Mauricio Ferrari

Partial diallel analysis among maize lines for characteristics related to the tassel and the productivity

Diallel crosses are important to the prediction of the best combinations among different heterotic groups of maize lines. The work objective was to estimate the combining ability among inbred lines from two heterotic groups to predict the best combinations in traits related to tassel and grain yield, conducted in five environments in the southern region. The inbred lines of the two heterotic groups are from the company KSP seeds. The tests were conducted based on crosses with partial diallel, using 15 female parents and male parents 8, 2011/2012 agricultural harvest in five environments in randomized blocks design with three replications. The variables analyzed were tassel length (TL), distance from the last node to the first branch of the tassel (DLN), distance from the flag leaf to the first branch of the tassel (DFL), number of tassel branches (NB), mass thousand grains (MTG) and grains yield (GY). The data were submitted the individual and joint variance analysis, after were realized analyze partial diallel analysis. The additive effects were more important for group II, already to the group I the non-additive effects were more pronounced, for the traits tassel and of yield. The GCA (group I) of lines inbred 15; 4 and 3-4 (group II) are favorable for increasing the grains yield. The crosses promising tassel traits been: 1-3, 2-4, 3-3, 4-4, 7-3, 8-3, 9-3, 10-3, 10-4, 11-4, 12-4, 14-3 and 15-4. The crosses promising increasing of grains yield been: 1-1, 1-4, 2-3, 3-1, 3-4, 4-3, 4-6, 4-7, 5-3, 5-4, 6-3, 6-4, 7-4, 8-4, 9-4, 10-5, 11-3, 12-3, 14-4, 15-2, 15-5 e 15-8. Key words: Combinatorial capacity, genic effect, diallel crosses, grain yield.

Estimates of genetic parameters and genotypic values prediction in maize landrace populations by REML/BLUP procedure

The REML/BLUP statistics are analyses that can be used as selective criteria in the routine of maize breeding programs. The present study aims to determine the genetic potential in crosses of landrace populations applying the REML/BLUP methodology, and to identify populations for the synthesis of new populations and intrapopulation selection for family farming systems, as well as genetic constitutions for use in maize breeding programs. Nine top cross hybrids obtained in the 2012/2013 harvest were evaluated along with their testator, the landraces used as parents, and four commercial hybrids, in a randomized block design, with information taken from the average of each plot. The evaluated traits were: leaf angle, number of ramifications of the tassel, spike insertion height, plant height, spike diameter, number of grains per spike, mass of grains per spike, spike mass, spike length, prolificity, mass of one hundred grains, and grain yield per plot. The data were analyzed using the Selegen-REML/BLUP software. The top cross hybrids Cateto Branco x Planalto, Amarelão x Planalto and the population Cateto Branco are ranked among the ten best crosses, simultaneously, for the traits: leaf angle, number of ramifications of the tassel, spike insertion height, and plant height (Cateto Branco x Planalto), and leaf angle, spike insertion height, and plant height (Amarelão x Planalto and Cateto Branco). The top cross hybrids Criolão x Planalto, Branco 8 Carreiras x Planalto, Caiano Rajado x Planalto, Amarelão x Planalto, Branco Roxo Índio x Planalto stand out for their high genotypic value of the individual BLUP mean components among the ten best genotypes for grain yield, and by combining three or more traits of interest together, being, for effects of selection, the most indicated.

REML/BLUP and sequential path analysis in estimating genotypic values and interrelationships among simple maize grain yield-related traits

Methodologies using restricted maximum likelihood/best linear unbiased prediction (REML/BLUP) in combination with sequential path analysis in maize are still limited in the literature. Therefore, the aims of this study were: i) to use REML/BLUP-based procedures in order to estimate variance components, genetic parameters, and genotypic values of simple maize hybrids, and ii) to fit stepwise regressions considering genotypic values to form a path diagram with multi-order predictors and minimum multicollinearity that explains the relationships of cause and effect among grain yield-related traits. Fifteen commercial simple maize hybrids were evaluated in multi-environment trials in a randomized complete block design with four replications. The environmental variance (78.80%) and genotype-vs-environment variance (20.83%) accounted for more than 99% of the phenotypic variance of grain yield, which difficult the direct selection of breeders for this trait. The sequential path analysis model allowed the selection of traits with high explanatory power and minimum multicollinearity, resulting in models with elevated fit (R2 > 0.9 and ε < 0.3). The number of kernels per ear (NKE) and thousand-kernel weight (TKW) are the traits with the largest direct effects on grain yield (r = 0.66 and 0.73, respectively). The high accuracy of selection (0.86 and 0.89) associated with the high heritability of the average (0.732 and 0.794) for NKE and TKW, respectively, indicated good reliability and prospects of success in the indirect selection of hybrids with high-yield potential through these traits. The negative direct effect of NKE on TKW (r = -0.856), however, must be considered. The joint use of mixed models and sequential path analysis is effective in the evaluation of maize-breeding trials.

Diallel and prediction (REML/BLUP) for yield components in intervarietal maize hybrids

Genetic improvement is essential to achieve increments in maize (Zea mays L.) grain yield components. It may be obtained through crosses, which enable to exploit the effects of intervarietal heterosis, allelic complementarity, as well as gene actions and effects. This study estimated the components of variance and genetic parameters (REML/BLUP) of an intervarietal diallel to select and predict the best genotypes for maize yield components. The experimental design was randomized blocks containing 60 intervarietal maize hybrids arranged in three repetitions. They were obtained through intervarietal crosses and evaluated in a diallel scheme, where 14 open-pollinated varieties were designated as parentals. Thus, 10 crosses were performed for each hybrid combination to obtain the number of seeds necessary for the competition test. The measured traits were: grain volume relative index, the mass of one hundred grains, and grain yield. The male parents and the additive genetic fraction were determinants for grain volume relative index. Mass of one hundred grains and grain yield were defined by the specific combining ability, and female parents revealed low narrow sense heritability. The female parent Taquarão and male parent Argentino Amarelo presented the best general combining abilities for the measured traits. The specific combining abilities were expressed for crosses AL 25 x Dente de Ouro Roxo, AL 25 x BRS Pampeano, and Taquarão x Argentino Branco. Genetic estimates and predictions were consistent and applicable to breeding programs and could be applied in future quantitative genetic studies of maize.

Desempenho fisiológico de sementes olerícolas em diferentes tempos de hidrocondicionamento

The production of high quality physiological seed is a major challenge for seed producers. In the search for lower cost conditioners arises the possibility of using hydropriming, which consists of a controlled hydration of seeds. The aim of this study was to evaluate the efficiency of this technique on lettuce, cabbage and tomato seeds, submitted to different times of imbibition in water. Eight periods of hydropriming in three vegetable crops were used, wherein for each of these was conducted a separate experiment. For lettuce and cabbage, periods tested were 0, 5, 10, 15, 20, 25, 30 and 35 hours and for tomato were of the periods 0, 24, 48, 72, 96, 120, 144 and 168 hours. The seeds of each treatment were submitted to the germination test and vigor to determine the physiological potential. For the tomato crop, the best answers to the average time of germination, emergence speed index and emergency field were found 72 hours of imbibition. As for the cabbage crop the best answers to these variables were obtained with 20 hours of imbibition. Lettuce did not respond positively to the imbibition times.

Parcelamento e fontes de nitrogênio na qualidade fisiológica de sementes de trigo

Diferentes fontes e manejos parcelados de nitrogenio podem aumentar a disponibilidade, a absorcao e a assimilacao deste nutriente pelas plantas, favorecendo o acumulo de N nos graos. No entanto, pouco se sabe sobre a influencia destes fatores na qualidade fisiologica de sementes de trigo (Triticum aestivum L). Dentro deste contexto, o objetivo deste trabalho foi avaliar a resposta de diferentes fontes e parcelamentos de nitrogenio aplicado em cobertura na qualidade fisiologica das sementes de trigo. O experimento foi conduzido em delineamento de blocos completos casualizados em esquema de parcelas subdivididas com tres cultivares de trigo (TBIO Mestre, TBIO Iguacu e Quartzo), tres fontes de nitrogenio (ureia, nitrato de amonio e ureia liquida) aplicadas em cinco parcelamentos (I: afilhamento; II: afilhamento e emborrachamento; III: afilhamento e florescimento; IV: emborrachamento e florescimento e V: afilhamento, emborrachamento e florescimento). O parcelamento do nitrogenio entre os estadios de emborrachamento e florescimento resulta em sementes com maior qualidade fisiologica, pois incrementa o percentual de germinacao em 4% e influencia positivamente os caracteres na primeira contagem de germinacao, comprimento de parte aerea, e massa seca de plântula. As fontes de nitrogenio, nitrato de amonia e a ureia fonte liquida, se equiparam com a ureia em relacao ao efeito na qualidade fisiologica das sementes, sendo alternativas interessantes para reduzir o custo de producao. As cultivares TBIO Mestre e Quartzo evidenciaram sementes com maior qualidade fisiologica, em funcao do maior comprimento de radicula e percentual de germinacao.

Indução de mutação e mensuração da variabilidade genética em genótipos de cana-de-açúcar

The widespread usage of commercial varieties of sugar that are adapted to the agricultural system and come from parents with a small genetic distance can lead to a narrowing of the genetic basis of sugarcane. This study aimed to induce mutations and evaluate the genetic distance among the sugarcane mutants produced by different multivariate techniques. Mutations were induced and then the genetic distance among these sugarcane mutants was evaluated with the use of multivariate techniques. The study was conducted in the experimental area of the UFSM, Frederico Westphalen, RS. The genotype used for mutation induction was IAC 873396. The induction process proceeded with the placement of buds in a solution of the mutagenic agent MMS (Methyl Methane Sulfonate). A total of 22 mutations and six commercial checks were evaluated for 12 traits of agronomic interest. The analyses were: the evaluation of individual averages, Tocher’s grouping, average Euclidean distance, an analysis of principal components, and the relative contribution of characteristics. The mutation induction process generated significant patterns of genetic variability among sugarcane mutants verified by three multivariate analyses. The UPGMA clustering methods, Tocher and principal component analysis revealed similar results related to the dissimilarity of sugarcane genotypes. Genotypes 20, 24, and 10 were greater than the general average of genotypes and have a high genetic dissimilarity for traits. The yield of stems, bagasse mass, and the yield sugarcane broth are sufficient to characterize a set of sugarcane genotypes.

Adaptability, Stability and Multivariate Selection by Mixed Models

The aim of this work was to estimate the adaptability and stability of grain yield per hectare and percentage of crude protein of maize grains combined in an index, and to establish a multicharacter selection through mixed models based on an objective character and 15 auxiliary traits. The trials were conducted in the 2013/2014 agricultural year in four growing environments of the Rio Grande do Sul, BR state. The experimental design was randomized blocks arranged in a factorial scheme, being four growing sites × 15 single cross maize hybrids, arranged in three repetitions. The genotypic index, composed by the grain yield and the crude protein percentage in the grains, is the best selection strategy to achieve maize superior genotypes. The multivariate genotypes selection, considering grain yield and crude protein, is efficient. The genotypes FORMULA TL®, AS1656PRO®, P30F53Hx®, LG6304YG® and 30F53 are more adapted and stable for grain yield and percentage of crude protein, in the conditions of this study. The mixed models were efficient to employ the multicharacter selection and to contribute for maize genetic breeding.

Efeitos na produção e constituição bromatológica de silagem de híbridos de milho em diferentes ambientes

The aim of this study was to assess silage corn hybrids morphological, productive and bromatological parameters in irrigated and non-irrigated environmental conditions. The research was held in the 2010/2011 season, Campos Borges – RS. The experimental design was randomized blocks in factorial design, with two environments x eight corn hybrids, arranged in three replications. Analysis of variance showed environment x corn hybrids interaction significance for plant height, fresh and dry matter per hectare, dry matter percentage, mineral matter, crude protein, neutral detergent fiber, lignin, total and non-fibrous carbohydrates. In the irrigated environment, hybrids showed higher plant height, chlorophyll content, leaf area, fresh and dry matter per hectare, silage dry matter percentage, pH, mineral material, neutral detergent fiber, cellulose and lignin. Non-fibrous and total carbohydrate levels were higher for the non-irrigated environment. Crude protein content was higher in the non-irrigated environment. In the irrigated environment HS1356 hybrid showed higher plant height, fresh and dry matter per hectare, mineral material and neutral detergent fiber. HT4 hybrid led to higher silage crude protein content in the irrigated environment.

Efeitos de enxofre e nitrogênio na qualidade industrial e no rendimento de grãos de trigo

The consumer market’s demand and requirement for wheat grains which present a satisfactory industrial quality have driven the demand for enhanced cropping systems, especially related to nutritional aspects. In this context, the purpose of this research was to evaluate how the sulfur supplementation and the usage of nitrogen (N) affect the baking quality and the yield of the wheat grain cultivar TBIO Itaipu®. A randomized block experimental design in factorial arrangement, with two sulfur managements (with and without) and four split nitrogen managements (I: 100% of N in the double ring; II: 30% of N in the tillering period + 40% of N in the double ring + 30% of N in the ear development; III: 50% of N in the tillering period + 50% of N in the double ring; IV: 50% of N in the double ring + 50% of N in the ear development period), arranged in four repetitions. Our results showed that the sulfur supplementation increased the gluten content, which has been positively correlated with the strength and extensibility of the bread dough. This had a positive influence on the technological parameters of the flour used for baking. The splitnitrogen fertilizer application (in double ring, tillering, and ear development) increased the wheat grain yield due to the greater number of tillers per plant and also of the wheat ears per square meter.