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PubMed1999

Long-term trend toward earlier breeding in an American bird: a response to global warming?

In regions with severe winters, global warming may be expected to cause earlier onset of breeding in most animals, yet no documentation of such a trend exists in North America. In a study of marked individuals of the Mexican jay (Aphelocoma ultramarina) in southeastern Arizona, from 1971 to 1998, the mean Julian date of first clutch in the population declined significantly by 10.1 days. The date of the first nest in the population also became earlier, by 10.8 days. These changes were associated with significant trends toward increased monthly minimum temperatures on the study area, traits that are associated with the onset of breeding in this population. Significant trends from 1971 to 1997 toward warmer minimum temperatures in the months before and during the initiation of breeding were observed. These trends parallel changes in minimum temperatures and community composition in a recent study of grassland ecology in the western United States. Together, they suggest that more attention should be given to the possible ecological importance of global change in minimum temperatures.

Animals↗
PubMed2002

Effects of dietary fat source and breed on the carcass composition, n-3 polyunsaturated fatty acid and conjugated linoleic acid content of sheep meat and adipose tissue.

Seventy-two 8-week-old ram lambs from three breeds, Suffolk, Soay and Friesland, were offered one of four diets based on dried grass and formulated to have a similar fatty acid content (60 g/kg DM) and containing: Megalac (high in 16 : 0, control; Volac Ltd, Royston, Herts., UK), whole linseed (18 : 3n-3), fish oil (20 : 5n-3 and 22 : 6n-3) or whole linseed plus fish oil. The lambs were slaughtered at approximately half of their mature live weight (43, 21 and 43 kg for Suffolk, Soay and Friesland lambs, respectively). Fish oil reduced DM intake and lamb live-weight gain (P<0.001), while DM intake, live-weight gain and subcutaneous fat content were highest in Suffolk and lowest in Soay lambs. Linseed feeding doubled the proportion (x100) of 18 : 3n-3 in the longissimus dorsi from 1.4 to 3.1 and in the subcutaneous adipose tissue from 1.2 to 2.6 (P<0.001). Suffolk and particularly Soay lambs contained higher proportions of 18 : 3n-3 than Friesland lambs in the longissimus dorsi, while in the adipose tissue, Suffolk lambs had the highest level. Feeding fish oil increased the muscle proportion (x100) of 20 : 5n-3 from 0.7 to 2.3 and 22 : 6n-3 from 0.3 to 0.8 (P<0.001). By contrast, the proportions of the longer-chain n-3 polyunsaturated fatty acids were similar across all three breeds. All three lipid supplements containing n-3 polyunsaturated fatty acids increased the content of muscle trans-18 : 1 relative to the control values, but conjugated linoleic acid (cis-9,trans-11-18 : 2) only increased in the muscle of lambs fed linseed. Feeding linseed or fish oil lowered the n-6 : n-3 ratio in sheep meat, but neither diet nor breed had much effect on the polyunsaturated fatty acid: saturated fatty acid ratio.

Adipose Tissue↗
PubMed2003

Micronutrient fortification of plants through plant breeding: can it improve nutrition in man at low cost?

Can commonly-eaten food staple crops be developed that fortify their seeds with essential minerals and vitamins? Can farmers be induced to grow such varieties? If so, would this result in a marked improvement in human nutrition at a lower cost than existing nutrition interventions? An interdisciplinary international effort is underway to breed for mineral- and vitamin-dense varieties of rice, wheat, maize, beans and cassava for release to farmers in developing countries. The biofortification strategy seeks to take advantage of the consistent daily consumption of large amounts of food staples by all family members, including women and children as they are most at risk for micronutrient malnutrition. As a consequence of the predominance of food staples in the diets of the poor, this strategy implicitly targets low-income households. After the one-time investment is made to develop seeds that fortify themselves, recurrent costs are low and germplasm may be shared internationally. It is this multiplier aspect of plant breeding across time and distance that makes it so cost-effective. Once in place, the biofortified crop system is highly sustainable. Nutritionally-improved varieties will continue to be grown and consumed year after year, even if government attention and international funding for micronutrient issues fades. Biofortification provides a truly feasible means of reaching malnourished populations in relatively remote rural areas, delivering naturally-fortified foods to population groups with limited access to commercially-marketed fortified foods that are more readily available in urban areas. Biofortification and commercial fortification are, therefore, highly complementary. Breeding for higher trace mineral density in seeds will not incur a yield penalty. Mineral-packed seeds sell themselves to farmers because, as recent research has shown, these trace minerals are essential in helping plants resist disease and other environmental stresses. More seedlings survive and initial growth is more rapid. Ultimately, yields are higher, particularly in trace mineral-'deficient' soils in arid regions.

Biological Availability↗
PubMed1987

Studies on the dynamics of transmission of onchocerciasis in a Sudan-savanna area of North Cameroon I. Prevailing Simulium vectors, their biting rates and age-composition at different distances from their breeding sites.

Along the main water courses in the sparsely populated areas of the Sous-Préfecture of Tcholliré, the vectors of onchocerciasis were mainly Simulium damnosum s. str. and S. sirbanum, together with a small proportion of S. squamosum. Over a period of one to three years, vector biting rates were measured at 23 fly-catching sites in the vicinities of nine villages with different endemicities of onchocerciasis. Annual Biting Rates (ABR) on man were estimated as 26,100-83,800 fly-bites per man per year along the rivers Mayo Rey and Vina du Nord, and 11,000-37,400 at rainy season tributaries. Biting rates decreased rapidly at increasing distances from the river, and were between 10,700 and 2400 at 2-10 km cross-country from the breeding site. Lowest biting rates (50-6000) were measured at the village centres. The ABR varied from year to year in relation to the water-discharge of the main rivers, the coefficient of variation of the mean being 34-49%. The parous rates were 64-73% at the perennial breeding sites and only 17-44% away from the breeding sites, indicating dispersal mainly of young nulliparous flies and a reduced flight-range after oviposition.

Age Factors↗
PubMed1977

The relative growth of internal organs in light and heavy breeds.

The relative weights of the gastro-intestinal segments and of some other internal organs from light and heavy breed chicks from hatching to 21 days of age were compared. 2. The relative weight of the duodenum and jejunum was higher in the light breed than in the heavy one, the reverse relationship was found for the ileum and caecum. 3. The relative growth of the pancreas, heart, cerebrum and cerebellum was greater in the light breed.

Animals↗
PubMed1992

Breed differences in the histochemical properties of the M. iliotibialis lateralis myofibre of domestic cocks.

1. Reduced nicotinamide adenine dinucleotide dehydrogenase (NADH-DH) activity in the M. iliotibialis lateralis was compared histochemically among 7 breeds of cocks. This muscle was composed only of Type-IIA and -IIB fibres. 2. Apparent breed differences were observed in muscle development, the NADH-DH activity in every fibre type, fibre type distribution and fibre diameters. 3. From the results of this study, it was concluded that the muscle characteristics of various breeds were based not only on the fibre type composition, but also the different activities of oxidative enzyme in every type.

Animals↗
PubMed1991

The incidence of PHTVL/PHPV in Doberman and the results of breeding rules.

Between 1967 and 1987, in the Netherlands 3,775 Dobermans were examined for hereditary eye diseases. In 238 of these dogs severe persistent hyperplastic tunica vasculosa lentis and primary vitreous (PHTVL/PHPV) was diagnosed. After a brief description of the clinical features the results of breeding over the recent years are discussed. The incidence (1978-1987) of severely affected dogs in the litter controls decreased from 5% to 1% in the individual controls from 19% to 8%. This is an encouraging downward tendency. Better results are to be expected once test mating and progeny-testing methods are accepted as breeding methods in dog breeding.

Animals↗
PubMed2001

Population parameters to compare dog breeds: differences between five Dutch purebred populations.

Differences in five purebred dog populations born in 1994 in the Netherlands were evaluated using different parameters. Numerically, the Golden Retriever was the largest breed (840 litters of 234 sires) and the Kooiker Dog (101 litters of 41 sires) the smallest. The litter per sire ratio was largest in the Bernese Mountain Dog (4.59) and lowest in the Kooiker Dog (2.46). The mean relatedness and the actual mean level of inbreeding in the studied generations were 0.102 and 0.056 respectively for the Bernese Mountain Dog, 0.041 and 0.046 for the Bouvier des Flandres, 0.087 and 0.061 for the Boxer, 0.020 and 0.018 for the Golden Retriever, and 0.146 and 0.070 for the Kooiker Dog. Quantification and visualization of population parameters for purebred dogs will facilitate the comparison of breeds and the comparison of breeds in different periods or countries. It appears unlikely that the increase in inbreeding is a major determinant of the possible increase in the frequency of genetic diseases.

Animals↗
PubMed1998

Plant breeding: a long-term strategy for the control of zinc deficiency in vulnerable populations.

Because trace minerals are important not only for human nutrition but for plant nutrition as well, plant breeding holds great promise for making a significant, sustainable, low-cost contribution to the reduction of micronutrient deficiencies in humans. It may also have important spinoff effects for increasing farm productivity in developing countries in an environmentally beneficial way. This article describes ongoing plant breeding research that could increase the intake of bioavailable zinc from food staple crops in vulnerable populations in developing countries. The 3 most promising plant breeding strategies toward this goal are as follows: 1) increasing the concentration of zinc, 2) reducing the amount of phytic acid (a strong inhibitor of zinc absorption), and 3) raising the concentrations of sulfur-containing amino acids (thought to promote zinc absorption) in the plant. The agronomic advantages and disadvantages as well as the potential benefits and limitations of each approach for human nutrition are described. Research is currently underway to identify the optimal combination of these approaches that will maximize the effect on human zinc nutrition.

Biological Availability↗
PubMedDate not supplied

Genetic paternity analysis and breeding success in bluegill sunfish (Lepomis macrochirus).

Fish have some of the most complex mating systems known in the animal kingdom. With the advent of powerful genetic markers and an emerging mathematical framework to calculate parentage, it is now possible to analyze genetic relatedness and gene flow in these systems. An important example is the bluegill sunfish (Lepomis macrochirus) which consists of parental males that provide sole care for the young, cuckolder males that parasitize the parentals, and females that actively choose among males within dense breeding colonies. In this article genetic markers for bluegill are characterized and their utility in parentage studies is demonstrated by calculating the genetic relatedness of parental males to their broods for an entire natural breeding colony. A novel Monte Carlo simulation is developed to calculate the confidence in the relatedness estimates and these data are used to provide an estimate of the mean breeding success of parental and cuckolder males. Finally, the applications of genetic analyses to understanding mating systems, parental care, and life-history evolution in bluegill are discussed.

Alleles↗
PubMed2004

Breeding for micronutrients in staple food crops from a human nutrition perspective.

Over three billion people are currently micronutrient (i.e. micronutrient elements and vitamins) malnourished, resulting in egregious societal costs including learning disabilities among children, increased morbidity and mortality rates, lower worker productivity, and high healthcare costs, all factors diminishing human potential, felicity, and national economic development. Nutritional deficiencies (e.g. iron, zinc, vitamin A) account for almost two-thirds of the childhood death worldwide. Most of those afflicted are dependent on staple crops for their sustenance. Importantly, these crops can be enriched (i.e. 'biofortified') with micronutrients using plant breeding and/or transgenic strategies, because micronutrient enrichment traits exist within their genomes that can to used for substantially increasing micronutrient levels in these foods without negatively impacting crop productivity. Furthermore, 'proof of concept' studies have been published using transgenic approaches to biofortify staple crops (e.g. high beta-carotene 'golden rice' grain, high ferritin-Fe rice grain, etc). In addition, micronutrient element enrichment of seeds can increase crop yields when sowed to micronutrient-poor soils, assuring their adoption by farmers. Bioavailability issues must be addressed when employing plant breeding and/or transgenic approaches to reduce micronutrient malnutrition. Enhancing substances (e.g. ascorbic acid, S-containing amino acids, etc) that promote micronutrient bioavailability or decreasing antinutrient substances (e.g. phytate, polyphenolics, etc) that inhibit micronutrient bioavailability, are both options that could be pursued, but the latter approach should be used with caution. The world's agricultural community should adopt plant breeding and other genetic technologies to improve human health, and the world's nutrition and health communities should support these efforts. Sustainable solutions to this enormous global problem of 'hidden hunger' will not come without employing agricultural approaches.

Biological Availability↗
PubMed2004

Breeding for high water-use efficiency.

There is a pressing need to improve the water-use efficiency of rain-fed and irrigated crop production. Breeding crop varieties with higher water-use efficiency is seen as providing part of the solution. Three key processes can be exploited in breeding for high water-use efficiency: (i) moving more of the available water through the crop rather than it being wasted as evaporation from the soil surface or drainage beyond the root zone or being left behind in the root zone at harvest; (ii) acquiring more carbon (biomass) in exchange for the water transpired by the crop, i.e. improving crop transpiration efficiency; (iii) partitioning more of the achieved biomass into the harvested product. The relative importance of any one of these processes will vary depending on how water availability varies during the crop cycle. However, these three processes are not independent. Targeting specific traits to improve one process may have detrimental effects on the other two, but there may also be positive interactions. Progress in breeding for improved water-use efficiency of rain-fed wheat is reviewed to illustrate the nature of some of these interactions and to highlight opportunities that may be exploited in other crops as well as potential pitfalls. For C3 species, measuring carbon isotope discrimination provides a powerful means of improving water-use efficiency of leaf gas exchange, but experience has shown that improvements in leaf-level water-use efficiency may not always translate into higher crop water-use efficiency or yield. In fact, the reverse has frequently been observed. Reasons for this are explored in some detail. Crop simulation modelling can be used to assess the likely impact on water-use efficiency and yield of changing the expression of traits of interest. Results of such simulations indicate that greater progress may be achieved by pyramiding traits so that potential negative effects of individual traits are neutralized. DNA-based selection techniques may assist in such a strategy.

Agriculture↗
PubMedDate not supplied

Selective breeding for variations in patterns of mystacial vibrissae of mice. Bilaterally symmetrical strains derived from ICR stock.

The establishment of certain patterns of mystacial vibrissae in mice has been the aim of an extensive breeding program carried on in this laboratory since 1977. In a companion paper we have reported on variations in this pattern in an outbred population of ICR mice. Starting with 21 ICR animals we bred, mostly by brother-sister mating, for 13 bilaterally symmetric patterns of mystacial vibrissae characterized by the presence (or absence) of supernumerary whiskers (SWs). The strains are classified as follows: I, a mouse strain with the standard pattern; II, eight strains bred for the occurrence of SWs at a given site or sites; and III, four mouse strains bred for a maximal number of SWs in different regions of the whiskerpad. Commonly, SWs occur in regions that coincide with the zones of mergence between the three facial processes except for two class II strains in which we bred for SWs in the "straddler" row of vibrissae, and for one class III strain, in which we cultivated the tendency (that appeared late in our program) to have SWs at the crest of a facial process. For classes I and II we analyzed the results for about 18 generations in terms of "improvement," meaning an increase in the percentages of animals with the desired phenotype together with a decreased frequency of undesired SWs. For class III, success in breeding meant the increase of the mean number of the desired SWs. All results led to the same conclusion: there is a genetic basis for the occurrence of SWs. The side preference of a particular SW is not strain dependent. It disappears in those class I and II strains in which almost 100% of animals obtained the desired phenotype. The increase in number of SWs in one zone of mergence does not depend on the presence of SWs in the other. Where tested, we almost always found a representation of an SW in a topologically equivalent location within the "barrelfield" area of the somatosensory cerebral cortex. Except for some diseases early in the breeding program, and some side effects of inbreeding that were eliminated, the population was without obvious defects. Where tested, there was no correlation between the occurrence of SWs and sex. The observed variations in pattern of mystacial vibrissae and their genetic background led us to propose a morphogenetic model for the formation of the pattern of mystacial vibrissae.

Animals↗
PubMed2024

The genomic route to tomato breeding: Past, present, and future.

Over the past 10,000 years, tomato species have undergone both unintentional and intentional selection to enhance their favorable traits for human consumption and manufacturing. These selection processes have significantly influenced the genomes of tomato species and have played a critical role in improving tomato varieties. In this review, we summarize recent advances in tomato genome sequencing, explore the impact of human-driven selection, and recapitulate key genes associated with important agronomic traits in tomato breeding. We provide several examples of genomics-guided tomato breeding to highlight the potential of genome resources in facilitating tomato improvement. Furthermore, we elaborate the progress and strategies of tomato breeding through genome design and present how such efforts can help future enhancements of tomato to align with the demands of sustainability and evolving human societies.

Solanum lycopersicum↗
PubMed1997

Breeding and genetics--historical perspective.

This paper is a review of selection methods that have been used in commercial breeding of table egg stocks, broilers, and turkeys, based on the author's experience. In addition, a number of historic developments that have shaped or influenced the selection process are listed and the significance of each is discussed. The merits of mass selection are noted and compared with the multiple forms of family selection, e.g., full or half sibs, progeny testing, and recurrent methods. Each of these methods is believed to have nearly universal application in applied breeding programs being practiced today. This review concludes that a combination of individual and family selection practices aimed at improving multiple traits simultaneously is required to remain a successful supplier of breeding stock to the current commercial industry.

Animal Husbandry↗
PubMed1998

Equipment design for breeding flocks.

Breeding stocks require specialized equipment and facilities that accommodate both sexes and their mating behaviors. Divergence in male and female requirements has occurred due to genetic selection, particularly in heavy meat stocks. Proper equipment design requires specific knowledge about the nutritional requirements, genetics, and behavior of the particular stock within the environment intended. Attention must be paid to the relationship between the rearing and breeding environments, because preferences and behavioral patterns develop at an early age. The "correct" breeding environment is highly dependent upon the growing environment. There is evidence that some undesirable behaviors and poor fertility may arise from inadequate rearing nutrition and that nutrition can influence the development of certain behaviors.

Animal Welfare↗
PubMed2001

Brain alterations in crested versus non-crested breeds of domestic ducks (Anas platyrhynchos f.d.).

A comparison of brain size and brain composition was made between two uncrested duck breeds and Crested Ducks (CR) and between CR individuals that do possess crests and those that do not have the crest. Domestic ducks of the breed CR have allometrically larger brains than uncrested duck breeds. The crest inserts on a cushion of fat and connective tissue that is partly nourished by brain vessels via small holes in the skull. Through these holes, fat tissue may invade the brain cavity. Because the fat accumulations are sometimes hidden deep between the telencephalon, tectum, and cerebellum, they may be invisible macroscopically and, thus, give the impression of a large brain. The size of the crest, however, is not strictly correlated with fat accumulations in the brain, because 2 among 10 specimens of CR showed no fat body at all, and the investigation of 10 uncrested CR (ducks from the same genetic stock, but without the crests) also revealed fat accumulations in 6 specimens. After subtraction of the volume of the fat body, the brain volume of CR (crested and uncrested) was of equal size to that of "Hochbrutflugenten" and Pommeranian ducks, as was the volumes of most brain structures measured. Significantly smaller in CR were the olfactory bulbs, the prepiriform area, and the cerebellum, which was always situated in close proximity to the fat body in CR.

Adipose Tissue↗
PubMed2005

Broiler breeding strategies using indirect carcass measurements.

The objective of the current study was to determine the consequences of using indirect carcass measurements on the genetic response and rate of inbreeding in broiler breeding programs. In the base breeding scheme, selection candidates were evaluated based on direct carcass measurements on relatives. The possibilities of using indirect carcass measurements were investigated in alternative breeding schemes. Three alternative schemes, including indirect and own performance information for carcass traits on selection candidates, were evaluated by deterministic simulation. In the first scheme, indirect carcass traits were measured on male selection candidates. In the second scheme, indirect carcass traits were measured on male selection candidates, and direct carcass traits were measured on relatives. In the third scheme, indirect carcass traits were measured on male and female selection candidates, and direct carcass traits were measured on relatives. In the base scheme, the genetic response for breast muscle percentage (BMP) was 0.3%, and the rate of inbreeding was 0.96% per generation. In the third alternative scheme, the response for BMP increased by 66.2% compared with the base scheme, and the rate of inbreeding decreased to 0.79% per generation. The improved genetic gain resulted from increased accuracy of selection. The use of own performance information for selection candidates reduced the rate of inbreeding in alternative schemes, which is desirable for long-term selection. The accuracy of the indirect carcass measurements had consequences on the response for BMP and the rate of inbreeding. In most cases, an accuracy of 30% was sufficient to result in a higher gain for BMP and a lower rate of inbreeding as compared with the base scheme.

Animals↗