Flávio Jesus Wruck

Genetic progress after cycles of upland rice recurrent selection

Periodic assessment of the genetic progress made in recurrent selection programs is essential for assessing the evolution of the programs and identifying the main factors that have contributed to this progress. This study aimed to estimate genetic progress in grain yield, plant height and days-to-flowering achieved in the CNA6 population of upland rice (Oryza sativa L.), after four cycles of recurrent selection; and evaluate the genetic potential of this population to generate superior inbred lines after each selection cycle. The experimental data were obtained from progeny yield trials of each recurrent selection cycle. These trials were carried out in two or three locations per cycle, and consisted of S0:2 progenies and at least three checks. Federer’s augmented block design, with one replication on location (the environment), was adopted. Results revealed genetic progress for grain yield and plant height, with total genetic gains of 375.87 kg ha−1 and -3.90 cm, respectively, during the four selection cycles. The annual relative gain observed for grain yield was 1.54 %. The genetic potential of the population was analysed by the expected proportion of superior inbred lines. The standard adopted as the limit for obtaining superior inbred lines was the average of the checks for each trait. The genetic potential for grain yield and plant height increased during the study period. For days-to-flowering, no genetic gain occurred; however, the genetic potential of the population to generate superior inbred lines for this trait was maintained after the selection cycles.

Atributos físico-hídricos do solo em sistema integrado de produção com diferentes arranjos do componente florestal paricá

The objective of this work was to compare the structural quality and water retention curve of a Haplustox under single, double, and triple “paricá” (Ochroma pyramidale) lines in an integrated production system at 50 months of implantation. Soil was collected from five sampling points considering the distances from the tree lines. Undisturbed samples were collected from the 0.00–0.10 and 0.10–0.20-m layers in order to assess porosity, density, soil penetration resistance, soil water retention curve, and the “S” index. The forest arrangement based on three paricá lines promoted better soil physical conditions than the system using single lines. The main changes were recorded in the 0.10–0.20-m layer, with increased microporosity and decreased cryptoporosity and resistance to penetration. The arrangements using single and double paricá lines result in higher volume of available water and greater soil compaction.

Variability of physical properties of soil and rice grown under cover crops in crop-livestock integrated system

The production systems of upland rice culture in Mato Grosso are not consolidated yet while the effects of soil physical properties and their correlation with rice yield in crop-livestock integrated systems are not defined as well. Therefore, this study determined the spatial variability of physical properties of soil and rice cultivated in no-tillage system under different cover crops, using principal components analysis and geostatistics. The experiment was conducted in Santa Carmen, northern Mato Grosso. A regular grid with 100 sample points distributed in an area of 26,400 m2 was installed. Soil and rice samples were collected to determine rice variables and soil physical properties. The average rice yield was 1.70 Mg∙ha−1, ranging from 0.70 to 3.12 Mg∙ha−1. The highest yields were observed in consortium with cowpea and brachiaria and were associated with lower incidence of grain spots, despite higher soil density and penetration resistance. The consortium with brachiaria, crotalaria, and sudangrass had lower yields, which was associated with higher incidence of grain spots, despite higher soil macroporosity and total porosity.

Suplementação concentrada para bovinos de corte em sistema de integração lavoura e pecuária no período das águas

Although the production of cattle fed concentrate supplement is growing, its application in association with integrated crop and livestock still needs further studies. This work was objective to evaluate the performance development of cattle grazing Brachiaria brizantha cv. Marandu, consuming four different supplements, MM – mix mineral, SE – energy supplement, SEP – protein and energy supplement and SPE – energy protein and supplement. A total of 100 steers uncastrated, 57 crossbred (Holstein x Nelore) and 43 Nelore, with 15 months of average age and 280 ± 31 kg of body weight. The experiment consisted of four paddocks formed by B. brizantha cv. Marandu. The work was designed as factorial arrangement (2x4) in a completely randomized design, were evaluated two genetic groups and four different formulations of supplements. The quantity of supplements offer of 0.5 kg/animal/day for the SE, SEP and SPE, except the MM offered ad libitum. There was significant effect of genetic group on productive performance of animals, crossbred steers and that had better performance. The average daily and total gain weight, were higher in animals that consumed SE in relation to SM and SPE. The SE, allows animal performance superior to MS and SPE for grazing cattle in integrated crop and livestock during the rainy season. The rearing of crossbred steers (Holstein x Nelore) in integrated crop and livestock during the rainy presents better performance compared to recreate Nelore.

Grão de milheto em suplementos para terminação de bovinos de corte em sistema integração lavoura e pecuária

The objective was to evaluate the performance and economic development of animals receiving four supplements differentiated by the levels of grain of millet as replacement for corn grain, as well as assess nutritional characteristics of pasture of Brachiaria brizantha cv. Marandu in integrated crop and livestock. Used 64 steers, uncastrated, 32 crossbred (Holstein x Nelore) and 32 Nelore, with 20 months average age and 388 ± 26kg initial body weight. The experiment consisted of four paddocks of 4.68 ha, formed by B. brizantha cv. Marandu. The availability of dry matter and potentially digestible dry matter was 5.24t/ha and 3.39t/ha, respectively. The work was designed as a factorial arrangement (2x4) in a completely randomized design to evaluate two genetic groups and four different levels of grain instead of millet to maize grain in the formulation of supplements (0%; 33%; 66% e 100%). The quantity supplied of 4.0kg/animal/day. A significant effect of genetic group on productive performance of animals, and that Nelore steers have better performance. The average daily weight gain, total weight gain and final body weight decreased linearly with the inclusion of millet in supplements. The replacement of 33% of the corn grain millet concentrated supplements promotes reduction in the days required to obtain animal body weight of 450kg.