Heritability and Phenotypic Correlations of Six Pecan Nut Characteristics

Heritability estimates for pecan [Carya illinoinensis (Wangenh.) K. Koch] nut weight, nut buoyancy, nut volume, nut density, kernel weight, and percentage kernel were determined from 8748 nut samples representing 152 families collected during 25 years in the U.S. Dept. of Agriculture (USDA) pecan breeding program at Brownwood, Texas. Measurements were corrected for year-to-year environmental variability using least-squares constants of individual year effects. Adjusted values were then regressed on midparent means. Generally, heritability (h2) estimates were low to moderate: nut weight 0.35, nut buoyancy 0.18, nut volume 0.35, nut density 0.03, kernel weight 0.38, and percentage kernel 0.32. The low values are probably due to the extreme alternate bearing tendency of this species, since crop load affects pecan nut characteristics so directly. Phenotypic correlations among these traits showed that larger or heavier nuts had significantly higher kernel weight, buoyancy, and percentage kernel. Nut density increased with higher nut and kernel weight, but decreased with nut volume.

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SOME BIOMETRICAL STUDIES ON NINE AGRONOMIC TRAITS IN GRAIN SORGHUM, SORGHUM BICOLOR (L.) MOENCH: I. Variance Components and Heritability Estimates

Canadian Journal of Genetics and Cytology ◽

10.1139/g70-043 ◽

1970 ◽

Vol 12 (2) ◽

pp. 288-296 ◽

Cited By ~ 1

Author(s):

Jai H. Chung ◽

George H. L. Liang

Keyword(s):

Variance Components ◽

Environmental Variability ◽

Agronomic Traits ◽

Grain Sorghum ◽

Kernel Weight ◽

Components Of Variance ◽

Method Of Calculation ◽

First Order ◽

Heritability Estimates ◽

Lower Magnitude

The investigation was designed to estimate genetic and environmental variability and heritability for a number of agronomic characters in grain sorghum. The study was made in the F3 and F4 generations of three crosses grown at two locations in each of two years. Heritability estimates were computed by three methods: by variance components and by the regression of the F4 generation on the F3, using both conventional and standard-unit methods.In general, the genotypic components of variance were larger than those of the genotype × environment interactions. With few exceptions, second-order interactions were larger than first-order interactions. Although the first-order interactions are of lower magnitude, they should not be interpreted as though the genotype × year and genotype × location interactions did not exist; they may be a reflection of the nature of the lines tested and environments sampled. Most heritability estimates obtained from the three methods were in close agreement. Heritability estimates for half-bloom date, peduncle diameter, and plant height for all crosses were high regardless of the method of calculation. Grain yield, head weight, kernel weight, and kernel number showed moderately high heritability values, while those for head number and threshing percentage appeared to be low.

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Influence of Aminoethoxyvinylglycine on Pecan Fruit Retention

HortScience ◽

10.21273/hortsci.44.7.1884 ◽

2009 ◽

Vol 44 (7) ◽

pp. 1884-1889

Author(s):

Bruce W. Wood ◽

Leonardo Lombardini ◽

Richard J. Heerema

Keyword(s):

Crop Yield ◽

Field Studies ◽

Carya Illinoinensis ◽

Management Tool ◽

Load Management ◽

Crop Load ◽

Ethylene Inhibitor ◽

The U.S ◽

June Drop ◽

Increase Crop Yield

Insufficient fruit retention limits profitability of certain pecan [Carya illinoinensis (Wangenh.) K. Koch] cultivars. The present study examined efficacy of aminoethoxyvinylglycine (formulated as ReTain®; Valent BioSciences, Libertyville, IL), a natural ethylene inhibitor, for increasing crop-load through increased fruit retention in pecan trees grown at three distinct locations within the U.S. pecan belt. Several years of field studies found that timely postpollination ReTain® sprays [132 mg·L−1 a.i. (11.7 oz./acre)] to canopies could increase fruit retention of ‘Desirable’ and increase crop yield by 16% to 38% in trees carrying a “moderate to heavy” crop. ReTain® did not detectably increase fruit retention on trees carrying a “light” crop-load. The ReTain®-associated increase in yield of “heavy” crop-load trees did not necessarily decrease subsequent year yield. ReTain® appears to offer commercial potential as a crop-load management tool for ‘Desirable’ through regulation of Stage II drop (i.e., June-drop), but may not be efficacious for all cultivars.

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Fruit Production Characteristics of ‘Pawnee’ Pecan

HortScience ◽

10.21273/hortsci.47.4.489 ◽

2012 ◽

Vol 47 (4) ◽

pp. 489-496

Author(s):

Michael W. Smith

Keyword(s):

Fruit Production ◽

Quality Characteristics ◽

Kernel Weight ◽

Carya Illinoinensis ◽

Alternate Bearing ◽

Shell Weight ◽

Current Season ◽

Optimum Yield ◽

Optimum Production ◽

Production Characteristics

Yield and selected nut quality characteristics were monitored on hedge pruned ‘Pawnee’ pecan [Carya illinoinensis (Wangenh.) K. Koch.] trees over a 5-year period to characterize optimum production defined as equal crops 2 successive years. Previous year yield was linearly or quadratically related to current-season yield in three of four instances. Optimum yield ranged from 18 kg/tree to 29 kg/tree among years. Weight/nut, weight/kernel, and percent kernel were negatively related to yield/tree. Weight/nut and weight/kernel were more closely related to yield/tree than percent kernel, indicating that as cropload increased, shell weight and kernel weight were disproportionately affected. Increasing croploads reduced kernel weight more than shell weight, thus reducing the correlation between percent kernel and yield. Twenty-seven percent of the trees in the study produced greater than average yields with a lower than average alternate bearing index.

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Realized Sampling Variances of Estimates of Genetic Parameters and the Difference Between Genetic and Phenotypic Correlations

Genetics ◽

10.1093/genetics/143.3.1409 ◽

1996 ◽

Vol 143 (3) ◽

pp. 1409-1416 ◽

Cited By ~ 1

Author(s):

Kenneth R Koots ◽

John P Gibson

Keyword(s):

Genetic Correlation ◽

Genetic Parameters ◽

Genetic Parameter ◽

Genetic Correlations ◽

Phenotypic Correlation ◽

Parameter Estimates ◽

Sampling Variance ◽

Phenotypic Correlations ◽

Genetic And Phenotypic Correlations ◽

Heritability Estimates

Abstract A data set of 1572 heritability estimates and 1015 pairs of genetic and phenotypic correlation estimates, constructed from a survey of published beef cattle genetic parameter estimates, provided a rare opportunity to study realized sampling variances of genetic parameter estimates. The distribution of both heritability estimates and genetic correlation estimates, when plotted against estimated accuracy, was consistent with random error variance being some three times the sampling variance predicted from standard formulae. This result was consistent with the observation that the variance of estimates of heritabilities and genetic correlations between populations were about four times the predicted sampling variance, suggesting few real differences in genetic parameters between populations. Except where there was a strong biological or statistical expectation of a difference, there was little evidence for differences between genetic and phenotypic correlations for most trait combinations or for differences in genetic correlations between populations. These results suggest that, even for controlled populations, estimating genetic parameters specific to a given population is less useful than commonly believed. A serendipitous discovery was that, in the standard formula for theoretical standard error of a genetic correlation estimate, the heritabilities refer to the estimated values and not, as seems generally assumed, the true population values.

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Environmental Variability of Thousand Kernel Weight in Maize Hybrids of Different Maturity Groups

Poljoprivreda ◽

10.18047/poljo.27.2.6 ◽

2021 ◽

Vol 27 (2) ◽

pp. 50-55

Author(s):

Domagoj Stepinac ◽

Hrvoje Šarčević ◽

Ivica Buhiniček ◽

Mirko Jukić ◽

Bojan Marković ◽

...

Keyword(s):

Environmental Variability ◽

Kernel Weight ◽

Yield Component ◽

Maize Breeding ◽

Thousand Kernel Weight ◽

Maize Hybrids ◽

Component Trait ◽

Year Effect ◽

High Heritability ◽

Maturity Groups

Thousand kernel weight (TKW) is an important yield component trait affected by the environmental conditions. This study’s objectives were to determine an environmental variability for the TKW in 32 maize hybrids, sorted in four FAO maturity groups (FAO300, 400, 500 and 600), and to compare 12 environments in Croatia (six locations in two years) according to the joint linear regression and stability analyses across the maturity groups. In general, the effects of the environment, genotype, and their interaction (GEI) were significant. A three-factor ANOVA revealed the greatest and highly significant year effect, while the location effect was non-significant across all four FAO groups. A stability analysis did not detect any preferences with regard to the locations and trends across the FAO groups. It indicates that all locations in the Pannonian region included in this study were suitable for an evaluation of the TKW in maize genotypes belonging to all maturity groups. The TKW seems to be an appropriate yield-component trait for maize breeding due to a high heritability and linear GEI nature.

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Genetic parameter estimates (full sib and half sib analysis) of fertility and hatchability in two strains of Rhode Island chickens

Nigerian Journal of Animal Production ◽

10.51791/njap.v38i1.706 ◽

2021 ◽

Vol 38 (1) ◽

pp. 14-22

Author(s):

M. Orunmuyi ◽

I. A. Adeyinka ◽

O.O Oni

Keyword(s):

Rhode Island ◽

Additive Genetic Variance ◽

Genetic Parameter ◽

Genetic Correlations ◽

Reproductive Traits ◽

Parameter Estimates ◽

Phenotypic Correlations ◽

Poultry Breeding ◽

Genetic And Phenotypic Correlations ◽

Heritability Estimates

A study was conducted to estimate the genetic parameters of fertility and hatchability in two strains of Rhode Island Red (RIR) Chickens denoted as Strain A and Strain B respectively using the full-sib (sire +dam variance) and maternal half-sib (dam variance) components. The birds were obtained from the selected populations of RIR Chickens kept at the poultry breeding programme of National Animal Production Research Institute, Shika, Zaria, Nigeria. Settable eggs were collected from mating 28 cocks to 252 hens in a ratio of 1cock:9 hens from each strain. Eggs were pedigreed according to sire and dam. Results showed that values obtained for number of egg set (EGGSET), number of fertile eggs (NFERT), number of hatched chicks (NHATCH), percentage of chicks hatched from total eggs set (PHATCH) and percentage of chicks hatched from fertile eggs (PHATCHBL) were all higher in strain A than strain B. Heritability estimates obtained from the full-sib and maternal half-sib analysis ranged from medium to high for the two strains (0.24-0.96). The maternal half sib estimates were higher (0.40-0.96) than the estimates obtained from full sibs (0.24- 0.48). Genetic and phenotypic correlations obtained for both strains were positive and similar regardless of method of estimation. Genetic correlations between EGGSET and PFERT were low in strain A using both full-sib and maternal half-sib analyses (0.09-0.14). Phenotypic correlations between EGGSET and PFERT, PHATCH and PHATCHBL were also low in both strains and regardless of method of analyses. Moderate to high heritability estimates suggest that genetic improvement can be obtained by selection of these reproductive traits. The full-sib analysis for estimating heritability will be preferred since it is assumed that only additive genetic variance contributes to the covariance between family members.

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Estimates of genetic and phenotypic parameters of some weight and fleece traits in a coarse-wool breed of sheep

The Journal of Agricultural Science ◽

10.1017/s0021859600030033 ◽

1982 ◽

Vol 99 (2) ◽

pp. 277-285 ◽

Cited By ~ 1

Author(s):

R. A. Guirgis ◽

E. A. Afifi ◽

E. S. E. Galal

Keyword(s):

Body Weight ◽

Genetic Correlations ◽

Phenotypic Correlations ◽

Body Weights ◽

Heritability Estimates ◽

Fleece Weight ◽

Staple Length

SUMMARYA study using 1150 lambs to estimate genetic and phenotypic parameters of some weight and fleece traits was carried out on coarse-wool Barki sheep. The weight traits were birth, weaning, yearling weights and daily gains whereas fleece traits included kemp score, staple length and greasy-fleece weight.Heritability estimates of weight traits were within the range 0·25–0·30. Those of fleece traits were 0·16, 0·21 and 0·43. The repeatability estimates of fleece traits were 0·18, 0·38 and 0·53 for staple length, greasy-fleece weight and kemp score respectively.Phenotypic correlations between body weight and fleece traits were mostly positive. Genetic correlations between greasy-fleece weight and body weights were mostly positive and of medium values. Those between kemp score and body weights were mostly negative, ranging from medium-high to high.

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The Effect of Pay and Retention Bonuses on Quit Rates in the U.S. Army

ILR Review ◽

10.1177/001979398804100307 ◽

1988 ◽

Vol 41 (3) ◽

pp. 430-438 ◽

Cited By ~ 14

Author(s):

Hyder Lakhani

Keyword(s):

Labor Market ◽

Least Squares ◽

Quit Rate ◽

General Skills ◽

Three Stage Least Squares ◽

The U.S ◽

Combat Soldiers

This paper investigates the effects of pay and reenlistment bonuses on quit rates in the U.S. Army. A three stage least squares analysis of 1981 data shows that quit rates were negatively related to pay level and, even more so, to the size of the bonus offered. The effects on the quit rate were significantly greater, however, for soldiers in combat occupations than for those in noncombat occupations. The author speculates that the skills learned by combat soldiers are less marketable in the civilian labor market than the more general skills acquired by noncombat soldiers; he thus urges higher bonuses in noncombat occupations.

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The role of selection in the improvement of Welsh Mountain sheep

Australian Journal of Agricultural Research ◽

10.1071/ar9580819 ◽

1958 ◽

Vol 9 (6) ◽

pp. 819 ◽

Cited By ~ 3

Author(s):

JM Doney

Keyword(s):

Birth Weight ◽

Maternal Environment ◽

Weaning Weight ◽

Phenotypic Correlations ◽

Selection For ◽

Heritability Estimates ◽

Fleece Weight ◽

Staple Length

Means and variances of several economic characters in Welsh Mountain sheep are given. The repeatabilities of, and phenotypic correlations between, these characters are generally within the range of similar estimates given for other breeds. Heritabilities, calculated from parent-offspring correlations, were : birth weight 0.39, weaning weight 0.68, 18-month weight 0.59, greasy fleece weight 0.61, and staple length 0.73. These values are in general higher than similarly derived estimates from other breeds. A method of correcting heritability estimates to remove the error due to correlation between maternal environment, and the character as measured in the dam, is described. This reduces the estimate for weaning weight to 0.48, and that for 18-month weight to 0.16, but does not change that for fleece weight. The use of such estimates in predicting the effect of selection is discussed, and it is concluded that accurate selection for the chosen economic characters will result in improvement at the present genetic stage of the breed.

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RELATIONSHIPS OF REPRODUCTION TRAITS, BODY WEIGHT AND MILK YIELD IN DAIRY CATTLE

Canadian Journal of Animal Science ◽

10.4141/cjas86-007 ◽

1986 ◽

Vol 66 (1) ◽

pp. 53-65 ◽

Cited By ~ 11

Author(s):

T. R. BATRA ◽

A. J. LEE ◽

A. J. McALLISTER

Keyword(s):

Body Weight ◽

Dairy Cattle ◽

Milk Yield ◽

Fixed Effects ◽

Genetic Correlations ◽

Calving Interval ◽

Phenotypic Correlations ◽

Reproduction Traits ◽

Heritability Estimates ◽

National Cooperative

The relationships between reproduction traits, body weight and milk yield were investigated using data from 1611 heifers and 733 cows from two lines of the National Cooperative Dairy Cattle Breeding Project. The data were analyzed separately for heifers and cows within lines using a mixed linear model containing fixed effects for station, year of birth, season of birth and random effect of sires. Heritability estimates and genetic correlations were estimated by a paternal half-sib analysis. Heritability estimates for heifer and cow reproduction traits ranged between 0 and 26% while those of body weights at calving and 112 d postpartum and milk yield ranged from 24 to 43%. Heifers with difficult calving had a higher incidence of retained placenta than those with normal calving. Phenotypic correlations between heifer reproduction traits and milk yield during first lactation were small. High milk production in cows was associated with longer calving interval. Phenotypic correlations between heifer's and cow's reproduction traits were small. Difficult calving in heifers impairs reproductive performance after calving resulting in greater number of days from calving to first and last breeding and leading to a longer calving interval. Key words: Reproduction traits, heifers, cows, milk yield, dairy cattle

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