Medfly Phenotypic Plasticity as a Prerequisite for Invasiveness and Adaptation

The hypothesis of this study was that different plant hosts of the medfly Ceratitis capitata may cause variability as a prerequisite for its invasiveness. The main objective was to determine population variability based on medfly wing shape in three favorable medfly host plants (peach, fig and mandarin) from different agroecological growing areas with different pest management practices, and to evaluate phenotypic plasticity as a basis for future expansion into new areas and new hosts. Using geometric morphometric methods across 14 specific landmarks on the medfly wings, 10 populations were tested from infested peach, fig and mandarin fruits, as well as laboratory-grown sterile populations. The studies led to the following main findings: (1) all of the medfly populations that were studied exhibited sexual dimorphism in wing shape; (2) the hosts in which the medfly develops influence wing shape and condition its variability; (3) there is significant variability between laboratory mass-reared sterile and wild individuals in male and female populations; (4) a high phenotypic plasticity of medfly populations was observed along the study sites. Even the low but clearly detected variability between different agroecological conditions and localized variability indicate genotypic stability and high phenotypic plasticity, which can be considered as a prerequisite for medfly invasiveness and dispersal to new areas.

Combined selection for adaptability, genotypic stability and cowpea yield from mixed models

ABSTRACT: The potential expression of crop productivity is a constant challenge for plant breeders in the face of oscillations in environmental variables, making selection difficult and increasing the operational and methodological costs in obtaining the ideal cultivar for a determined region. The objective of the research was to investigate the effects of genotype x environment interaction in the selection of cowpea lines with high grain yield, adaptability, and genotypic stability simultaneously, in environments of the Northwest region of Rio de Janeiro State, using mixed models (Maximum Restricted Likelihood - REML/Best Linear Unbiased Prediction - BLUP). 27 cowpea genotypes were evaluated in six environments by combining location (Cambuci-RJ and Bom Jesus do Itabapoana-RJ) and year (2016, 2017 and 2018). A randomized block design with four replications was performed. The genetic parameters were estimated via the REML/BLUP procedure, and the selection was based on the harmonic mean method of the relative performance of the genetic values (HMRPGV). A meaningful difference was observed for environment and genotype x environment interaction. The residual variance and the variance of the genotype x environment interaction formed the most significant fractions of the phenotypic variance. Lines 4 (Bico-de-ouro 1-5-24), 6 (Pingo-de-Ouro 1-5-4), 5 (Pingo-de-Ouro 1-5-26), and 9 (Pingo-de-Ouro 1-5-8), stood out as superior in terms of stability and adaptability and grain yield by HMRPGV. Commercial cultivars 13 (BRS-Tumucumaque) and 26 (BRS-Itaim) had high grain yield, adaptability, and specific stability in the evaluated edaphoclimatic conditions.

Simultaneous selection of peach rootstocks by mixed models

The term adaptability refers to the ability of a genotype to respond favorably to environmental spur, while stability is the predictability of genotypic behavior. Therefore, the objective was to select Prunus rootstock cultivars with greater adaptability and genotypic stability for subtropical environmental conditions using the HMPRVG method. The experiment was conducted in Chapecó, Santa Catarina State, Brazil. Twenty-one rootstock genotypes were evaluated under the ‘BRS-Libra’ canopy cultivar and one genotype from self-rooted seedlings. The 22 genotypes were evaluated for canopy volume, yield, fruit diameter and fruit set in the growing seasons 2015/16, 2016/17, 2017/18 and 2018/19. Adaptability and stability were measured by means of the harmonic mean relative performance of genotypic values (HMRPGV). In addition, genetic parameters for heritability and ratio test were measured. According to the results, the self-rooted, ‘De Guia’, ‘I-67-52-4’, ‘Mexico Row 1’ and ‘Rosaflor’ genotypes coincided most frequently in the ranking of the three most adaptable and stable genotypes. On the other hand, the ‘P. mandshurica’, ‘Rigitano’ and ‘Santa Rosa’ genotypes corresponded to the lowest adaptability and stability values, thus constituting low quality genetic materials for cultivation. It can be concluded that under the tested conditions the HMPRVG method is efficient for the Prunus rootstock selection cultivars and the ‘BRS-Libra’ grafted on ‘Mexico Row 1’, ‘Rosaflor’ rootstocks and trees from self-rooted seedlings have greater adaptability and phenotypic stability under the subtropical cultivation conditions.

Adaptability and stability of jabuticaba tree genotypes based on plant growth

The aim of this work was to verify by means of adaptability and stability analyses which genotype of Plinia sp. (jabuticaba tree) is more adapted to orchard conditions, based on the measures of stem growth and primary shoots. During a three-year period, the initial growth of jabuticaba tree genotypes from the native fruit collection of the Experimental Station of the Universidade Tecnológica Federal do Paraná - Câmpus Dois Vizinhos was evaluated. These genotypes included seedlings from forest fragments of the southwestern region of Paraná State and some from Minas Gerais State, Brazil. Analysis of variance (ANOVA) was performed, in a 29 x 3 factorial design, with three replicates in each treatment. Phenotypic adaptability and genotypic stability were evaluated based on the data obtained by the following methods: Eberhart and Russell, Lin and Binns and the AMMI. The analyses were carried out through the computer programs GENES and Stability. The methods that were tested to determine the adaptability and stability of the growth behaviour of the jabuticaba tree did not present consistent patterns in the results. However, the genotype generally referred to as 'Vitorino' was the most suitable for open-air cultivation.

Simultaneous selection for yield, adaptability, and genotypic stability in immature cowpea using REML/BLUP

The objective of this work was to select cowpea genotypes simultaneously for high yield of immature grains, adaptability, and genotypic stability, taking into account genotype x environment interactions. The mixed models restricted maximum likelihood (REML)/best linear unbiased prediction (BLUP) were used. Sixteen cowpea genotypes were evaluated in nine environments, consisting of a combination of location (Pentecoste in the state of Ceará, Acaraú in Ceará, Teresina in Piauí, and Mossoró in Rio Grande do Norte, Brazil) and year (2012, 2013, 2014, 2015, and 2017). In all trials, a randomized complete block design with four replicates was used. Significant differences were observed for effects of genotypes and the genotype x environment interaction. Environmental variance was the largest component of phenotypic variance, followed by the genotype x environment interaction and genotypic variances. The immature grain yield of the evaluated cowpea genotypes interacts strongly with the studied environments, resulting in a low genotypic correlation between environments. The MNC00-595F-27, MNC05-847B-123, and BRS Tumucumaque cowpea genotypes present high yield of immature grains, adaptability, and genotypic stability, being the most suitable for cultivation in the states of Ceará, Piauí, and Rio Grande do Norte or in other environments with similar soil and climatic conditions.

AMMI based simultaneous selection for yield and stability of chickpea genotypes in south zone of India

Multi-environmental trials have generally significant genotype main effects and genotype x environment interaction (GEI) effect and, therefore different univariate and multivariate stability methods have been used to study the GEI. Among the multivariate methods, the additive main effects and multiplicative interaction (AMMI) analysis is widely used for GEI investigation. This method has been effective because it captures a large portion of the GEI sum of squares; it clearly separates main and interaction effects and often provides meaningful interpretation of data to support a breeding program such as genotypic stability. Based on the AMMI model, a stability index has been used to rank the genotypes. This index is the weightage of stability and yield component and higher the index value better is the genotypes. The index of 40 promising chickpea genotypes were calculated with two different weight of yield (50% and 75%) and stability component (50% and 25%). These genotypes were evaluated at seven locations viz. Hiriyur, Nandyal, Coimbtore, Dharwad, Lam, Bijapur and Gulbarga representing the south zone of All India Coordinated Research Project on Chickpea program during 2015-16. Ranking of genotypes are done based on two different weight of stability and yield component.