Luiz Paulo de Carvalho

Respostas correlacionadas do algodoeiro com a seleção para a coloração da fibra

(3) Resumo – Os constantes trabalhos de melhoramento com o algodao de fibra branca produziram cultivares superiores com fibra de melhor qualidade tecnologica do que a do algodao de fibra colorida. O objetivo deste trabalho foi avaliar o efeito da selecao para diferentes graus de coloracao, nas caracteristicas tecnologicas de fibra do algodoeiro herbaceo em progenies F5 do cruzamento de cultivares adaptadas, de fibra branca, com materiais introduzidos, portadores de genes conhecidos para cor marrom e verde. A maioria dos caracteres de fibra se correlacionou negativamente com a coloracao da fibra, e as respostas correlacionadas diminuiram a medida que se intensificou a selecao para cores mais escuras da fibra. Termos para indexacao: Gossypium hirsutum, progenie, cor, melhoramento de planta. Correlated responses on cotton fiber traits with the selection for fiber color

Biplot analysis of phenotypic stability in upland cotton genotypes in Mato Grosso.

Seed cotton yield is a trait governed by multiple genes that cause changes in the performance of genotypes depending on the cultivation environment. Breeding programs examine the genotype x environment interaction (GE) using precise statistical methods, such as AMMI (additive main effects and multiplicative interaction) and GGE biplot (genotype main effects + genotype x environment interaction). The AMMI method combines the analysis of variance and principal components, to adjust the main effects (genotypes and environments) and the effects of GE interaction, respectively. The GGE biplot groups the genotype additive effect together with the multiplicative effect of the GE interaction, and submits both of these to the principal components analysis. The aim of this study was to investigate the association between the AMMI and GGE biplot methods and select cotton genotypes that simultaneously showed high productivity of seed cotton and stability in Mato Grosso environments. Trials were conducted with cotton cultivars in eight environments across Mato Grosso State in the 2008/2009 crop season. The experiment used a randomized block design with 16 genotypes and four replicates per genotype x environment combination. Data for seeds cotton productivity were analyzed by AMMI and GGE biplot methods. Both methods were concordant in the discrimination of environments and genotypes for phenotypic stability. The genotypes BRS ARAÇÁ and LD 05 CV had high seed cotton productivity and phenotypic stability, and could be grown in all environments across Mato Grosso State.

Seleção massal e porcentagem de fibra em cultivar de algodoeiro colorido

Algodoeiros de fibras coloridas apresentam qualidade inferior em relacao aos de fibra branca, alem de menor potencial de rendimento, porque, comparados aos brancos, os coloridos foram pouco explorados em termos de melhoramento genetico. Este trabalho teve como objetivo avaliar o efeito da selecao massal para porcentagem de fibra alta, media e baixa, dentro de uma populacao da cultivar BRS Verde, lancada em 2003. Quinhentas plantas da cultivar BRS Verde foram colhidas ao acaso e estratificadas em quatro classes quanto a porcentagem de fibra. As sementes de cada classe foram misturadas e participaram de um ensaio em blocos ao acaso com quatro tratamentos, mais a populacao original e quatro repeticoes. Ficou evidenciada a eficiencia da selecao massal em alterar a media das populacoes selecionadas e o ganho de selecao foi de 11% quanto a porcentagem de fibra.

Uso da metodologia REML/BLUP para seleção de genótipos de algodoeiro com maior adaptabilidade e estabilidade produtiva

The restricted maximum likelihood/best linear unbiased predictor methodology (REML/BLUP) has been used for the interpretation of genotypic stability and adaptability of crops such as common bean, sugarcane, cashew, eucalyptus and rice, but researches with cotton are still limited. The aim of this work was to select cotton genotypes, via mixed models, which simultaneously meet adaptability and stability and verify if this methodology can be used in genetic improvement programs in cotton. Thirty-six strains were evaluated in three trials located in Apodi, Rio Grande do Norte (2013 and 2014), and Santa Helena, Goias (2013), in a randomized block design with two replications. The genetic parameters were estimated by REML/ BLUP methodology, and the selection was based on the method of the harmonic mean of the relative performance of the genetic values (MHPRVG), with three strategies: selection based on the predicted genetic value, considering the average performance of genotypes in all environments (without interaction effect); performance in each environment (with interaction effect); and simultaneous selection as to cotton yield, stability and adaptability. The CNPA 2012-60 and CNPA 2012-65 genotypes may be grown in environments similar to those tested, since they present high adaptability and productive stability of cotton. There was agreement among the statistics used in discrimination of the most productive genotypes with high adaptability and stability, indicating that they can be part of selective criteria in the routine of cotton breeding programs.

Number of repetitions for evaluating technological traits in cotton genotypes

With the changes in spinning technology, technological cotton traits, such as fiber length, fiber uniformity, fiber strength, fineness, fiber maturity, percentage of fibers, and short fiber index, are of great importance for selecting cotton genotypes. However, for accurate discrimination of genotypes, it is important that these traits are evaluated with the best possible accuracy. The aim of this study was to determine the number of measurements (repetitions) needed to accurately assess technological traits of cotton genotypes. Seven experiments were conducted in four Brazilian States (Ceará, Rio Grande do Norte, Goiás, and Mato Grosso do Sul). We used nine brown and two white colored fiber lines in a randomized block design with four replications. After verifying the assumptions of residual normality and homogeneity of variances, analysis of variance was performed to estimate the repeatability coefficient and calculating the number of repetitions. Trials with four replications were found to be sufficient to identify superior cotton genotypes for all measured traits except short fiber index with a selective accuracy >90% and at least 81% accuracy in predicting their actual value. These results allow more accurate and reliable results in future researches with evaluating technological traits in cotton genotypes.

Correlations and path analysis among agronomic and technological traits of upland cotton.

To date, path analysis has been used with the aim of breeding different cultures. However, for cotton, there have been few studies using this analysis, and all of these have used fiber productivity as the primary dependent variable. Therefore, the aim of the present study was to identify agronomic and technological properties that can be used as criteria for direct and indirect phenotypes in selecting cotton genotypes with better fibers. We evaluated 16 upland cotton genotypes in eight trials conducted during the harvest 2008/2009 in the State of Mato Grosso, using a randomized block design with four replicates. The evaluated traits were: plant height, average boll weight, percentage of fiber, cotton seed yield, fiber length, uniformity of fiber, short fiber index, fiber strength, elongation, maturity of the fibers, micronaire, reflectance, and the degree of yellowing. Phenotypic correlations between the traits and cotton fiber yield (main dependent variable) were unfolded in direct and indirect effects through path analysis. Fiber strength, uniformity of fiber, and reflectance were found to influence fiber length, and therefore, these traits are recommended for both direct and indirect selection of cotton genotypes.

Usefulness of the HMRPGV method for simultaneous selection of upland cotton genotypes with greater fiber length and high yield stability

The harmonic mean of the relative performance of genotypic predicted value (HMRPGV) method has been used to measure the genotypic stability and adaptability of various crops. However, its use in cotton is still restricted. This study aimed to use mixed models to select cotton genotypes that simultaneously result in longer fiber length, higher fiber yield, and phenotypic stability in both of these traits. Eight trials with 16 cotton genotypes were conducted in the 2008/2009 harvest in Mato Grosso State. The experimental design was randomized complete blocks with four replicates of each of the 16 genotypes. In each trial, we evaluated fiber yield and fiber length. The genetic parameters were estimated using the restricted maximum likelihood/best linear unbiased predictor method. Joint selection considering, simultaneously, fiber length, fiber yield, stability, and adaptability is possible with the HMRPGV method. Our results suggested that genotypes CNPA MT 04 2080 and BRS CEDRO may be grown in environments similar to those tested here and may be predicted to result in greater fiber length, fiber yield, adaptability, and phenotypic stability. These genotypes may constitute a promising population base in breeding programs aimed at increasing these trait values.

Plant breeding in the semiarid region of Brazil: examples of success.

The Northeastern region of Brazil comprises the Caatinga biome (900,000 km2) part of which is a semiarid region with rainfed and irrigated production systems. Among the successful breeding programs are cashew and cotton. The first led to a substantial increase in nut production in Ceara, Rio Grande do Norte and Piaui and the second bred a naturally colored cotton fiber, now processed in small clothing industries in Paraiba, exporting to 11 countries. In the lower-middle Sao Francisco valley, the previously grown onion was replaced by improved varieties, on 90% of the production area, and by industrial tomato, introduced by research in 1972, which came to be used on more than 80% of the area at the time. The participation of the private sector and continuity of breeding programs were crucial for the success. More examples of success are expected with the establishment of postgraduate courses in Agricultural Sciences in the Semiarid region.

Diallel analysis and inbreeding depression in agronomic and technological traits of cotton genotypes

Bragantia, Campinas, v. 77, n. 4, p.527-535, 2018 ABSTRACT: Cotton provides about 90% of the world textile fiber, and is one of the crops of greater industrial relevance. The objectives of this study were to estimate the inbreeding depression and the genetic effects involved in the control of the agronomic and fiber quality traits in F1 and F2 generations and to identify promising hybrids for obtaining superior cotton genotypes. Two cultivars of upland cotton and two moco (Brazilian endemic) cotton were crossed using a half-diallel scheme. The following traits were evaluated: percentage of fibers and weight of one boll, fiber length, fiber uniformity, short fiber index, fiber strength, and micronaire PLANT BREEDING Article

Genetic diversity among cotton cultivars in two environments in the State of Mato Grosso.

Using commercial cultivars to compose crossing blocks in cotton is a promising strategy, because these materials have desirable agronomic and technological characteristics. The objective of this study was to evaluate the genetic diversity among 16 cotton cultivars cultivated in two environments in the State of Mato Grosso, the largest national producer, using agronomical and technological traits. There was significant effect to cultivars for all traits, while genotype x environment interaction was significant only for average boll weight, short fiber index, and maturity of fibers. Therefore, because of the presence of genotype x environment interaction for three traits, we chose to study genetic diversity among cotton cultivars separately in each environment and investigate the interaction impact on the diversity among genotype pairs. Based on agronomical and technological performance and genetic diversity among cultivars in both environments, the most promising cross involves FM 910 and LD CV 02. We also observed that lint percentage and average boll weight presented a higher discrimination capacity in both environments.