harmonic mean of relative performance of genotypic values method (MHPRVG), and to compare it with the method of differences of the segmented straight line weighted by the residual coefficient of variation (DRRB-CV), based on the Pi statistic from Linn & Binns. Employing the augmented block design, with five blocks, seventy clones and two checks were evaluated. Two experiments were carried out in each of seven environments in Minas Gerais State. Evaluations were performed in plant and ratoon. Considering the selection for sugar yield, adaptability, and stability, three clones performed better: RB947520, RB957712, and P86-42. The MHPRVG method was highly correlated with the parameters of the DRRB-CV method, and with the genotypic values that took into account the genotype x environment mean interaction. All the correlations between these statistical measurements were greater than 0.90. However, the MHPRVG method has the advantage that the results appear on the same scale of the characters evaluated, which could be directly interpreted as genetic values. Another advantage for clone selection is that this method takes into consideration simultaneously the criteria yield, adaptability, and stability. KEY-WORDS: Mixed models, REML/BLUP, stability, MHPRVG method.