Scielo RSS <![CDATA[Crop Breeding and Applied Biotechnology]]> vol. 17 num. 1 lang. pt <![CDATA[SciELO Logo]]> <![CDATA[Adjusting the Scott-Knott cluster analyses for unbalanced designs]]> Abstract The Scott-Knott cluster analysis is an alternative approach to mean comparisons with high power and no subset overlapping. It is well suited for the statistical challenges in agronomy associated with testing new cultivars, crop treatments, or methods. The original Scott-Knott test was developed to be used under balanced designs; therefore, the loss of a single plot can significantly increase the rate of type I error. In order to avoid type I error inflation from missing plots, we propose an adjustment that maintains power similar to the original test while adding error protection. The proposed adjustment was validated from more than 40 million simulated experiments following the Monte Carlo method. The results indicate a minimal loss of power with a satisfactory type I error control, while keeping the features of the original procedure. A user-friendly SAS macro is provided for this analysis. <![CDATA[Marker-assisted screening of breeding populations of an apomictic grass <em>Cenchrus ciliaris</em> L. segregating for the mode of reproduction]]> Abstract Cenchrus ciliaris L. is an apomictic forage grass grown in pastures and rangelands of the semi-arid tropics. It reproduces predominantly through apomixis; rarely, obligate sexual plants have also been reported. Absence of sexual reproduction limits the possibility of genetic improvement through hybridization. This study reports on hybridization of an obligate sexual, self-incompatible buffelgrass with pollen from apomictic plants towards development of an F2 population segregating for mode of reproduction and use of sequence characterized amplified region (SCAR) markers for screening the population. The segregation ratio of 3:1 (facultative: apomictic) was observed in the F1 generation, whereas it was 1:2:1 (apomictic: facultative: sexual) in the F2 generation. A number of obligate sexual F2 progenies with desirable agronomic traits were obtained. The SCAR markers were able to screen out apomictic plants from sexual ones, but failed to discriminate between facultative and sexual. Marker-assisted screening could be useful for introgression of desirable trait(s) in the apomictic genotype through hybridization. <![CDATA[Morphological and physiological characteristics <em>in vitro</em> anthurium plantlets exposed to silicon]]> Abstract The objective was to evaluate morphological and physiological differences in anthurium plants in vitro, with the use of silicon added to the culture medium. Nodal segments were inoculated in Pierik with different sodium silicate concentrations (0.0, 0.5, 1.0 or 2.0 mg L-1). After 100 days in a growth room, phytotechnical characteristics were evaluated, physiological concentrations of silicon, photosynthetic pigments and microanalysis X-ray. A higher yield of chlorophyll a and b, was observed in plants supplemented with 2.0 mg L-1 of sodium silicate. Anthurium plants showed better growth development with an increase in the number of leaves, dry weight and length of the aereal part in plants supplemented with 0.5 and 2.0 mg L-1 sodium silicate. It was also observed an increase in the number of roots of plants supplemented with 1.0 mg L-1 of sodium silicate. The use of sodium silicate in culture medium improves the quality of plantlets with an increased absorption of nutrients in the plant Anthurium. <![CDATA[Adaptability, stability, and genetic divergence of conilon coffee in Alto Suaçuí, Minas Gerais, Brazil]]> Abstract The objective of this study was to describe the genetic parameters, adaptability, and stability of clones from the Coffea canephora variety ‘Vitória Incaper 8142’, and the genetic divergence between them. Following 12 and 24 months of plant growth, several traits were evaluated, including stem diameter, plant height, canopy diameter, number of plagiotropic branches, and number of nodes per plagiotropic branch. The agronomic performance of four crops was determined using measurements of productivity, yield, percentage of floating grains, and grade of the beans. Variability was observed between the clones for the majority of the traits measured. The clones V7, V10, V12, and V13 were the most stable and displayed the highest degree of adaptation for the studied traits, and thus these clones will be used to establish a base population suited to the growing conditions in Alto Suaçuí, Minas Gerais, Brazil. Additionally, the genetic dissimilarity identified between clones allowed suitable clone combinations to be proposed for use in future crosses. <![CDATA[Environmental stratification in cotton in the presence or absence of genotypes with high ecovalence]]> Abstract Cottonseed yield data of 17 genotypes, of which two genotypes contributed to more than 30% of the total ecovalence, and grown in 23 locations, were used to compare four methods of disjoint environmental stratification: a) environmental index (Ie): favorable or unfavorable environments; b) stratification in partitions that maximize the sum of squares of the genotype x partition interaction [(GP)m]; c) environmental scores of the second principal component of the GGE analysis (PC2-GGE); d) environmental scores of the first principal component of the AMMI analysis (PC1-AMMI). Scenarios were simulated (10,000 simulations per scenario) using combination of nine or 13 environments and 11 genotypes, either including or excluding those with the highest ecovalence values. In all scenarios, the greatest selection gains were obtained via PC2-GGE stratification, and the lowest selection gains were obtained via Ie. The ecovalences of the genotypes influenced the results obtained using the stratification methods. <![CDATA[Reaction of common bean lines to <em>Xanthomonas axonopodis</em> pv. <em>phaseoli</em> and <em>Curtobacterium flaccumfaciens</em> pv<em>. Flaccumfaciens</em>]]> Abstract The aim of this study was to evaluate the resistance of 58 common bean lines against common bacterial blight (Xanthomonas axonopodis pv. phaseoli) and bacterial wilt (Curtobacterium flaccumfaciens pv. flaccumfaciens). The experimental design consisted of completely randomized blocks, with four replications per pathogen. The results were subjected to variance analysis by the F test at 1% probability. Significant differences between the treatments indicated different resistance levels among the lines against both pathogens. According to the Scott-Knott test, six lines were resistant to Xanthomonas axonopodis pv. phaseoli, 14 moderately resistant, and 38 susceptible. To Curtobacterium flaccumfaciens pv. flaccumfaciens, 11 lines were resistant, 26 moderately resistant and 21 susceptible. Among these, the lines Pr10-3-4/1, Pr10-5-2/1 and Pr10-5-2/2 of the black bean group and C10-2-4/2 of the Carioca group were resistant to both major bacterial diseases affecting common bean in Brazil. <![CDATA[Combining ability of sugarcane genotypes based on the selection rates of single cross families]]> Abstract This study evaluated the genetic potential of parents used in sugarcane genetic breeding programs based on the performance of previously conducted single crosses. The average selection rate of each family, predicted using Best Linear Unbiased Prediction (BLUP) procedure, was used as a surrogate to the cross performance in the initial evaluation phase. Data analysis was performed using Griffing’s method IV adapted for the available set of crosses to detail the general combining ability (GCA) and specific combining ability (SCA) effects. Significant GCA effects were detected, which demonstrated the possibility of selecting parents based on this parameter. SCA had a higher coefficient of determination than GCA. In conclusion, the selection rate is an effective indicator for evaluation of the combining ability of parents in the first selection stage of a sugarcane breeding program. <![CDATA[Be-Breeder - an application for analysis of genomic data in plant breeding]]> Abstract Be-Breeder is an application directed toward genetic breeding of plants, developed through the Shiny package of the R software, which allows different phenotype and molecular (marker) analysis to be undertaken. The section for analysis of molecular data of the Be-Breeder application makes it possible to achieve quality control of genotyping data, to obtain genomic kinship matrices, and to analyze genome selection, genome association, and genetic diversity in a simple manner on line. This application is available for use in a network through the site of the Allogamous Plant Breeding Laboratory of ESALQ-USP ( <![CDATA[BRS Kurumi and BRS Capiaçu - New elephant grass cultivars for grazing and cut-and-carry system]]> Abstract Cultivar BRS Kurumi is characterized by short plant height, short internodes, high dry matter production (29.25 t ha-1yr-1), has a high nutritional value and is recommended for the cut-and-carry system or grazing. Cultivar BRS Capiaçu, indicated for silage and the cut-and-carry system, has tall upright growth, high dry matter production (49.75 t ha-1yr-1), good forage quality, is lodging-resistant and suitable for mechanical harvesting. Both cultivars are vegetatively propagated by stem cuttings. <![CDATA[BRS 331 - Early cycle double-haploid wheat cultivar]]> Abstract The wheat cultivar ‘BRS 331’ was developed by Embrapa. It results from an interspecific cross between wheat and maize by double-hapolid method. ‘BRS 331’ shows solid stem in the base of the plant, short leaves and super-early cycle to maturity. It is classified as bread wheat in all of the regions that is recommended in the States of Rio Grande do Sul, Paraná and Santa Catarina, Brazil. <![CDATA[BRS FC402: high-yielding common bean cultivar with carioca grain, resistance to anthracnose and fusarium wilt]]> Abstract - BRS FC402 is a common bean cultivar of the carioca-grain group with commercial grain quality, suitable for cultivation in 21 Brazilian states. Cultivar has a normal cycle (85-94 days), high yield potential (4479 kg ha-1), 10.1% higher mean yield than the controls (2462 kg ha-1) and resistance to fusarium wilt and anthracnose. <![CDATA[BRS AG: first cultivar of irrigated rice used for alcohol production or animal feed]]> Abstract BRS AG is an irrigated rice cultivar developed by Embrapa, recommended for cultivation in the state of Rio Grande do Sul. It is intended for grain alcohol production or animal feed, with average thousand-grain weight of 52g (double of the conventional cultivars) and average yield of 8193 kg ha-1. <![CDATA[BRS Pampeira: new irrigated rice cultivar with high yield potential]]> Abstract BRS Pampeira is a rice cultivar developed by Embrapa, recommended for irrigated cultivation in Brazil. It shows modern architecture, with high tillering and tolerance to lodging. It stands out for its high yield potential, medium cycle and good grain quality. <![CDATA[RB036088 - a sugarcane cultivar for mechanical planting and harvesting]]> Abstract The sugarcane cultivar RB036088 is late-maturing, harvested from September to November in south-central Brazil, and is recommended for soils with medium to high fertility. It stands out with continuously high sugar yield over the harvests, longevity of the ratoon plants, high tillering capacity and can be harvested mechanically. <![CDATA[Image - Rice Grain Scanner: a three-dimensional fully automated assessment of grain size and quality traits]]> Abstract The Image is a scanner developed as a grain classifier for quality control at the rice industry based on Brazilian official norms. It orders the dehulled grains ensuring that each grain would pass individually, in free fall, while the grain is analysed from different sides, covering its whole surface. It ensures a precise three-dimensional measurement of grain size, chalkiness, defects of the grain, milling quality, given out a total of 39 traits/classes/defects/values, which are sent to a excel Microsoft spreadsheet. This is managed through a digital platform, which analysis routine and layout were developed and designed by Selgron and Epagri to fit the needs of research. The scanner and its software reach outputs that enhance rice breeding efficiency for grain quality, performing it faster, precisely and with a high-throughput phenotyping than ever before, especially interesting in very early breeding generations.