Produção e composição do leite de ovelhas da raça bergamácia suplementadas com óleo de linhaça (Linum usitatissimum L.)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Morfoanatomia e ontogênese de frutos e sementes de três espécies de Chamaecrista moench (Fabaceae, Caesalpinioideae) de cerrado do Estado de São Paulo

Pós-graduação em Ciências Biológicas (Botânica) - IBB

Efeito de adubação orgânica e mineral e culturas de entressafra na cultura da soja (Glycine max (L) Merrill) no sistema plantio direto

Pós-graduação em Agronomia - FEIS

Implications of the use of sorghum in broiler production

This study aimed at evaluating total or partial replacement of corn by sorghum in broiler diets and at estimating the effect of the pigment supplementation on broiler performance, carcass and cuts yield, and possible breast and leg pigmentation. We used 1680 one-d-old Ross® 308 broilers. Birds were sexed and distributed according to a completely randomized design (2 x 3 + 1). Treatments consisted of a control diet based on corn and diets with two levels corn replacement by sorghum (50 and 100%) and three pigments levels, with four replicates of 60 birds per treatment. There was no effect (p > 0.05) of the dietary replacement of corn by sorghum on performance, carcass and parts yield, and no changes in breast and leg meat pH (p >0.05). Meat redness (a*), yellowness (b*) and luminosity (L*) increased (p < 0.05) as pigment inclusion levels increased. It was concluded that the use of sorghum instead of corn did not affect broiler performance or carcass and cuts yield. When adequate pigments were used, meat color significantly improved.

Analysis of the intestinal bacterial microbiota in maize- or sorghum-fed broiler chickens using real-time PCR

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of the particle size of maize, rice, and sorghum in extruded diets for dogs on starch gelatinization, digestibility, and the fecal concentration of fermentation products

The influence of rice, maize, and sorghum raw material particle size in extruded dry dog food on the digestibility of nutrients and energy and the fecal concentration of fermentation products was investigated. Three diets with similar nutrient compositions were formulated, each with 1 starch source. Before incorporation into diets, the cereals were ground into 3 different particle sizes (approximately 300, 450, and 600 mu m); therefore, a total of 9 diets were in a 3 x 3 factorial arrangement (3 cereals and 3 particle sizes). Fifty-four beagle dogs (12.0 +/- 0.1 kg BW) were randomly assigned to the diets, with 6 dogs per diet. The digestibility was measured with the chromium oxide method. The data were evaluated with ANOVA considering the carbohydrate source, grinding effect, and interactions. The means were compared with the Tukey test and polynomial contrasts (P &lt; 0.05). With the same grinding procedure, rice was reduced to smaller particles than other cereals. The cereal mean geometric diameter (MGD) was directly related to starch gelatini-zation (SG) during extrusion. For rice diets, the MGD and SG did not change nutrient digestibility (P &gt; 0.05); only GE digestibility was reduced at the largest MGD (P &lt; 0.01). For maize and sorghum diets, the total tract apparent nutrient digestibility was reduced for foods with greater MGD and less SG (P &lt; 0.01). A linear reduction in nutrient digestibility according to cereal particle size was observed for sorghum (r(2) &lt; 0.72; P &lt; 0.01). Higher concentrations of fecal total shortchain fatty acids (SCFA) were observed for sorghum diets (P &lt; 0.05) than for other diets. The rice diets led to the production of feces with less lactate (P &lt; 0.05). The increase in raw material MGD did not influence fecal SCFA for rice diets, but for the dogs fed maize and sorghum foods, an increase in propionate and butyrate concentrations were observed as MGD increased (P &lt; 0.05). In conclusion, for dogs fed different particle sizes of the cereal starches in the extruded diets, the digestibility and fecal characteristics were affected, and this effect was ingredient dependent.

Markers associated with stalk number and suckering in sugarcane colocate with tillering and rhizomatousness QTLs in sorghum

Two important factors influencing sugar yield, the primary focus of sugarcane plant breeding programs, are stalk number and suckering. Molecular markers linked to both of these traits are sought to assist in the identification of high sugar yield, high stalk number, low-suckering sugarcane clones. In this preliminary mapping study, 108 progeny from a biparental cross involving two elite Australian sugarcane clones were evaluated at two sites for two years for both stalk number and suckering. A total of 258 DNA markers, including both restriction fragment length polymorphisms (RFLPs) and radio-labelled amplified fragments (RAFs), were scored and evaluated using single-factor analysis. Sixteen (7 RFLPs and 9 RAFs) and 14 (6 RFLPs and 8 RAFs) markers were identified that were significantly associated (P < 0.01) with stalk number and suckering, respectively, across both years and sites. The seven and six RFLP markers associated with stalk number and suckering, respectively, were generated by eight different RFLP probes, of which seven had been mapped in sorghum and (or) sugarcane. Of significant interest was the observation that all seven RFLP probes could be shown to be located within or near QTLs associated with tillering and rhizomatousness in sorghum. This observation highlights the usefulness of comparative mapping between sorghum and sugarcane and suggests that the identification of useful markers for stalk number and suckering in sugarcane would be facilitated by focussing on sorghum QTLs associated with related traits.

Potential yield and water-use effficiency benefits in sorghum from limited maximum transpiration rate

Limitations on maximum transpiration rates, which are commonly observed as midday stomatal closure, have been observed even under well-watered conditions. Such limitations may be caused by restricted hydraulic conductance in the plant or by limited supply of water to the plant from uptake by the roots. This behaviour would have the consequences of limiting photosynthetic rate, increasing transpiration efficiency, and conserving soil water. A key question is whether the conservation of water will be rewarded by sustained growth during seed fill and increased grain yield. This simulation analysis was undertaken to examine consequences on sorghum yield over several years when maximum transpiration rate was imposed in a model. Yields were simulated at four locations in the sorghum-growing area of Australia for 115 seasons at each location. Mean yield was increased slightly ( 5 - 7%) by setting maximum transpiration rate at 0.4 mm h(-1). However, the yield increase was mainly in the dry, low-yielding years in which growers may be more economically vulnerable. In years with yield less than similar to 450 g m(-2), the maximum transpiration rate trait resulted in yield increases of 9 - 13%. At higher yield levels, decreased yields were simulated. The yield responses to restricted maximum transpiration rate were associated with an increase in efficiency of water use. This arose because transpiration was reduced at times of the day when atmospheric demand was greatest. Depending on the risk attitude of growers, incorporation of a maximum transpiration rate trait in sorghum cultivars could be desirable to increase yields in dry years and improve water use efficiency and crop yield stability.

A simple regional-scale model for forecasting sorghum yield across North-Eastern Australia

Sorghum is the main dryland summer crop in NE Australia and a number of agricultural businesses would benefit from an ability to forecast production likelihood at regional scale. In this study we sought to develop a simple agro-climatic modelling approach for predicting shire (statistical local area) sorghum yield. Actual shire yield data, available for the period 1983-1997 from the Australian Bureau of Statistics, were used to train the model. Shire yield was related to a water stress index (SI) that was derived from the agro-climatic model. The model involved a simple fallow and crop water balance that was driven by climate data available at recording stations within each shire. Parameters defining the soil water holding capacity, maximum number of sowings (MXNS) in any year, planting rainfall requirement, and critical period for stress during the crop cycle were optimised as part of the model fitting procedure. Cross-validated correlations (CVR) ranged from 0.5 to 0.9 at shire scale. When aggregated to regional and national scales, 78-84% of the annual variation in sorghum yield was explained. The model was used to examine trends in sorghum productivity and the approach to using it in an operational forecasting system was outlined. (c) 2005 Elsevier B.V. All rights reserved.

Resistance gene analogues in sugarcane and sorghum and their association with quantitative trait loci for rust resistance

Fifty-four different sugarcane resistance gene analogue (RGA) sequences were isolated, characterized, and used to identify molecular markers linked to major disease-resistance loci in sugarcane. Ten RGAs were identified from a sugarcane stem expressed sequence tag (EST) library; the remaining 44 were isolated from sugarcane stem, leaf, and root tissue using primers designed to conserved RGA motifs. The map location of 31 of the RGAs was determined in sugarcane and compared with the location of quantitative trait loci (QTL) for brown rust resistance. After 2 years of phenotyping, 3 RGAs were shown to generate markers that were significantly associated with resistance to this disease. To assist in the understanding of the complex genetic structure of sugarcane, 17 of the 31 RGAs were also mapped in sorghum. Comparative mapping between sugarcane and sorghum revealed syntenic localization of several RGA clusters. The 3 brown rust associated RGAs were shown to map to the same linkage group (LG) in sorghum with 2 mapping to one region and the third to a region previously shown to contain a major rust-resistance QTL in sorghum. These results illustrate the value of using RGAs for the identification of markers linked to disease resistance loci and the value of simultaneous mapping in sugarcane and sorghum.

Investigating the use of sweet sorghum as a model for sugar accumulation in sugarcane

This paper outlines a current investigation of sugar accumulation in sweet sorghum to assist in understanding and simplifying this complex trait in sugarcane. A recombinant inbred line (RIL) sorghum population, between a sweet and a grain sorghum, has been developed and phenotyped for various morphological and agronomic traits related to grain yield, biomass and stem sugar content. A genetic linkage map will be constructed for the sweet sorghum population with the objective of identifying genomic regions associated with sucrose accumulation in sweet sorghum. This will lead to further work, including comparative mapping in sugarcane, to identify the extent to which sweet sorghum can be used as a model for investigating sugar accumulation in sugarcane.

Soil exploration by sorghum root systems in wide row cropping systems

Wide and ‘skip row’ row configurations have been used as a means to improve yield reliability in grain sorghum production. However, there has been little effort put to design of these systems in relation to optimal combinations of root system characteristics and row configuration, largely because little is known about root system characteristics. The studies reported here aimed to determine the potential extent of root system exploration in skip row systems. Field experiments were conducted under rain-out shelters and the extent of water extraction and root system growth measured. One experiment was conducted using widely-spaced twin rows grown in the soil. The other experiment involved the use of specially constructed large root observation chambers for single plants. It was found that the potential extent of root system exploration in sorghum was beyond 2m from the planted rows using conventional hybrids and that root exploration continued during grain filling. Preliminary data suggested that the extent of water extraction throughout this region depended on root length density and the balance between demand for, and supply of, water. The results to date suggest that simultaneous genetic and management manipulation of wide row production systems might lead to more effective and reliable production in specific environments. Further study of variation in root-shoot dynamics and root system characteristics is required to exploit possible opportunities.