Scielo RSS <![CDATA[Crop Breeding and Applied Biotechnology]]> vol. 16 num. 1 lang. es <![CDATA[SciELO Logo]]> <![CDATA[Factor analysis applied to the G+GE matrix via REML/BLUP for multi-environment data]]> Abstract The genotype x environment interaction is frequently observed in many crops and studies on environmental stratification and genotype adaptability have been proposed to understand it. The aim of this study was to carry out factor analysis in data from multi-environment experiments by the mixed model approach (REML/BLUP). Instead of adjusted phenotypic means, a matrix containing the genotypic effects added to the effects of the genotype x environment interaction (G+GE) was used, predicted via REML/BLUP in joint analysis (designated as R-FGGE). In the study, data from 36 common bean lines evaluated in 15 environments were used. By this proposal, 46.7% of the environments were gathered in two groups, one with four and the other with three environments. The R-FGGE has the same characteristics as the previous proposals, that is, ease of identification of mega-environments and genotypes with broad adaptability, along with the advantages associated with the mixed model methodology. <![CDATA[Pathogenic variability of <em>Moniliophthora perniciosa</em> in three agroecological zones of the cacao region of Bahia, Brazil]]> Abstract Resistant cacao genotypes are the best measure to control the Witches' broom disease of cacao. To ensure efficiency, the pathogen variability in the cacao region of Bahia must be investigated. The pathogenic variability of Moniliophthora perniciosa inocula from nine municipalities was analyzed: Ilhéus, Floresta Azul and Jussari (agroecological zone Almada); Ipiaú, Itagibá and Jitaúna (agroecological zone Ipiaú), Camacan, Santa Luzia and Pau Brasil (agroecological zone Camacan), by inoculating progenies of Sca 6, ICS 1 and SIC 23 seedlings with 2 x 105 basidiospore.mL-1 of inocula and inoculum mixtures per agroecological zone, in a factorial 3 x 13 design, with 4 replications of 28 plants, in two seasons. Symptoms were assessed 60 days after inoculation. Pathogenic variability of inoculum in relation to the progeny performance was found; Ipiaú was the most aggressive and progeny ICS 1 the most susceptible. The mixtures of the agroecological zones Almada and Ipiaú were contrasting. <![CDATA[Bayesian estimation of genotypic and phenotypic correlations from crop variety trials]]> Abstract Genotypic and phenotypic correlations are necessary for constructing indirect selection indices. Bayesian analysis, therefore, was applied to obtain posterior distributions of the correlations, and the estimates were compared with those under a frequentist approach. Three a priori distributions for standard deviation components based on uniform distribution, positive values from t- distribution, and positive values from normal distribution were examined, while a priori distribution for correlation was taken as a uniform distribution. The prior based on uniform was best found using the deviation information criterion. Data from sorghum genotypes evaluated in complete blocks in 2010-2011 in Northern Kordofan, Sudan, resulted in a posterior mean of 0.48 for genotypic correlation between seed yield and seed weight with posterior standard deviation of 0.24. Due to a wider inference base and the fact that it makes use of prior information, we recommend the Bayesian approach in estimation of genotypic correlations. <![CDATA[Construction and characterization of a bacterial artificial chromosome library of the maize inbred line Qi319]]> Abstract Zea mays L. has been the most cultivated crop and the crop with the largest yield in China since 2012. We constructed a bacterial artificial chromosome (BAC) library for the maize inbred line Qi319, which may be used as a key source for disease-resistant maize breeding in China. The BAC contains 270,720 clones, with an average insert size of 90 kb. The coverage of the library is about 10.43 genome equivalents when considering a haploid genome size of 2300 Mb, providing a 99.99% likelihood of isolating any maize gene or sequence in the library. An average of 12 clones were obtained by polymerase chain reaction screening by using primer pairs linked to the genes for resistance to maize southern rust and rough dwarf. The results indicate that the library can satisfy the requirements for recovering specific sequences. The library is available to researchers to whom it may be of interest. <![CDATA[Molecular characterization of 'sweet' cassavas (<em>Manihot esculenta</em>) from a germplasm bank in Brazilian Eastern Amazonia]]> Abstract Genetic variability of a set of 81 accessions of 'sweet' cassavas (Manihot esculenta) collected mostly in the North region of Brazil was investigated with nine microsatellite loci. All loci were polymorphic, with mean of 6.33 alleles per locus. Analyses indicated that 35 multiloci profiles were represented by a single accession, and 46 showed non-unique profiles, represented by eleven genotypes. Forty-six different multiloci profiles were detected. Most of the putative duplicated accessions were collected in different locations. After the removal of putative duplicated genotypes, genetic parameters were estimated and expected heterozygosity was high (HE=0.73), indicating genetic variability. Structure analysis of this set of 'sweet' cassavas divided the 46 genotypes into two clusters (K=2), and a few genotypes had mixed ancestry. Results indicated the habit of exchange of materials among farmers of the North region of Brazil, and the genetic variability to be exploited in genetic breeding efforts. <![CDATA[Tetraploidization in citrus rootstocks: effect of genetic constitution and environment in chromosome duplication]]> Abstract The objective of this study was to identify polyploid plants from citrus rootstocks and to evaluate the influence of the genetic constitution and of the environment on the frequency of chromosome duplication. Populations obtained from rootstock seeds of Trifoliata [Poncirus trifoliate (L.) Raf], citrumelo 'Swingle' [C. paradise Macf. × P. trifoliate], citrange 'Troyer' [C. sinensis (L.) Osb. x P. trifoliate] and citranges Fepagro 'C13', 'C37' and 'C41' [C. sinensis (L.) Osb. cv. Pêra x P. trifoliata] were evaluated under field and greenhouse conditions. Flow cytometry analysis of 415 field plants and 435 greenhouse plants identified seven (1.69%) and 29 (6.67%) tetraploids, respectively. Differences in the number of tetraploid plants among genotypes and locations were observed in field progenies of 'C 37' (2.12%) and 'C 13' (2.04%) and in greenhouse progenies of 'C 13' (15.52%) and 'C 37' (6%). The frequency of autotetraploidization events in citrus rootstocks is common and appears to be associated to genetic constitution and environmental conditions. <![CDATA[<em>Coffea arabica</em> clones resistant to coffee leaf miner]]> Abstract Brazilian arabica coffee production is based on a set of highly productive cultivars sexually propagated. All of them are susceptible to coffee leaf miner, Leucoptera coffeella, and most of them are also susceptible to coffee leaf rust, Hemileia vastatrix. Aiming to reduce the selection process of cultivars with multiple resistances to both biotic constraints, the Coffea arabica clones 760, 1059, 1064 and 1215 were evaluated under field conditions. The mean yield of four C. arabica clones was not statistically different from the experimental controls; however, the yield of clone 1059 was 21% higher than the control cultivar Obatã IAC 1669-20. Leaf miner resistance level in all the evaluated clones remained the same as the mother plant's. However, the same did not occur for resistance to H. vastatrix, due to the emergence of new pathogen races. In summary, it is potentially feasible the adoption of clone 1059 as a new clonal cultivar resistant to coffee leaf miner. <![CDATA[<em>In vitro</em> callus induction and micropropagation of <em>Thymus persicus</em> (Lamiaceae), an endangered medicinal plant]]> Abstract This is the first attempt towards an efficient regeneration protocol for an endangered and valuable medicinal plant, Thymus persicus using in vitro callus induction and indirect organogenesis. Callus induction was performed on MS medium supplemented with different concentrations of NAA and 2,4-D, alone or in combination with BAP and KN. Maximum callus induction (100%) was achieved from internode explants cultured on MS medium fortified with 2.0 mg L-1 NAA and 0.5 mg L-1 KN. The highest frequency of shoot multiplication (96%) was observed with 2.0 mg L-1 BAP+1.0 mg L-1 NAA. The maximum number of rootlets (16.6 ± 1.4) was induced on half-strength MS medium with 0.5 and 1.0 mg L-1 IBA. Rooted plantlets were then successfully grown and acclimatized in the greenhouse with a 70-85% survival rate. The benefits of the protocol described here include all-year-round application, germplasm conservation, suitability for commercial production and also for the biotechnological production of pentacyclic triterpenoids. <![CDATA[Genetic resistance of maize inbred lines to anthracnose leaf blight]]> Abstract The objectives of this study were to evaluate the resistance of maize inbred lines to anthracnose leaf blight (Colletotrichum graminicola Ces.), and to estimate genetic parameters associated with resistance. Sixteen lines (S5) were evaluated for resistance to anthracnose leaf blight in three experiments, in a randomized block design with four replications. From three evaluations of severity, it was estimated the area under the disease progress curve (AUDPC), and the genetic parameters associated with resistance. Results showed the existence of genetic variability for resistance to anthracnose leaf blight in the set of studied lines. Five lines stood out for the high resistance pattern to anthracnose leaf blight, presenting the lowest AUDPC values in the three experiments, and thus were considered important sources of C. graminicola resistance genes. Estimates of genetic parameters indicated low participation of the environment and highlighted the possibility of genetic gains with artificial selection for resistance in this pathosystem. <![CDATA[Genetics and identification of markers linked to multiflorous spikelet in hexaploid oat]]> Abstract The formation of naked grains is directly associated with the formation of multiflorous spikelets in oats. The objectives of this study were to determine the genetics of multiflorous spikelet and to identify molecular markers linked to this character in hexaploid oat. Genetic analysis for multiflorous spikelet was performed in the F5 and F6 generations of two oat populations. DNA extracted from F5:6 plants were assayed with 6,000 genome-wide single nucleotide polymorphism (SNP) markers using a genotyping platform developed for oat. Genetic analysis indicated the presence of a major gene controlling multiflorous spikelet in the UFRGS 01B7114-1-3 x UFRGS 006013-1 population. The SNP marker GMI_ES17_c5923_221 showed strong association with the multiflorous spikelet phenotype. These results suggest that the marker GMI_ES17_c5923_221 should be linked to a gene controlling multiflorous spikelet in the oat lines evaluated in this study. <![CDATA[BRS 404 - wheat cultivar for rainfed conditions]]> Abstract BRS 404 is a new wheat cultivar developed by Embrapa, indicated for rainfed conditions. It has a particularly good performance under heat and drought conditions. The grain yield is stable and BRS 404 is classified as bread wheat. <![CDATA[CD 1805 - Wheat with flour characteristics for cookie baking]]> Abstract CD 1805, indicated for the wheat growing in Regions 1, 2 and 3 in the states of Rio Grande do Sul, Santa Catarina and Paraná. The cultivar has quality standards for cookie production and high yield performance with a mean of 3899 kg ha-1, exceeding the controls by 4%.