Negative Phenotypic Correlations Research Articles

Character association and inheritance studies of different sorghum genotypes for fodder yield and quality under irrigated and rainfed conditions

Cyanide poisoning is the major problem in sorghum fodder. This poisoning results in livestock mortality and causes economic loss to the people. Some work have been reported on quantity but little work has been focused on quality especially the cyanide content in sorghum fodder in Pakistan. Inheritance mechanism for some fodder yield and quality traits were studied among 25 sorghum genotypes under irrigated and rainfed conditions. Highly significant genotypic as well as genotype x location differences were observed for all the characters studied. Highest genotypic and phenotypic variances were observed for plant height, fresh weight plant-1, green fodder yield and total cyanide content. Green fodder yield, dry matter yield, fresh weight plant-1, dry weight plant-1 and total cyanide content depicted high heritability estimates along with high expected genetic advance. There were strong positive genotypic and phenotypic correlations between green fodder yield and number of tillers plant-1 stem thickness, fresh weight plant-1, dry weight plant-1 and dry matter yield. Strong negative genotypic and phenotypic correlations were observed between total cyanide content and number of tillers plant-1, stem thickness, fresh weight plant-1, dry weight plant-1 and green fodder yield. The present study indicates that the indirect selection and simultaneous improvement in sorghum fodder yield as well as quality is feasible because of significant relationship among traits. Key words: Correlation-fodder yield-genetic advance-heritability-hydrocyanic acid, quality traits-Sorghum bicolor.

Strong Genetic Control of High Wood Specific Gravity in Young Progenies ofPinus brutia: Potential of Early Selection for Industrial Plantations

AbstractTo increase quality and amount of wood production in Turkish red pine (Pinus brutiaTen.), genetic control of wood specific gravity (WSG), tracheid length and growth traits was investigated in Ceyhan1A progeny trial by evaluating 168 families originated from six clonal Turkish red pine seed orchards. Wood samples were taken by destructive sampling during the rouging of this trial at the age of seven. Differences among the 168 families for mean WSG was large (ranged from 0.35 to 0.62), as indicated by high individual (0.42±0.07) and family mean (0.55±0.03) heritabilities. Family differences and high heritabilities were also observed for all growth traits and tracheid length. Genetic correlations between WSG and growth traits were insignificant (near zero), while low and insignificant negative phenotypic correlations among the same traits were also observed. Predicted genetic gain for single trait selection at age of seven was low for WSG (0.37%), but substantial for stem volume (8.4%) in phenotypic seed orchards. However, the first generation clonal seed orchards consisting of the best 30 clones yielded higher genetic gains (5.2% for WSG and 35% for stem volume). These preliminary results suggest that selection for wood characteristics and growth traits in Turkish pine could be practiced at early ages for short rotation (about 30 years) in industrial plantations.

Genetic and Economic Analysis for the Relationship between Udder Health and Milk Production Traits in Friesian Cows

A total of 4,752 monthly lactation records of Friesian cows during the period from 2000 to 2005 were used to estimate genetic parameters and to determine the effect of udder health on milk production traits. Three milk production traits were studied: 305- day milk yield (305-dMY), 305-day fat yield (305-dFY) and 305-day protein yield (305-dPY). Four udder health traits were studied: somatic cell count (SCC), mastitis (MAST), udder health status (UDHS) with 10 categories and udder quarter infection (UDQI) with 7 categories. Mixed model least square analysis was used to estimate the fixed effects of month and year of calving and parity (P) on different studied traits. Sire and dam within sire were included in the model as random effects. Data were analyzed using Multi-trait Derivative Free Restricted Maximum Likelihood methodology (MTDFREML) to estimate genetic parameters. Unadjusted means of 305-dMY, 305-dFY, 305-dPY and SCC were 3,936, 121, 90 kg and 453,000 cells/ml, respectively. Increasing SCC from 300,000 to 2,000,000 cells/ml increased UDQI from 5.51 to 23.2%. Losses in monthly and lactationally milk yields per cow ranged from 17 to 93 and from 135 to 991 kg, respectively. The corresponding losses in monthly and lactationally milk yields return per cow at the same level of SCC ranged from 29.8 to 163 and from 236 to 1,734 Egyptian pounds, respectively. Heritability estimates of 305-dMY, 305-dFY, 305-dPY, SCC, MAST, UDHS, UDQI were 0.31±0.4, 0.33±0.03, 0.35±0.05, 0.23±0.02, 0.14±0.02, 0.13±0.03, and 0.09±0.01, respectively. All milk production traits showed slightly unfavorable negative phenotypic and genetic correlations with SCC, MAST, UDHS and UDQI. There were positive and high genetic correlations between SCC and each of MAST (0.85±0.7), UDHS (0.87±0.10) and UDQI (0.77±0.06) and between MAST and each of UDHS (0.91±0.11) and UDQI (0.83±0.07). It could be concluded that the economic losses from mastitis and high SCC are considerable. The high genetic correlation between SCC and clinical mastitis (CM) suggest that the selection for lower SCC would help to reduce or eliminate the undesirable correlated responses of clinical mastitis associated with selection for increasing milk yield. Additionally, it is recommended also that if direct information on under health traits

A Genetically Informed Study of the Covariation Between the CBCL/6-18 DSM-Oriented Problem Scales and the Competence Scales

In 398 twin pairs belonging to the population-based Italian Registry, we investigated by the monozygotic twin intrapair differences model and bivariate designs whether the phenotypic correlations between CBCL/6-18 problem behaviours and competencies could better be accounted for by direct, causal effects, or by the presence of latent etiological factors, acting simultaneously as elements of risk/protection for psychopathology and competencies. All zero-order correlations between six CBCL DSM-oriented scales (DOS) and three competence scales (CS) were negative and small-to-moderate. After implementing multiple regressions we found robust enough prediction only for ADH DOS on school CS, and for anxiety DOS on social CS. Results from the intrapair differences model indicated shared elements of liability, rather than direct causation, as more likely explanations for the negative phenotypic correlations between these emotional/behavioural problem and competencies scores. Bivariate analyses indicated shared genetic factors that influence simultaneously the emotional/behavioural problems and the competencies domains as the best explanations for the phenotypic covariations between DOS and CS.

Gene action of canopy temperature in bread wheat under diverse environments

While canopy temperature (CT) shows a strong and reliable association with yield under drought and heat stress and is used in wheat breeding to select for yield, little is known of its genetic control. The objective of this study was to determine the gene action controlling CT in five wheat populations grown in diverse environments (heat, drought, and well-irrigated conditions). CT showed negative phenotypic correlations with grain yield under drought and well-irrigated environments. Additive x additive effects were most prevalent and significant for all crosses and environments. Dominance and dominance x dominance gene actions were also found, though the significance and direction was specific for each environment and genotypic cross. The use of CT as a selection criterion to improve tolerance to drought was supported by its significant association with grain yield and the genotype differences observed between cultivars. Our results indicated that genetic gains for CT in wheat could be achieved through conventional breeding. However, given some dominance and epistatic effects, it would be necessary to delay the selection process until the frequency of heterozygous loci within families is reduced.

Estimates of genetic and phenotypic parameters for production, haematological and gastrointestinal nematode-associated traits in Australian Angora goats

Genetic parameters for liveweight (LWT), greasy fleece weight (GFW), mean fibre diameter (MFD), standard deviation of MFD (MFD-s.d.), mean fibre curvature (CURVE) percentage of medullated (%MED) and kemp (%KEMP) fibres, faecal worm egg count (WEC), packed cell volume (PCV), mean corpuscular volume (MCV) mean corpuscular haemoglobin content (MCHC), circulating anti-nematode IgG (IgG) and counts of circulating eosinophils (EOS), lymphocytes (LYM), neutrophils (NEU), basophils (BASO) and monocytes (MONO) up to 18 months of age were estimated in Australian Angora goats (608 animals, 14 sires 3 years of birth). Measurements were made during a period of natural parasite challenge up to 5 months of age, or following artificial challenge with 10 000 infective larvae of Trichostrongylus colubriformis at 5.25 months of age. Year of birth had a significant impact on production and parasite-associated traits at all ages studied. Sex had a marked effect on production and erythrocyte traits. Birth type had no effect on any traits in animals older than 6 months. Maternal effects were not significant except for LWT at 3, 5 and 6 months and for IgG at 3 months. Most production traits were highly (LWT, GFW, MFD, %MED) or moderately (CURVE, MFD-s.d.) heritable (range 0.17–0.59) with only %KEMP having a low heritability (0.02–0.14). The heritability estimates (±s.e.) for CURVE are novel for goats and ranged from 0.18 ± 0.09 at first shearing to 0.44 ± 0.14 at third shearing. Heritability estimates were low for WEC (0.02–0.16) and for specific IgG during natural infection (0.14–0.15) but higher for IgG following artificial challenge with T. colubriformis (0.42 ± 0.13). Of the haematological variables NEU and all red cell traits were highly heritable (0.45–0.71), LYM and MONO were moderately to highly heritable (0.31–0.55), and EOS was weakly to moderately heritable (0.06–0.28). Strong phenotypic correlations existed between production traits. MFD was positively correlated with GFW and negatively correlated with CURVE, indicating that finer fibres have a higher crimp or wave count. WEC had consistent negative phenotypic correlations with PCV, LYM and EOS, and positive correlations with NEU. Correlations with IgG were positive up to 5 months and negative thereafter. Phenotypic correlations between WEC and LWT as well as with GFW and MFD were negative. Heritability estimates for production traits were generally consistent with other studies. Haematological and fibre curvature findings are completely novel for Angora goats. Estimates of heritability for WEC fell in mid range of published findings for other goat breeds, and these results suggest that there is some scope for breeding for worm resistance in Angoras but the response is likely to be slow.

GENETIC AND ECONOMIC ANALYSIS FOR THE RELATIONSHIP BETWEEN UDDER HEALTH AND MILK PRODUCTION TRAITS IN FRIESIAN COWS

A total of 4,752 monthly lactation records of Friesian cows during the period from 2000 to 2005 were used to estimate genetic parameters and to determine the effect of udder health on milk production traits. Three milk production traits were studied: 305- day milk yield (305-dMY), 305-day fat yield (305-dFY) and 305-day protein yield (305-dPY). Four udder health traits were studied: somatic cell count (SCC), mastitis (MAST), udder health status (UDHS) with 10 categories and udder quarter infection (UDQI) with 7 categories. Mixed model least square analysis was used to estimate the fixed effects of month and year of calving and parity (P) on different studied traits. Sire and dam within sire were included in the model as random effects. Data were analyzed using Multi-trait Derivative Free Restricted Maximum Likelihood methodology (MTDFREML) to estimate genetic parameters. Unadjusted means of 305-dMY, 305-dFY, 305-dPY and SCC were 3,936, 121, 90 kg and 453,000 cells/ml, respectively. Increasing SCC from 300,000 to 2,000,000 cells/ml increased UDQI from 5.51 to 23.2%. Losses in monthly and lactationally milk yields per cow ranged from 17 to 93 and from 135 to 991 kg, respectively. The corresponding losses in monthly and lactationally milk yields return per cow at the same level of SCC ranged from 29.8 to 163 and from 236 to 1,734 Egyptian pounds, respectively. Heritability estimates of 305-dMY, 305-dFY, 305-dPY, SCC, MAST, UDHS, UDQI were 0.31±0.4, 0.33±0.03, 0.35±0.05, 0.23±0.02, 0.14±0.02, 0.13±0.03, and 0.09±0.01, respectively. All milk production traits showed slightly unfavorable negative phenotypic and genetic correlations with SCC, MAST, UDHS and UDQI. There were positive and high genetic correlations between SCC and each of MAST (0.85±0.7), UDHS (0.87±0.10) and UDQI (0.77±0.06) and between MAST and each of UDHS (0.91±0.11) and UDQI (0.83±0.07). It could be concluded that the economic losses from mastitis and high SCC are considerable. The high genetic correlation between SCC and clinical mastitis (CM) suggest that the selection for lower SCC would help to reduce or eliminate the undesirable correlated responses of clinical mastitis associated with selection for increasing milk yield. Additionally, it is recommended also that if direct information on under health traits

Heritability of shoot die-back and root biomass in sixteen Pterocarpus angolensis (Fabaceae) half-sib families from Malawi, Namibia and Zambia

The experiment was conducted to ascertain narrow-sense heritability (h 2) and the family-within-provenance variation in shoot die-back, taproot length and root biomass of half-sib Pterocarpus angolensis families from Malawi, Namibia and Zambia. Provenances differed significantly in shoot die-back for both shoot die-back seasons. A within provenance family effect was not significant in the first shoot die-back season but was significant in the second shoot die-back season. An increase in proportion of seedlings dying back, to 91%, for a Malawi family was observed in the second shoot die-back season. Provenance and within provenance family effects may be due to latitudinal differences between the provenances. The h 2 of shoot die-back was 0.07 (SE = 0.07) in the first shoot die-back season and 0.42 (SE = 0.27) in the second shoot die-back season. Narrow-sense heritability for root biomass was 0.81 (SE = 0.45). The h 2 for the second die-back season and root biomass suggest the traits are heritable. Random selection of individual families for assessing shoot die-back is important since this trait is only restricted to seedlings and saplings and not mature trees. Within provenance family effects for root biomass were significant, indicating differences between families. Two families from the most northerly provenances of Phalombe and Skull Rock in Malawi were significantly different from other southern families. Non-significant phenotypic correlation between shoot die-back and root biomass shows that shoot die-back is not likely to be determined by root size nor taproot depth. Although a non-significant negative phenotypic correlation (–0.15) between the second shoot die-back season and root biomass was obtained, a family from Malawi that had the highest mean shoot die-back in the second shoot die-back season had the smallest root biomass. Half-sib families with post shoot die-back growth potential, in the first shoot die-back season, are likely to have a better chance of post shoot die-back growth later.

Comportamento agronômico e qualidade culinária de feijão-caupi no Vale do São Francisco

Foi avaliado o comportamento de 64 linhagens e quatro cultivares de feijão-caupi (Vigna unguiculata (L.) Walp.), em dois experimentos de diferentes densidades populacionais, em diversos ambientes do Vale do São Francisco em 2004 e 2005, em regime irrigado ou de sequeiro, visando à recomendação de cultivares para a região. Os experimentos foram conduzidos em blocos ao caso, com três repetições, nas densidades de 100.000 e 200.000 plantas/ha, tendo sido analisados a produtividade, parâmetros genéticos, tolerância as algumas viroses, peso de 100 grãos, dias para a maturação e variáveis de qualidade tecnológica dos grãos. Observou-se forte interação genótipo x ambiente para as variáveis analisadas. Os valores médios observadas no experimento sob irrigação superaram aqueles do experimento de sequeiro em mais que o dobro, nas duas densidades populacionais. Algumas linhagens não apresentaram sintomas de virose, sendo que as cultivares BR 17 Gurguéia e Canapu foram as mais suscetíveis. O peso médio de 100 grãos foi em torno de 20 g nas duas densidades de plantio. O 'Canapu' apresentou o maior valor de embebição de água antes do cozimento, diferindo significativamente dos demais tratamentos. O valor de embebição de água após o cozimento apresentou correlação negativa significativa com a taxa de expansão volumétrica dos grãos após o cozimento. A linhagem PC 95-05-12-2-2 que apresentou valores próximos de 1,0 (sem sintomas) para as viroses, produtividade superior à média, adaptabilidade de grãos foi recomendada para a região com o nome de 'BRS Pujante'.

Genotype x environment interaction and selection foryield and related traits in soybean

Fifteen genotypes of soybeans (Glycine max L.Merr.) were grown in three locations of Ibadan, Abeokuta and Ogbomoso during the late planting season of 2001, 2002 and 2003. Data on yield and yield traits were subjected to combined analysis of variance. There were variations in the years of production as the relative performance of the genotypes with respect to all the traits were significant under the genotype x year (Gen. x yr) effect. However, days to maturity, number of pods per plant and number of branches per plant were significant under the genotype x location (Gen. x loc.), and the third order interaction effect of Gen. x loc. x yr. Branch number per plant gave negative but significant phenotypic correlation with number of seeds per pod and weight of seeds while its correlation with seed yield was positive in Ogbomoso and Abeokuta locations. Significant genotypic correlation were observed between number of seeds per pod with seed weight and seed yield for Ibadan and Ogbomoso locations though its correlation with seed weight in Ogbomoso location was negative. The significant genotypic correlation of days to maturity with pod number and branch number ensures that these traits would be successfully selected for in yield improvement of soybean for Abeokuta and Ogbomoso locations. Number of seeds per pod and days to maturity with high heritability estimates and significant genotypic correlations can be reliably selected for when soybean improvement is targeted for Ibadan and Ogbomoso specific locations. Keywords: Correlation; environment; genotype; heritability; locations; traits Moor Journal of Agricultural Research Vol. 6 (1&2) 2005 pp. 81-86

Pig peripheral blood mononuclear leucocyte subsets are heritable and genetically correlated with performance

Indicator traits used to select pigs for increased resistance to infection or improved health must be heritable and, preferably, be associated with improved performance. We estimated the heritability of a range of immune traits and their genetic and phenotypic correlations with growth performance. We measured immune traits on 589 pigs and performance on 1941 pigs from six farms, three of which were classified as ‘high health status’ (i.e. specific pathogen-free) and three were of lower health status. All pigs were apparently healthy. Immune traits were total white blood cells (WBC), and peripheral blood mononuclear leucocyte (PBML) subsets positive for CD4, CD8α, gamma delta (γδ) T cell receptor, CD11R1 (natural killer cell marker), B cell and monocyte markers at the start and the end of standard growth performance tests. At both time points, all immune traits were moderately to highly heritable except for CD8α+ cells. At end of test, heritability estimates (h2) (±s.e.) were 0.18 (±0.11) for total WBC count. For PBML subset proportions, the heritabilities were 0.52 (±0.14) for γδ TCR+ cells, 0.62 (±0.14) for CD4+ cells, 0.44 (±0.14) for CD11R1+ cells, 0.58 (±0.14) for B cells and 0.59 (±0.14) for monocytes. Farm health status affected the heritabilities for WBC, being substantially higher on lower health status farms, but did not have consistent effects on heritabilities for the PBML subsets. There were significant negative genetic correlations between numbers and proportions of various PBML subsets and performance, at both start and end of test. In particular, the proportion of PBML cells that were CD11R1+ cells, at end of test, was strongly correlated with daily gain (rg = −0.72; P < 0.01). There were also weaker but significant negative phenotypic correlations between PBML subsets measured at end of test and performance, for γδ+ T cells, CD8α+, CD11R1+ cells, B cells or monocytes. Phenotypic correlations with daily gain were generally lower at the start of test than at the end of test. These results show that most of the major pig PBML subsets are heritable, and that systemic levels of several of these PBML subsets are genetically negatively correlated with performance. This approach provides a basis for using immune trait markers when selecting boars that can produce higher-performing progeny.

Genetic resistance to growth of Lucilia cuprina larvae in Merino sheep

Cutaneous myiasis (fly strike), caused by Lucilia cuprina, is a major ectoparasitic infection of sheep. Previous research has identified contributions of body conformation, wool characteristics and resistance to bacterial dermatoses to resistance to fly strike. This paper investigates whether genetic variation occurs amongst sheep in growth of larvae on skin. Mixed sex Merino sheep in 27 half-sibling groups were challenged with freshly hatched Lucilia cuprina larvae, and survival and growth of larvae were measured after 50 h. Growth but not survival of larvae had moderate heritability (0.29 ± 0.22), comparable to that seen for resistance to nematode parasites in sheep. Phenotypic correlations between resistance to larval growth and wool traits, skin wheal response to intradermal injection of larval excretory secretory products and resistance to internal parasites were negligible; however, there was a significant negative phenotypic correlation with fleece rot score after exposure of sheep to simulated rain at a time independent to that of measurement of larval growth. Larval growth was negatively correlated with peripheral blood eosinophil numbers measured either before or after larval challenge. In addition, larval growth in vitro on serum collected from challenged sheep was moderately associated with larval growth in vivo. A search for quantitative trait loci (QTL) for larval survival and growth was conducted in data from 94 half-sibling progeny of a Merino × Romney sire backcrossed to Merino ewes. Potential QTL for larval growth were identified on chromosome 11 and for larval survival on chromosome 18, although phenotyping greater numbers of sheep and a higher marker density on these chromosomes is necessary to confirm the result. We conclude that this study has identified a novel level of resistance of Merino sheep to growth of L. cuprina larvae that may be mediated in part through actions of anti-larval factors in serum and eosinophils. Further studies are required to establish the impact of growth retardation on the severity of systemic responses of sheep to fly strike and on the biology of adult flies.

Genetic control of intra-ring wood density variation in hybrid larch (Larix gmelinii var. japonica × L. kaempferi) F1

Genetic parameters for various wood density traits were estimated in 29-year-old trees of 18 full-sib families of hybrid larch (Larix gmelinii var. japonica × Larix kaempferi) F1. Intra-ring density variation (IDV) was also evaluated using a model that expresses the pattern curve from earlywood to latewood as a power function. A high IDV indicates an abrupt change in wood density from earlywood to latewood. The ring width and wood density traits of individual rings were determined by X-ray densitometry. Overall wood density (RD) was shown to increase with increasing ring number, ranging from 0.42–0.59 g/cm3, whereas IDV of individual rings decreased gradually from pith outwards. Estimates of individual tree narrow-sense heritability of RD and IDV were 0.66 and 0.67, respectively. IDV showed negative genetic and phenotypic correlations with RD (r g = −0.99, r p = −0.72). The predicted genetic gains in latewood proportion and IDV were higher than that of RD. These results suggest that the intra-ring density variation is under moderate genetic control equivalent to wood density. The trend of increasing wood density from earlywood to latewood was associated with changes in both tracheid diameter and cell wall thickness.

Estimations of repeatability and heritability of egg albumen antimicrobial activity and of lysozyme and ovotransferrin concentrations

1. The repeatability and heritability of growth inhibition by egg albumen of two major pathogenic bacteria, a Gram-negative (Salmonella Enteritidis) and a Gram-positive (Staphyloccocus aureus) and of two antimicrobial albumen proteins, lysozyme and ovotransferrin, were estimated in commercial pedigree hens. 2. Repeatability was evaluated in 100 egg-type hens at the beginning, middle and end of the laying cycle on eggs collected for 3 weeks. Heritabilities were estimated at 36 to 40 weeks of age on 400 pedigree hens (2 eggs/hen), which were the offspring of 25 sires each mated with 4 dams. Ovotransferrin and lysozyme were quantified by ELISA. Salmonella Enteritidis (S.E.) and Staphyloccocus aureus (S.A.) were inoculated into a sample of sterilised albumen and enumerated after incubation. 3. Total protein content in albumen decreased with age of laying hens, whereas there were increases in lysozyme or ovotransferrin concentrations and in the bacteriostatic effect of albumen. 4. Repeatability for bacterial growth in albumen ranged from 0·29 to 0·39 for the number of S.E. (log cfu/ml) one day post inoculation (p.i.) but was lower and more variable at 5 d p.i. or for S.A. number. It ranged from 0·27 to 0·38 for S.E. and S.A. number at the mid period of the laying cycle. Repeatabilities were low and variable for total egg albumen protein or lysozyme and ovotranferrin concentrations (0 to 0·22). 5. Negative phenotypic correlations were observed between lysozyme concentrations and S.E. number but that between lysozyme and S.A. number was not significant. 6. Heritabilities were low (0·01 to 0·09) for protein traits. They were 0·11 for S.A. number and 0·16 for S.E. number one day p.i. 7. It appears to be more efficient to select on global bacterial growth than on specific antimicrobial proteins. The most promising trait is the number of S.E. one day p.i.

Clonal variation in shoot respiration and tree growth of Eucalyptus hybrids

Respiration rate and efficiency in growing tissues are major determinants of plant growth. We measured apical shoot respiration and tree growth in 3-year-old clones of Eucalyptus camaldulensis Dehnhardt × Eucalyptus grandis W. Hill ex Maid. and Eucalyptus camaldulensis × Eucalyptus globulus Labill. Respiration was measured by isothermal calorimetry and the oxidation state of newly formed biomass was determined by elemental analysis. We found that the enthalpy change due to conversion of carbon substrate to biomass was too small for determining specific growth rate by an enthalpy balance model of respiration and growth. Negative phenotypic correlations were significant between respiration rate and basal area, height, volume, and volume growth. Genetic correlations between respiration rate and tree size or growth were mostly significant and estimates ranged from –0.55 to –1.02. Repeatability of the clone means was around 0.80 for respiration rate, 0.71–0.91 for summer growth, and in excess of 0.80 for tree size traits. The intraclass correlation for clones (within families) was 0.33 for rate of CO2 evolution and 0.45 for rate of metabolic heat evolution. Our results suggest considerable potential for altering respiration rate in breeding populations by selection, although the mechanisms linking respiration with growth require further investigation.

Population dynamics in a long‐lived seabird: I. Impact of breeding activity on survival and breeding probability in unbanded king penguins

Understanding the trade-off between current reproductive effort, future survival and future breeding attempts is crucial for demographic analyses and life history studies. We investigated this trade-off in a population of king penguins (Aptenodytes patagonicus) marked individually with transponders using multistate capture-recapture models. This colonial seabird species has a low annual proportion of non-breeders (13%), despite a breeding cycle which lasts over 1 year. To draw inferences about the consequences of non-breeding, we tested for an effect of reproductive activity on survival and on the probability of subsequent breeding. We found that birds non-breeding in year t show the same survival rate as breeders (two-states analysis: breeding and non-breeding). However, breeders had a lower probability of breeding again the following year. This negative phenotypic correlation suggests the existence of reproductive costs affecting future breeding probability, but it might also be strengthened by late arrival for courtship in year t. A three-state analysis including breeding success revealed that failed breeders in year t have a lower probability to reproduce successfully in year t + 1 than non-breeders in year t, providing some evidence for the existence of reproductive costs. Moreover, successful breeders showed higher survival probability. This positive phenotypic correlation between current reproduction and subsequent survival supports the hypothesis of an heterogeneity in individual quality. Males breeding in year t had a lower probability to breed again in year t + 1 than females, suggesting higher reproductive costs for this sex. Such additional costs might be due to higher male parental investment in the final phase of chick-rearing, which also delays the arrival of males in year t + 1, and decreases their breeding probability. Our study is the first to explore the breeding biology and the demography of penguins without the disturbance of flipper-bands.

Heritable variation in the foliar secondary metabolite sideroxylonal in Eucalyptus confers cross-resistance to herbivores

Plants encounter a broad range of natural enemies and defend themselves in diverse ways. The cost of defense can be reduced if a plant secondary metabolite confers resistance to multiple herbivores. However, there are few examples of positively correlated defenses in plants against herbivores of different types. We present evidence that a genetically variable chemical trait that acts as a strong antifeedant to mammalian herbivores of Eucalyptus also deters insect herbivores, suggesting a possible mechanism for cross-resistance. We provide field confirmation that sideroxylonal, an important antifeedant for mammalian herbivores, also determines patterns of damage by Christmas beetles, a specialist insect herbivore of Eucalyptus. In a genetic progeny trial of Eucalyptus tricarpa, we found significant heritabilities of sideroxylonal concentration (0.60), overall insect damage (0.34), and growth traits (0.30-0.53). Population of origin also had a strong effect on each trait. Negative phenotypic correlations were observed between sideroxylonal and damage, and between damage and growth. No relationship was observed between sideroxylonal concentration and any growth trait. Our results suggest that potential for evolution by natural selection of sideroxylonal concentrations is not strongly constrained by growth costs and that both growth and defense traits can be successfully incorporated into breeding programs for plantation trees.

Detection of QTL for yield-related traits using recombinant inbred lines derived from exotic and elite US Western Shipping melon germplasm

The inheritance of yield-related traits in melon (Cucumis melo L.; 2n = 2x = 24) is poorly understood, and the mapping of quantitative trait loci (QTL) for such traits has not been reported. Therefore, a set of 81 recombinant inbred lines (RIL) was developed from a cross between the monoecious, highly branched line USDA 846-1 and a standard vining, andromonoecious cultivar, 'Top Mark'. The RIL, parental lines, and three control cultivars ('Esteem', 'Sol Dorado', and 'Hales Best Jumbo') were grown at Hancock, WI and El Centro, CA in 2002, and evaluated for primary branch number (PB), fruit number per plant (FN), fruit weight per plant (FW), average weight per fruit (AWF), and percentage of mature fruit per plot (PMF). A 190-point genetic map was constructed using 114 RAPD, 43 SSR, 32 AFLP markers, and one phenotypic trait. Fifteen linkage groups spanned 1,116 cM with a mean marker interval of 5.9 cM. A total of 37 QTL were detected in both locations (PB = 6, FN = 9, FW = 12, AWF = 5, and PMF = 5). QTL analyses revealed four location-independent factors for PB (pb1.1, pb1.2, pb2.3, and pb10.5), five for FN (fn1.1, fn1.2, fn1.3, fn2.4, and fn8.8), four for FW (fw5.8, fw6.10, fw8.11, and fw8.12), two for AWF (awf1.3 and awf8.5), and one for PMF (pmf10.4). The significant (P </= 0.05) positive phenotypic correlations observed among PB, FN, and FW, and negative phenotypic correlations between PB and AWF and between FN and AWF were consistent with the genomic locations and effects (negative vs. positive) of the QTL detected. Results indicate that genes resident in highly branched melon types have potential for increasing yield in US Western Shipping type germplasm via marker-assisted selection.

Genetic Parameters For The Somatic Cells Count In The Milk Of Buffaloes UsingOrdinary Test Day Models

The buffaloes dairy milk production (BDMP) has increased in the last 20 years, mainly for the manufacturing of mozzarella cheese, which is recognized by its high nutritional quality. However, this quality can be affected by several factors i. e. high somatic cells count (SCC) provokes changes in the milk’s constituents. As in bovine dairy milk, the SCC is used as diagnostic tool for milk quality; because it enables the diagnosis of sub-clinic mastitis and also allows the selection of individuals genetically resistant to that disease. Based on it, we collected information about SCC and BDMP along the lactation in Murrah breed buffaloes, during the period between 1997 and 2005. Curves were designed to estimate genetic parameters. These parameters were estimated by ordinary test-day models. There were observed variations in the estimated heritability for both characteristics .The lowest score for somatic cells count (SSCC) was seen at first month (0.01) and the highest at sixth months (0.29 The genetic correlation between these traits varied from -1 at the 1 and 9th months to 0.31 and 0.30 in the2 and 4th month of lactation. Phenotypic correlations were all negative (-0.07 in the second month and up to -0.35 in the eighth month of lactation). These results showed that environmental factors are more important than genetics in explain SCC, for this reason, selection for genetic resistance to mastitis in buffalos based in SCC should not be done. In the other hand, negative phenotypic correlations demonstrated that as the SCC increased, the milk production decreased.

Realized correlated responses to artificial selection on pre-adult life-history traits in a butterfly

We use artificial selection experiments targeted on egg size, development time or pupal mass within a single butterfly population followed by a common-garden experiment to explore the interactions among these life-history traits. Relationships were predicted to be negative between egg size and development time, but to be positive between development time and body size and between egg size and body size. Correlated responses to selection were in part inconsistent with these predictions. Although there was evidence for a positive genetic correlation between egg and body size, there was no support for genetic correlations between larval development time and either egg size or pupal mass. Phenotypic correlations among the three target traits of selection gave comparable results for the relationships between egg mass and development time (no association) as well as between egg mass and pupal mass (positive association), but not for the relation between development time and pupal mass (negative phenotypic correlation). In summary, correlated responses to selection as well as phenotypic correlations were rather unpredictable. The impact of variation in acquisition and allocation of energy as well as of the benign conditions used deserve further investigation.