Analyzing the genotype-by-environment interactions under a randomization-derived mixed model

This article describes procedures for studying parameters connected with the genotype-by-environment interactions appearing in a mixed model derived from the randomization principle. It considers estimation of these parameters and of their meaningful functions. A test for the overall no-interaction hypothesis is described, and relevant tests for some implied hypotheses concerning individual parametric functions are considered. Useful data transformations are proposed that allow the graphic presentation of interesting features of the genotype-by-environment interactions. The theoretical considerations are illustrated by an analysis of the results of a series of trials with pea varieties.     

QTL for yield components and protein content: a multienvironment study of two pea (<Emphasis Type="Italic">Pisum sativum</Emphasis> L.) populations

Quantitative trait loci for yield, yield components and seed protein content were investigated on the basis of experiments performed with two populations of pea (Pisum sativum L.) lines derived from linked crosses between lines Wt11238, Wt3557 and Wt10245 with contrasting characteristics. The yield-related traits were defined as components giving the grain yield in a multiplicative way. The aim was to clarify the genetic architecture of the relation between seed yield, its components and protein content, with a possible inclusion of the role of epistasis in this explanation. To take full advantage of the availability of the two populations, additive QTL effects and both types of epistasis were analysed: the QTL by genetic background interaction and the first-order QTL–QTL interaction. The two hybrid populations differed with respect to the prevailing gene action, which in the Wt11238 × Wt3557 progeny was mainly additive, while in the Wt10245 × Wt11238 progeny mainly epistatic. Some loci with previously reported, large, repeatable, but contradictory effects on yield and protein content were confirmed. New loci with alleles coming from the protein-rich Wt11238 line, positive for yield components, were identified. It was found that the first order QTL–QTL interaction events were more frequent for the loci showing the QTL by genetic background interaction.     

Isolation and analysis of kappa-casein glycomacropeptide from goat sweet whey

Glycomacropeptide (GMP) was purified from goat sweet whey by anion-exchange and hydrophobic interaction chromatography. Approximately 0.06% (w/v) of sweet whey was recovered as GMP. Amino acid analysis of the GMP preparation showed that the content of phenylalanine (an amino acid that does not occur in goat GMP) was negligible, indicating that the GMP was of high purity. The goat GMP contained 25 microg sialic acid per mg of dry weight. This was approximately 3-fold lower than the sialic acid concentration in bovine GMP reported in the literature. Gel electrophoretic results demonstrated that most of the goat GMP occurs as a dimer. The GMP was intensely stained with Coomassie blue in 50% methanol containing 12.5% (w/v) trichloroacetic acid, but showed very weak metachromasia with the same dye in 45% methanol containing 10% acetic acid, a preparation commonly used to stain protein.     

The influence of alternative plant propagation and stand establishment techniques on survival and growth of eastern cottonwood (Populus deltoides Bartr.) clones

Four eastern cottonwood clones, including standard operational clone ST66 and three advanced clonal selections were produced and included in a test utilizing five different plant propagation methods. Despite relatively large first-year growth differences among clones, all clones demonstrated similar responses to the treatments and clone × cutting treatment interactions were generally non-significant. The effects of changing cutting lengths are consistent with previous studies which indicated the potential for increased plant survival and growth with increased cutting lengths. Differences in stored carbohydrate reserves alone do not appear to completely control first-year growth and development of cuttings. First-year growth of 51 cm long cuttings planted 30.5 cm deep was greater than the same cuttings planted 48 cm deep. Stem form of plants derived from whip-tip propagation did not differ from plants derived from standard, unrooted cuttings. This propagation method offers the potential of far greater production capacity from a cutting orchard and rapid bulk-up of new or limited clones. Stand uniformity assessments suggest that surviving trees of each individual cutting treatment exhibit similar levels of growth variation. Optimization of plantation establishment techniques has the potential to increase growth of young Populus plantations.     

Natural Occurrence and Distribution of Fusarium Toxins in Contaminated Barley Cultivars

Grain samples of 15 naturally contaminated barley cultivars, collected after harvest in southeastern Poland, were analysed for occurrence of Fusarium trichothecenes and zearalenone (ZEA). Barley kernels were contaminated with the following toxic metabolites: deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON), nivalenol (NIV), HT-2 toxin (HT-2), T-2 toxin (T-2), diacetoxyscirpenol (DAS), T-2 tetraol and ZEA. Significant correlations between concentrations of individual toxins and the dominant Fusarium species were found. Moreover, significant differences in toxin concentrations between cultivars were detected. Distribution of these mycotoxins was studied in two fractions of kernels (diameter > 2.5 mm and < 2.5 mm). A two-factor analysis of variance revealed significant differences between the two fractions, and between the analysed cultivars. Most of the interactions between fractions and cultivars were also significant. The highest concentration of the analysed toxins was in the fraction of small kernels. Kernel fraction <2.5 mm, although accounting for only 12.8% of sample weight, contained high proportions of the total toxin content: 80% of DON, 94% of NIV, 85% of ZEA, 83% of T-2 tetraol, 80% of DAS, 68% of HT-2 toxin and 81% of T-2 toxin. The results indicate that the level of contamination with Fusarium trichothecenes and ZEA, can be reduced by rejection of small kernels.     

Scab Response and Moniliformin Accumulation in Kernels of Oat Genotypes Inoculated with Fusarium avenaceum in Poland

Inoculation experiments with 14 genotypes of oats (10 cultivars and 4 lines) were performed during 1996, 1997 and 1998 in Sitaniec, South-Eastern Poland. Panicles of oats were inoculated with a conidial suspension of Fusarium avenaceum, which caused a reduction in yield by 33% and in 1000 kernel weight (TKW) by 21%. During the period between inoculation and harvest, F. avenaceum was able to accumulate moniliformin (MON) in kernels at an average level of 0.13mgkg^–1 (gg^–1). The highest reduction of yield components caused by the F. avenaceum inoculation was found for cv. Santor, followed by lines CHD 1171, STH 2795 and cvs: Kwant and Farys, while cvs Slawko, Dukat, Borys and Komes exhibited the highest resistance to the disease in terms of TKW and yield reductions after inoculation.     

The effect of feed supplementation with a copper‐glycine chelate and copper sulphate on selected humoral and cell‐mediated immune parameters,plasma superoxide dismutase activity,ceruloplasmin and cytokine concentration in broiler chickens

The varied bioavailability and different effects of organic forms of copper on the immune system of poultry have prompted the search for new feed additives based on copper compounds containing modified chelate complexes. The aim of the study was to determine the effect of inorganic and organic forms of copper on selected parameters of the cellular and humoral immune response in broiler chickens by determining the percentages of CD3⁺CD4⁺, CD3⁺CD8⁺ and CD25⁺ lymphocytes, cells with MHC Class II expression, and BU‐1⁺ cells, as well as the concentrations of SOD, IL‐2, IL‐10 and TNF‐α in the peripheral blood. The experiments were conducted using 500 one‐day‐old Ross 308 roosters divided into five groups. Cu was added in inorganic form (CuSO₄), in inorganic form with the addition of phytase (CuSO4 + F), in organic form in combination with glycine (Cu‐Gly) and in organic form in combination with glycine and a phytase supplement (Cu‐Gly+F). The results of the study indicate an increase in the percentage of CD3⁺CD4⁺ and CD3⁺CD8⁺ T lymphocytes, CD25⁺ T cells, and cells expressing MHC class II molecules, and in the concentration of ceruloplasmin, activity of superoxide dismutase and the concentration of IL‐2 in the groups that received copper, particularly copper‐glycine chelates. Based on the study, we can conclude that supplementation of poultry feed with copper chelates activates mainly the Th1 cellular immune response and the response of peripheral blood T lymphocytes. Furthermore, it promotes secretion of cytokines, which are involved in potentiation and regulation of the immune response in birds.     

Influence of graded inclusion of white lupin (Lupinus albus) meal on performance,nutrient digestibility and intestinal morphology of broiler chickens

1. The aim of this study was to investigate the effect of white lupin (Lupinus albus) meal (WLM) addition on the intestinal viscosity, bird performance, nutrient utilisation and villi morphology of growing broiler chicks.

2. The experiment was conducted with 480 broiler chicks divided into 6 dietary treatments, including a maize-soybean meal control diet (CON) and 5 experimental diets containing 100, 150, 200, 250 and 300 g/kg WLM.

3. During the period from d 0 to 35, birds fed on 200 or higher WLM/kg were characterised by lower body weight gain and feed intake than CON. The use of 150 g of WLM/kg increased feed conversion ratio (FCR) compared to CON treatment. Apparent metabolisable energy corrected to zero N balance (AME_N) and apparent ileal digestibility of dry matter, ether extract, crude protein and starch, linearly decreased as WLM increased from 0 to 300 g/kg.

4. There was a quadratic effect of WLM dose on sialic acid excretion. A strong negative linear correlation was found between the excretion of sialic acid and AME_N. The viscosity of ileal digesta was linearly increased as WLM increased. The effect of WLM dose on ileum villus height (VH) was linear, while that on ileum villus area (VA) was quadratic. Both parameters decreased as WLM increased from 0 to 300 g/kg.

5. In conclusion, the use of over 150 g/kg of WLM in broiler diets depressed performance results. However, depression of nutrient utilisation was only observed when 250 or 300 g/kg of WLM was used.

     

Surgical denervation of porcine ovaries during the middle luteal phase of the oestrous cycle changes their morphology and steroidogenic activity

Changes in both the morphology and the steroidogenic activity of porcine ovaries denervated surgically on day 12 of the oestrous cycle were studied. Neurectomy of the plexus and the superior ovarian nerves caused a dramatic reduction in the number (or even a disappearance) of dopamine-beta-hydroxylase- and/or neuropeptide tyrosine-immunoreactive nerve terminals. On day 20 of the subsequent oestrous cycle, the number of small follicles increased (P < 0.01) and that of large follicles decreased (P < 0.05) in the denervated ovaries, as compared to the controls. Neurectomy led to a decrease in the level of progesterone (P4; P < 0.001) and androstenedione (A4; P < 0.01) in the fluid from small follicles, A4 (P < 0.001) and testosterone (T; P < 0.05) in the fluid from medium-sized follicles, as well as in the content of all these steroids in the fluid from large-sized follicles (P < 0.001 for P4 and P < 0.05 for A4 and T). Denervation also caused a decrease in the content of A4 (P < 0.01) and T (P < 0.001) in the wall of follicles. Neurectomy resulted in a significant increase in the immunoexpression of cholesterol side-chain cleavage cytochrome P450 in the follicles and a decrease of 33-hydroxysteroid dehydrogenase. After denervation, plasma levels of LH, P4, A4, T, oestrone and oestradiol-17beta were lower (P < 0.05-0.001) on the particular days of the study than in the control group. Our data revealed that the denervation of ovaries during the middle luteal phase of the oestrous cycle in gilts caused distinct changes in both the morphology and the steroidogenic activity of the organ, confirming an important role of the peripheral nervous system in the control of the gonad in this species.