International Breeding Research Articles

Extent and Benefits of Multi-Country Progeny Testing of Young Dairy Sires

One of the current trends within the artificial insemination industry is to progeny test young dairy bulls in multiple countries. The objectives of this study were to assess the extent of multi-country progeny testing and to measure the corresponding gains in reliability of international breeding value estimates. Data of Holstein bulls that were born between July 1, 1992, and December 31, 1994, and progeny tested in countries that participate in the International Bull Evaluation Service were used in the present study, because these were the youngest bulls that had completed multi-country progeny testing before the study. Based on August 1999 international sire evaluation data, a total of 562 bulls from 10 countries were multi-country sampled for production traits during this 2.5-yr period, and 233 bulls from seven countries were multi-country sampled for type traits. The United States, Canada, the Netherlands, France, and Germany were most active in multi-country progeny testing, and Germany, New Zealand, Australia, France, and the Netherlands were the most common countries of foreign sampling. Mean reliabilities of international breeding values were calculated within each country. Means for milk yield were 0.89 for single-country sampled bulls with local progeny (i.e., progeny in the home country), 0.71 for single-country sampled bulls with no local progeny, 0.90 for multi-country sampled bulls with local progeny, and 0.78 for multi-country sampled bulls with no local progeny. Mean reliabilities for teat placement for these groups of bulls were 0.80, 0.71, 0.88, and 0.83, respectively, and means for rear udder width were 0.79, 0.60, 0.85, and 0.68, respectively. Gains in reliability in the country of foreign sampling were greatest when foreign progeny were located in countries that had low genetic correlations with the home country.

Genetic diversity of winter wheat in Shaanxi province, China, and other common wheat germplasm pools

Cultivated Chinese wheat germplasm has been a valuable genetic resourcein international plant breeding. Landraces endemic to China are a geneticresource that is distinct from other wheat germplasm. Patterns of geneticdiversity among cultivated Chinese accessions and relationship to othergermplasm pools are unknown, despite the proven value and potential novelty. Theobjective of this work was to determine the level of genetic diversity withinimproved Chinese germplasm in the context of several other wheat germplasmpools. We analyzed a set of improved accessions cultivated from the 1940s to the1990s in Shaanxi province, China, using six simple sequence repeat (SSR) primerpairs and 30 restriction fragment length polymorphism - probe enzymecombinations (RFLP-PEC) previously used to characterize 21 geographically basedgermplasm pools. Shaanxi germplasm consists of three groups based on foreignintroductions from Italy, Australia, Denmark, and Russia. There was a decreasein genetic diversity among Shaanxi accessions cultivated in the 1970s and 1980sto the 1990s, and accession classifications based on primary decade ofcultivation were found to be significantly undifferentiated. The analysis of themean genetic distance among 22 geographically based pools of germplasm suggestsseveral regions are significantly undifferentiated. A vast majority of the totalamount of variation was found within pools; therefore, pools appear to belargely differentiated based on small differences in band relative frequency andfew if any unique bands. Previous studies have identified some Chinese landracepools as morphologically and genetically unique. The Shaanxi pool does not havethe same unique morphological or genetic features, nor is it more similar to thelandrace pools than other improved germplasm pools.

History and past achievements of plant breeding

Developments in improving the world's three most important staple food crops—maize, wheat, and rice—are reviewed. A discussion of the origins and diffusion of maize and wheat and farmers' early plant breeding efforts is followed by an overview of the rise of the private sector in maize breeding, the development of international agricultural research, the Green Revolution in wheat and rice, the development of hybrid rice, and recent (1960-2000) achievements in international maize breeding research. Promising new tools for breeding improved food crops in developing countries are reviewed, including genomics and genetic engineering. Issues that will concern plant breeders—especially those focusing on the needs of developing countries—in years to come are discussed, including the rise of the private sector, intellectual property protection, and globalisation. The paper concludes with some thoughts on how plant breeding has changed in the course of the past century and must adapt to the needs of the present century.

Genetic Structure of Peruvian Populations of Phytophthora infestans

ABSTRACT Isolates of the late blight pathogen Phytophthora infestans (n = 327) from the central to southern Peruvian Andes were systematically collected in 1997 to 1999 and analyzed to determine the pathogen's population structure at its host's center of diversity. No isolates of the A2 mating type were detected. Cluster analysis of DNA fingerprinting data indicated that the collection consisted of five major groups that were interpreted to be clonal lineages. Two of the lineages (US-1 and EC-1) have been previously described, and three (PE-3, 5, and 6) are described here for the first time. Collections from three areas in the central Peruvian Andes, including two key sites used in an international potato breeding program, consisted of isolates of the EC-1 lineage, which has been reported to dominate the pathogen population in Andean countries to the north of Peru. The collections from Cusco and Puno were more diverse. More than one lineage was detected in 10 of the 20 fields sampled in Cusco. Data on virulence, metalaxyl sensitivity, and band data for allozymes, mitochondrial DNA, and ipiB1 suggested that PE-3 may have been produced through recombination events between US-1 and EC-1. Restriction fragment length polymorphism and amplified fragment length polymorphism marker data were not consistent with this hypothesis.

Weighting Factors of Sire Daughter Information in International Genetic Evaluations

International genetic evaluations of dairy bulls are currently based on national genetic evaluation results. Total number of daughters in a country is used to weight national information, but may not optimally reflect the precision of a sire's daughter contribution to international genetic evaluations. This study investigates the impact of alternative weighting factors on international evaluation results. A conventional progeny test scheme was simulated for two dairy cattle populations, with semen exchange at a fixed rate after each generation. True breeding values for both populations were generated as bivariate normal deviates. Each cow had three lactation records in one country only. After 10 generations of selection, all records were used in national breeding value prediction. National breeding values of bulls were used as input to international evaluations. Seven different weighting factors were evaluated: 1) total number of daughters; 2) total number of lactations; 3) as (one) also adjusted for finite contemporary group size; 4) as (three) also adjusted for distribution of daughters over contemporary groups; 5) effective daughter contribution considering finite contemporary group size and correlation between repeated records; 6) as (five) also considering the reliability of the daughter dam evaluation; and 7) as (five) also considering the reliability of the daughter female ancestors’ evaluations. Using the last two weighting factors yielded empirically unbiased estimates of sire variance. Using total number of daughters overestimated genetic variance by up to 7%. In general, international breeding values were marginally affected by choice of weighting factor. The effect was larger when different national evaluation models had been applied in the two countries. International reliabilities for the last two weighting factors were close to expectation, whereas using total number of daughters resulted in 1 to 4% negative bias. In practice, different countries apply a wide range of national evaluation models, and genetic ties may be weak between some populations, thereby increasing the potential effect of weighting factors on international comparisons. The weighting factor developed in this study, which considers contemporary group structure, correlation between repeated records, and reliability of dams of daughters, should replace total number of daughters in international genetic evaluations of dairy sires.

Diversity and breeding potential of poplar species in China

The genus Populus is composed of many species with an impressive variety of growth characteristics. Nevertheless, this abundant natural offering has been only partially utilized to date with the objective of promoting poplar breeding and cultivation. Following an old tradition, more or less inflexible production systems are mainly keyed to a few high-yielding P. x euramericana and P. x interamericana clones in most countries. Consequently, considerable economic failures have to be accepted repeatedly as a result of serious calamities.China ranks among the countries characterized by an exceptionally multifarious indigenous flora. Based on ample genetic variation, poplar species were able to settle in divergent habitats and to conserve the ability to survive and reproduce over long periods owing to adaptation processes. The diversity is concentrated, above all, in the subtropical mountain regions of southwest China. Comprehensive studies of the genus populus in the southern and eastern mountain chains of the Qinghai-Tibet Plateau turned out to be particularly impressive; 3 sections, 17 species and 15 varieties have been recorded and taxonomically classified there. They grow at altitudes between 1500 m and 4300 m above sea level. Many of these poplar sources are notable for their remarkable site adaptation even in harsh conditions and also for their fast and vigorous growth.Species expected to be suitable for international breeding and cultivation objectives in the near future are presented in a general way. The necessarily subjective selection is based on the state of available knowledge mainly about site requirements, environmental importance, growth characteristics, regeneration ability, silvicultural behaviour, yield estimation and wood utilization. In particular, the following species are characterized in the paper in an abridged fashion: P. cathayana, P. davidiana, P. euthratica, P. simonii, P. szechuanica, P. ussuriensis and P. yunnanensis.The potential of poplars in China is considered to be instrumental in expanding and stimulating poplar breeding activities worldwide. Measures to be specified in the paper are considered important and could be implemented on the basis of a close and confident co-operation with Chinese colleagues and institutes relevant to the subject and under the umbrella of the International Poplar Commission. Key words: poplar, tradition, calamities, China, genetic variation, promising species, characteristics, breeding priorities

The Scandinavian experience of including reproductive traits in Breeding Programmes

AbstractFemale fertility affects the culling rate as well as the direct reproduction costs and influences the calving interval and the calving season. It is therefore obvious that female fertility should be included in a Total Merit Index (TMI), which directs the genetic changes in dairy cattle selection. When the first TMI was introduced in Sweden in 1975 female fertility was included. A basic prerequisite for inclusion of fertility in the Scandinavian breeding programme was that milk recording, pedigree and AI-data were integrated in the same databases.The paper deals exclusively with the additive genetic effects on female fertility. The heritabilities of the measures used for female fertility are low, usually below 0.05. Despite this, the additive genetic variance is high as demonstrated by large differences between progeny groups. Thus, selection must be based on progeny testing of bulls on daughter groups of 100-150 daughters or more, which is the case in all the Scandinavian countries. Different procedures for calculation of daughter fertility indices are practised in Scandinavia.Research shows the importance of including measures of both the time interval from calving to insemination and a direct fertility trait such as number of inseminations or non-return rate (NR). It has also been shown that reproductive measures of different stages of life, i.e. heifer and lactating cow periods, must be considered. The genetic correlations between daughter fertility and different yield measures are negative (-0.2 to -0.4). Selection for yield without consideration of daughter fertility results in a deterioration of daughter fertility. A comparison of the flat genetic and phenotypic trends for daughter fertility along with strongly increased productivity in the SRB-breed, where Scandinavian bulls have dominated as sires of sons, and the negative trends in the SLB-breed where almost all sires of sons during a decade and a half have been imported from North America, illustrates the consequences of selection with and without consideration of daughter fertility in the sire-son path.Daughter fertility will probably remain an important trait in the future, not only in countries with seasonal milk production connected to the pasture period. As dairy cattle breeding is quite international, calculation of international breeding values for daughter fertility in the same way as is practised by INTERBULL for production and conformation seems to be an important challenge for the future.

Conservation genetics of the black rhinoceros (Diceros bicornis)

We analysed genetic variation in mitochondrial DNA (mtDNA) control region in the Diceros bicornis minor and D. b. michaelianimals at the Western Plains Zoo, which form part of an international ex-situ breeding program. Six of the nine D. b. minor animals were wild-caught from Zimbabwe during the 1990s, and our study revealed five distinct mtDNA haplotypes, and a haplotype diversity of 0.86 in the colony. Phylogenetic relationships between mtDNA haplotypes analyzed using the neighbor joining method reveal that for the small sample available, D. b. minor and D. b. michaeli are reciprocally monophyletic and represent separate ancestral lineages. Nucleotide divergence between the black and and white rhinoceros(Ceratotherium simum) was 14.0%, and nucleotide divergencebetween the D. b. minor and the D. b. michaeli subspecies was 2.6%. This suggests a divergence time for the two blackrhinoceros subspecies of between 0.93 MY and 1.3 MY.

The potato genetic resources held in trust by the International Potato Center (CIP) in Peru

Potatoes account for about half of the world's annual output of all roots and tubers, and since the early 1960s, the increase in area planted in developing countries has been higher than for any other major food crop. Annual world production currently totals 274 million tons on 18 million hectares, with China and India accounting for 22 percent of this total. In less than a generation, most of the world's potatoes will be harvested in Asia. Africa, or Latin America, where the potato is becoming an increasingly important source of food and its cultivation provides rural employment and income for the growing population. The rapid emergence of processing facilities for the fast food industry, and the indirect influence of improved rice and wheat irrigation systems have also contributed to the expansion of potato production in Asia. The demand is strongest for processing quality potatoes that supply the fast food chains in large urban concentrations where processed potato products fetch top prices. Such increasing demand is putting strong pressure on national and international breeding institutions to produce high quality processing varieties well adapted to the wide array of agro-ecological conditions, in South East Asia in particular. The lack of adequate seed systems in this region is the single most important impediment to the expansion of the cultivation of the crop. Unfavourable agro-ecological conditions interfere with the production of high quality seed in most Asian potato growing areas, and the availability of high quality seed of the right quantity at the right time remains the most consequential bottleneck to efficient potato production. The seed issue is also the principal problem of potato cultivation in the traditional potato growing areas of Central and Eastern Europe. A review of “the development of integrated systems for large scale propagation of elite plants using in vitro techniques” with specific focus on “potato seed production by tissue culture” is therefore very timely. It provides a platform for analysis and discussion of solutions for some of the most common seed problems facing the potato industry in many parts of the word. All efforts to improve the potato crop and to solve the associated seed problems begin with the right choice and use of the available genetic resources. Resistance to certain pests and diseases has a direct bearing on the success of a seed program. Multiple virus resistance, in particular, would ensure a halt to seed degeneration caused by an accumulation of viruses and thus greatly prolong the ability of seed producers and ware potato growing farmers to grow their crops at great economic benefit. This paper will therefore deal with the current status of the World Potato Collection held in trust by the International Potato Center (CIP) in Peru by presenting up-to-date information on its classification, phytosanitary status and availability of the genetic material and its evaluation data to the breeders worldwide.

Approaches for breaching yield stagnation in wheat

This paper outlines the breeding objectives, methodology, and genetic gains of the international wheat breeding program of the International Maize and Wheat Improvement Center (CIMMYT) based in Mexico. The historical analysis of yield gains asserts that wise use of genetic diversity has been paramount in raising the yield ceiling and expanding genetic variability. Data is provided to support a philosophical view that yield potential per se should be combined with both abiotic and biotic tolerances in the breeding of future cultivars. The erosion of high yield potential should be avoided at all costs through a protective shield of wide-spectrum disease resistance genes.Key words: yield potential, shuttle breeding, Aegilops squarrosa.

Genotype by Environment Interaction and International Breeding Programmes

This paper addresses the issue of genotype by environment (G × E) interaction in relation to the distribution of germplasm from international to national breeding programmes. Theoretical aspects of G × E interaction and of the selection versus the test environment are reviewed. The importance of specific adaptation to maximize yield and yield stability under stress conditions is highlighted in barley and lentil. We conclude that repeated cycles of selection at a few sites have a high probability of reducing the frequency of genotypes specifically adapted to environmental and/or agronomic conditions not represented at those sites. Therefore a wider and earlier devolution of the selection work done by International Agricultural Research Centres (IARCs) to plant breeders in national programmes will increase the chances of exploiting positive G × E interactions. It will also address the needs of small, resource-poor, subsistence farmers and reduce the danger of narrowing genetic diversity within crops and regions. This is an efficient way of making breeding programmes in less developed countries more self-reliant, which is a major objective of International Agricultural Research Centres.Programas internacionales de reproducción

Transgressive segregation for resistance to Pyrenophora teres in barley

Populations of F1, F2, F1× parent 1 (BC1), F1× parent 2 (BC2), and F3 resulting from two crosses between four susceptible varieties of barley used in national and international breeding programmes were tested at the seedling stage for their resistance to an isolate of Pyrenophora teres which is virulent to the parental varieties. Infection type, average lesion size, and number of lesions per unit leaf area were used to assess disease reaction. In the two crosses, F2 and especially F3 generations (produced by self pollination of selected resistant F2 plants) showed more resistance expressed by infection type and average lesion size than either parent. The frequency distributions of F2 and F3 generations derived from these crosses were continuous and showed transgressive segregation for resistance. The results indicated that the four cultivars used in this study possessed additive genes for resistance to P. teres. Thus useful resistance could be obtained following crossing of susceptible cultivars and selection in succeeding generations.

Forests to fields restoring tropical lands to agriculture

In discussing land use in tropical forest regions, there is an emphasis on the following topics: the need for the expansion of cropping areas, the precedent for use of the tropical forest for cropping based on past use patterns, the pressure from conservationists against cropping, debunking the mythology that forests are "natural" and refuting the claims that forest clearance is not reversible, the archeological evidence of past forest use for agricultural purposes, abandonment of tropical land to forest, and rotation of forest and field. The assumption is that the way to stop food importation is to increase crop production in the tropics. Crop production can be increased through 1) land intensification or clearing new land, 2) output per unit of land increases, or 3) reallocation to agriculture land previously cleared and overgrown with tropical forest. "Temporary" reuse of land, which reverted back to tropical forest, is recommended. This reuse would ease population pressure, and benefit bioconservation, while populations stabilize and further progress is made in international plant breeding. The land would eventually be returned to a forest state. Conservation of tropical forest areas should be accomplished, after an assessment has been made of its former uses. Primary forests need to identified and conversion to farming ceased. Research needs to be directed to understanding the process of past forest regeneration, and to devising cropping systems with longterm viability. The green revolution is unsuitable for traditional cropping systems, is contrary to demands of international funding agencies for sustainability, and is not affordable by most poor farmers. Only .48 million sq. km of closed forest loss was in tropical rainforests; 6.53 million sq. km was lost from temperate forests cleared for intensive small-scale peasant farming. The use of tropical forest land for farming has some benefits; crops in the wetter tropics are perennial, which would "reduce seasonal soil tillage, increase nutrient cycling, and remove a lower proportion of biomass." Water availability would not be a problem. Low soil nutrient levels could be increased with cutting and burning or fertilizer. The key is proper and careful management, particularly under intensive cropping systems such as rice production or extensive long fallow shifting cultivation.

Generation Mean Analysis of Inheritance of Resistance to Pyrenophora teres in Barley

AbstractF1, F2, Fl × parentl (BC1), and Fl × parent2 (BC2) generations resulting from four crosses among seven cultivars of barley used in national and international breeding programmes were tested at the seedling stage for their resistance to a mixture of five isolates of Pyrenophora teres. Four methods were used to assess disease resistance: infection type (IT), average lesion size (ALS), number of lesions per unit leaf area (NL) and percent leaf area infected (PLAI). Gene actions were estimated by generation mean analysis on each of the four crosses and on each of the evaluation methods. Significant additive and additive × additive epistatic effects were found. Infection type and percent leaf area infected were found to be highly correlated in all four crosses. These results suggest that barley breeders could improve the level of resistance to P. teres by making appropriate crosses between highly susceptible barley cultivars.

International evaluation of Holstein-Friesian dairy sires from three countries

Official 1985 genetic evaluations of Holstein-Friesian dairy sires for milk yield, fat yield and fat percentage from Canada and the U.S.A. were pooled with unofficial 1985 genetic evaluations of sires from Italy in order to obtain international evaluations of sires for these three countries. There were 1766 sires from Canada, 9746 from the U.S.A. and 4191 from Italy with at least 20 daughters or 5 effective daughters each. The linear model for describing a sire's daughter average, free of all non-genetic fixed effects, included the country of proof, the country of origin and year of birth, sires within country of origin and year of birth and all additive genetic relationships among bulls. Daughter averages were approximated by de-regressing sire proofs and accounting for year of birth within country. Differences in country of proof solutions reflect differences in genetic bases of evaluation; the Italian minus the Canadian and the U.S. solutions were, respectively, 334 and 565 kg for milk yield, 14.4 and 19.6 kg for fat yield, and 0.05 and -0.01% for fat percentage. Between 1955–1959 and 1960–1964, there was very little genetic progress in all countries. Genetic change in sires born between 1965–1969 and 1975–1979 were 121, 198 and 87 kg for milk yield, 4.6, 6.0 and 2.4 kg for fat yield, and 0.01, -0.02 and -0.02% for fat percentage in Canada, the U.S.A. and Italy, respectively. Sires imported to Canada, the U.S.A. and Italy had average evaluations different from those of local sires within countries by 126, -211 and 45 kg for milk yield, 4.2, -6.4 and 2.0 kg for fat yield, and -0.01, 0.02 and 0.01% for fat percentage, respectively. The estimation of international sire breeding values on a routine basis was shown to be feasible, but many problems still remain to be solved. Besides the need for sufficient links between countries, the primary problem is that of accounting for non-random mating of sires within each country.

A methodology for evaluating a location as a selection site for an international plant breeding program

A method for comparing locations as selection sites based upon their abilities to predict yield and disease reaction over a target region is proposed. The probability of coincidence in selection for a site is defined as the probability for a line selected at the site to be selected at other sites within the region. The probability of divergence in rejection is defined as that associated with regional selection of a line given that is discarded by the site where selection is being conducted. The ideal selection site would maximize the probability of coincidence in selection and minimize the probability of divergence in rejection. The method is illustrated using a set of data from the rice yield nurseries of the International Rice Testing Program for Latin America planted under the rainfed conditions of Central America and Mexico during the period 1978–1984. Five locations were compared for their predictive ability in selecting for the rainfed rice growing region, based on yield and disease reaction. Selection for yield was defined as performance superior to the best check in each location. Selection for disease reaction was based on an index derived from the Standard Evaluation System for Rice for diseases of regional importance. Locations varies 10–15 percent in their selection coincidence with the region for both yield and disease selection criteria applied independently.

Reproductive physiology of the clouded leopard: I. Electroejaculates contain high proportions of pleiomorphic spermatozoa throughout the year.

Ejaculates were analyzed from clouded leopards (Neofelis nebulosa) subjected to a regimented anesthesia/electroejaculation protocol. Group I males (n = 4), maintained individually in an environment with natural fluctuations in photoperiod, were electroejaculated on the same day at monthly intervals (January-December). Group II clouded leopards (n = 8), maintained in random zoo populations throughout the U.S., were evaluated on a single occasion. Phase contrast and electron microscopy indicated a high proportion of structurally abnormal spermatozoa in seminal fluid (Group I range, 14.8-78.9%; Group II range, 32.3-93.0%), the predominant deformity being a tightly coiled flagellum. Semen quality, including spermatozoal concentration and the incidence of abnormal sperm forms, varied (p less than 0.05) among males. Evaluating the numbers of motile spermatozoa/ejaculate (MS/E) among individual males from Group I on a monthly basis suggested a seasonal influence; gradually increasing MS/E values with peaks in June and July were observed in three of four animals. A simultaneous analysis of international breeding records for captive female clouded leopards demonstrated that 46.2% of parturitions occurred in March and April, indicating that most estrual periods occurred from late December through February. These data suggest that a physiological asymmetry may exist in peak reproductive performance between the male and female clouded leopard, perhaps as a result of differing adaptations to the captive environment. Motile spermatozoa can be recovered throughout the year using electroejaculation and, when used over time, a standardized procedure can determine a hierarchy of seminal quality among males of unknown reproductive potential. The relatively high proportions of structurally abnormal spermatozoa in the ejaculates of the clouded leopard may be related to a low degree of genetic variation within the species and/or hyperadrenal activity in captive populations.

Effect of iron-saecharate infections of finnish horse: P. Hartikka, M. Dahlban and H. Westermarck: Nord Vet Med 35 251–256 (1983)

Trotting racing is one of the most popular horse sports in Europe. The Spanish Trotter Horse (STH) can be considered as a composite of the main World trotter populations. This is because the Spanish Trotter Breed often imports breeding stock from the main Trotter Horse Breeds; mainly American and French Trotters. The Breeding Program of the STH includes earnings, placing and time traits as main selection criteria.The main aim of this paper is to estimate the genetic parameters in the STH population and to show the characteristics of the STH population as a connecting population in order to include it in an international breeding evaluation for trotting ability. For this purpose, we used 285,538 racing records from 5086 horses during a 16 year period. All the known ancestors of the recorded animals were included in the pedigree file (10,940 horses), making sure that at least four generations for foreign horses were included. A multivariate Animal Model was developed using four different performance traits: annual earnings (log transformed), percentage of first placing in a year (square root transformed), time per kilometer and best racing time per hippodrome and type of start.Genetic connectedness of performance data was adequate. The estimates of heritability ranged between 0.14 ± 0.017 for the percentage of first placing and 0.29 ± 0.018 for the best racing time per hippodrome and type of start. The other traits had a medium magnitude of heritability, and were 0.27 ± 0.018 for the annual earnings and 0.28 ± 0.017 for the annual earnings and the time per kilometer . All these values were within the range with those reported by authors for other trotter populations. The repeatability values had ranged between 0.31 for the percentage of first placing and 0.65 for the time per kilometer. The genetic correlations have medium-high magnitude, ranging between 0.61 ± 0.044 and 0.99 ± 0.005. There was a negative correlation between time traits and the other analyzed traits, as was expected because a decrease in the time traits is always related to an improvement in the performance results in races.Given its own genetic composition, the population of trotter horses in Spain could be considered as a connecting population in order to develop an international genetic evaluation. Therefore, these parameters could be taken into account for an international genetic evaluation of trotter horses.

The Interrelationship of the Egg Records of Various Periods During the First and Second year of the White Leghorn Fowl

I. IntroductionThe primary purpose of this paper is to consider the interrelationship of the egg records of various periods during the second laying year of the White Leghorn fowl. It is, therefore, a continuation of earlier investigations in this general field, which have, of necessity, been limited to a consideration of the relationship between the periods of the first or pullet year (Harris and others, 1917–1921).While our primary purpose has been the investigation of the correlations for the second laying year, these interrelationships can be fully understood only when considered in comparison with the like coefficients for the first year.Fortunately the extensive data of the Vineland International Egg Laying and Breeding Contest permits the consideration of the complete first and second year record of 443 individual White Leghorn birds. Our problem is, therefore, to consider all of the more important correlations between the egg records of .

Expected Egg Production

Prof. Philips in the previous paper has presented a very interesting problem which the writer believes could, to advantage, be extensively discussed in the columns of our Journal. The time is here when we must know more about cost accounting factors relative to poultry keeping. An effort is already being made in many states to compile and gather reliable data along these lines. The Poultry Department at New Brunswick has a slight contribution which can be made to this subject at this time in the form of a comparison of the actual and expected egg production from the commercial flocks of the State, together with results of the work at the Vineland International Egg Laying and Breeding Contest. The egg production given below from the report of the surveys of 150 commercial poultry farms in New Jersey, includes both hen and pullet flocks, and represents a distribution of approximately two-thirds …