Optimum number of crosses and progeny per cross in breeding self-fertilizing crops. I. General approach and first numerical results

Summary Based on maximization of selection response, Peek (1986) proposed methodology for determining the optimum number of crosses and progeny per cross in breeding self-fertilizing crops. By this method the total selection response is obtained by adding the individual responses from the two steps of selection: selection between crosses and selection within crosses. In this paper, Peek's approach has been generalized for finite or nonnormal populations. Optimum numbers of crosses are determined by testing capacity, number of selected crosses, number of selected lines from each selected cross, and heritability.In the case selection of the best line from the best cross, the optimum number of crosses increases monotonically with increasing testing capacity (for any given fixed heritability). For increasing heritabilities, however, the optimum number of crosses exhibits relatively flat maxima (for any given fixed testing capacity). These maxima are located at intermediate or sub-intermediate heritabilities.For varying numbers of selected crosses and selected lines from each selected cross the main results are: The optimum number of crosses i) increases with increasing testing capacity, ii) increases with increasing number of selected crosses and iii) decreases with increasing number of selected lines from each selected cross.     

Der Genfonds anMalus-Arten in der DDR und seine Nutzung

Zusammenfassung Die ursprüngliche Naumburger Malus-Artenkollektion wurde in das Institut für Obstforschung Dresden-Pillnitz überführt. Sie umfaßt 237 Arten und Varietäten und damit die wichtigsten Vertreter der 5 Sektionen vonMalus - Malus, Sorbomalus, Chloromeles, Eriobolus, Docyniopsis (nachRehder 1954). Die bereits vorliegenden Untersuchungsergebnisse an dieser Kollektion über Pollenfertilität, Apomixis, Schorf-, Mehltau- und Blutlausresistenz sowie Virustoleranz werden mitgeteilt.Auf die nationale und internationale Bedeutung dieses Genfonds, der für den Austausch zur Verfügung steht, wird hingewiesen.

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Genetic resources ofMalus in the GDR and their utilization

Summary The collection ofMalus germplasm originally located in Naumburg has been transfered to the Institute of Fruit Research in Dresden-Pillnitz. It contains 237 species and forms and therewith important representatives of the 5 sections ofMalus - Malus, Sorbomalus, Chloromeles, Eriobolus, Docyniopsis (according toRehder 1954). The results already obtained on the basis of this germplasm concerning pollen fertility, apomixis, resistance to scab, mildew, woolly aphid, and virus tolerance are presented here. The national and international importance of thisMalus collection which is available for distribution is stressed.

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Malus

Malus, . , -. 237 :Malus, Sorbomalus, Chloromeles, Eriobolus, Docyniopsis ( , 1954). , , , , , , , . , , , .

     

A simplified extraction schema to for the analytical characterization of apple orchard soils

Purpose

Standardized procedures for agricultural soil analysis use different extractant solutions, to determine one or just a few elements, which needs a lot of time and manpower. Within this work, it was tried to substitute traditional methods by the use of multi-element determination techniques, like inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) applied to a few solutions.

Material and methods

ICP-OES and ICP-MS have been applied to a sequence of extracts obtained with 0.16 M acetic acid and 0.1 M oxalate buffer pH 3, which are more suitable for the plasma than traditional salt extractant solutions. Dilute acetic acid should characterize exchangeables plus carbonates, and oxalate buffer the pedogenic oxides. Aqua regia extractions in glass have been replaced by pressure digestion with KClO₃ in dilute nitric acid, which yields results equivalent to aqua regia, and additionally permits the determination of total sulfur, as well as acid-leachable boron and silicon. Total digestion was done in PTFE beakers by fuming with HNO₃/HClO₄, subsequently with HF, and final uptake in 1?+?1 HCl.

Results and discussion

The method was applied to 44 soils from apple orchards of different soil types and climatic zones. P and K obtained from standard acetate-lactate extract as well as B obtained from the Baron extract correlated with the results from the acetic acid extract better than 0.9. Just Mg from the CaCl₂ extract (Schachtschabel) was independent from all other Mg fractions. The results of the total digests could be verified by XRF analysis of the solid, Ti recovery was the most critical item. The results for Ca, Cu, Mg, Mn, Sr, Pb, and Zn obtained from KClO₃ digest and from totals, were strongly correlated. Factor analysis showed that the fraction mobilized by dilute acetic acid contained Ca-Mg-carbonates as well as Al-Ba-Na in the first factor, K-P-S in a second, whereas Mn-La-Li formed a group of its own. The pedogenic oxides, obtained from Al-Fe-Mn-Ti released in oxalate, carry most of the cationic trace elements, whereas the anions P-S-B-Si and the essentials Cu-Mo form different groups. Among the main elements, the quasi-total data were much less intercorrelated than the totals. The rare earth elements formed a strongly intercorrelated group as well after total digestion as in the oxalate leach.

Conclusions

The proposed method permits to obtain information about common cations including trace elements, and the nonmetals phosphorus, silicon, sulfur, boron, and iodine simultaneously, which could be a gate to find new relations among them. The two-step procedure permits to predict availabilities in shorter and longer periods of time. Data from the extract in dilute acetic acid for K, P, and B can substitute traditional methods of soil analysis.

     

Detection of colostrum-derived alloantibodies in calves with bovine neonatal pancytopenia

Receptors of the immunoglobulin-like superfamily are critically involved in virtually every aspect of immune responses. One large chromosomal area encoding such immunoregulatory receptors is the leukocyte receptor cluster. Here we review various aspects of the chicken Ig-like receptor (CHIR) family, located on microchromosome 31, an orthologous position to the mammalian leukocyte receptor cluster. The CHIR family has been massively expanded with over hundred CHIR genes that are further distinguished into activating, inhibitory and bifunctional receptors. Comparisons of various features such as amino acid motifs, genomic structure, expression and associated adaptor molecules reveal the homology of CHIR to both the killer Ig-like and the leukocyte Ig-like receptor families, with most pronounced correlation of certain CHIR to the NK cell receptor KIR2DL4. To date the CHIR ligands remain largely obscure with the exception of CHIR-AB1 that binds to chicken IgY. Detailed analyses of CHIR-AB1, its crystal structure, the interaction to IgY and functional capabilities allow us to draw conclusions regarding Fc receptor phylogeny and function.     

Long-term effects of intermittent equine parathyroid hormone fragment (ePTH-1-37) administration on bone metabolism in healthy horses

Intermittent administration of parathyroid hormone (PTH) is an anabolic therapy for osteoporotic conditions in humans. This study evaluated the effects of equine PTH fragment (ePTH-1-37) administration on bone metabolism in 12 healthy horses. Six horses each were treated once daily for 120days with subcutaneous injections of 0.5μg/kg ePTH-1-37 or placebo. Blood was collected to determine ionized calcium (Ca(++)), total Ca (Ca(T)), inorganic phosphorus, serum equine osteocalcin (eOC), carboxy-terminal telopeptide of type I collagen (ICTP), bone-specific alkaline phosphatase, and carboxy-terminal cross-linked telopeptide of type I collagen. Bone mineral density (BMD) was determined with dual X-ray absorptiometry of the metacarpus and calcaneus. Significantly higher blood Ca(++) and plasma Ca(T) concentrations were measured 5h after ePTH-1-37 administration compared to placebo. Higher serum eOC concentrations were found for ePTH-1-37 treatment at days 90 (P<0.05) and 120 (P=0.05). Significantly higher serum ICTP levels were observed with ePTH-1-37 treatment at days 60 and 90. For both study groups, BMD increased significantly in the calcaneus. Long-term use of ePTH-1-37 seemed to have no negative effects on bone metabolism in healthy horses. The absence of undesirable side effects is the premise to ensure safety for further clinical investigations in horses with increased bone resorption processes.     

Evaluation of the influences of exercise, birth date, and osteochondrosis on plasma bone marker concentrations in Hanoverian Warmblood foals

OBJECTIVE: To determine whether plasma concentrations of bone turnover markers in growing Hanoverian foals are influenced by age, housing conditions, or osteochondrosis. ANIMALS: 165 healthy foals and 119 foals with osteochondrosis. PROCEDURES: Foals were allocated according to birth date and housing management into groups of early-born (born before March 31, 2001; n = 154 foals, 88 of which were healthy and 66 of which had osteochondrosis) and late-born (born after March 31, 2001; 130 foals, 77 of which were healthy and 53 of which had osteochondrosis) foals. Plasma osteocalcin and carboxyterminal propeptide of type I collagen concentrations were analyzed as markers of bone formation, and carboxyterminal telopeptide of type I collagen concentration was analyzed as a marker of bone resorption. Foals underwent radiographic evaluation to screen for osteochondrosis. RESULTS: Plasma concentrations of osteocalcin, carboxyterminal propeptide of type I collagen, and carboxyterminal telopeptide of type I collagen decreased with age, but these changes were more distinct in late-born foals than in early-born foals. Neither sex nor predisposition to develop osteochondrosis affected the pattern of bone marker changes in either group. CONCLUSIONS AND CLINICAL RELEVANCE: An age-related decrease in concentrations of bone markers was seen during the first 200 days of life. Changes in bone marker concentrations were similar for foals with osteochondrosis and healthy foals. The correlation between the decrease in bone marker concentration and date of birth indicates that there are differences in skeletal development between early- and late-born foals.     

In-vitro susceptibility testing of Leptospira by a modified broth microdilution methods

In Germany, the application of antimicrobial agents represents the method of choice to control infections of food-producing animals by bacteria of the genus Leptospira. However, only few data are available on the susceptibility of Leptospira spp. against antimicrobial agents and the in vivo efficacy of antimicrobial agents. Based on a modified broth microdilution method, a standardised in-vitro susceptibility testing system for Leptospira spp. was established which also included quality control aspects. Considering the minimum inhibitory concentrations determined in this study in-vivo efficacy is expected for the following classes of antimicrobial agents: penicillins, cephalosporins, macrolides, lincosamides, fluoroquinolones, phenicols, and in part also for aminoglycosides and tetracyclines. Clinical aspects and bioavailability of the drugs in the target tissues have to be taken into account. Penicillins and aminoglycosides as commonly used inhibitory supplements in semen extender seem to be effective against leptospires.     

Ultrasonographic imaging of abomasal milk clotting and abomasal diameter in healthy and diarrheic calves

In case of diarrhea calves are treated with oral rehydration solutions (ORS), which are known to increase abomasal pH and inhibit milk clotting in vitro. Nevertheless, recent studies have shown that ORS with HCO₃^‐ ≤ 62 mmol/L do not interfere with abomasal milk clotting in healthy calves. However, in diarrheic calves, feeding ORS and milk simultaneously may disturb abomasal curd formation and exacerbate diarrhea due to faster abomasal passage of ingesta. Therefore, the aim of the present study was to ultrasonographically examine abomasal milk clotting and diameter after feeding milk and milk replacer (MR) with and without ORS to healthy and diarrheic calves. Abomasal curd formation and diameter in healthy and diarrheic calves were ultrasonographically imaged before and after feeding milk, MR and ORS prepared in milk or MR. Feeding mixtures of milk or MR with ORS did not cause any remarkable differences in the ultrasonographic images of abomasal content. Moreover, abomasal milk clotting was not disturbed due to diarrhea. Statistically significant differences of abomasal diameter after feeding between healthy and diarrheic calves indicated that abomasal emptying is delayed in diarrheic calves. Hence, further studies are needed to determine reasons for decelerated abomasal passage in calves suffering from diarrhea.     

Characterization of cation exchange capacity (CEC) for agricultural land-use areas

Spatial assessment of soil properties needs conversion of point data to an area-oriented model. Methods are required that create a reproducible map. The development of a map is shown by the example of cation exchange capacity. Twenty sorption types are formed and derived from the vertical sequence of values for substrate types and are aggregated to six main types. A qualitative assessment of the main CEC sorption types is carried out with comparative ranking. The association of different substrate types on an areal soil pattern requires the identification of sorption association types. These are shown by the areal share of the main sorption types for the substrate types involved in each case. For interpreting the site parameters from the MMK (Mittelmaßstäbige Landwirtschaftliche Standortkartierung), the procedure is presented in detail. An example of the results is shown with CEC maps. Tables complement the visualization for different areas, defined by administrative or natural landscape boundaries. The application of this method for relative evaluation of CEC is demonstrated using KA5-rules. The CEC characterization of agricultural areas can be reproduced on the basis of the mapping units of soil maps with different scales (BÜK 200). The areal-specific labeling of CEC constitutes soil-related decision guideline.