- Email: [email protected]
Heritability of Body Weight in the Domestic Fowl
50
B. L. GOODMAN AND G. F. GODFREY
Hazel, L. N., 1943. The genetic basis for constructing sélection indexes. Genetics, 28:476-490. Leraer, I. M., V. S. Asmundson and D. M. Cruden, 1947. The improvement of New Hampshire fryers. Poultry Sci. 26: 515-524. Lerner, I. M., 1950. Population Genetics and Animal Improvement. Cambridge University Press.
Jull, M. A., 1952. Poultry Breeding. 3rd Ed. John Wiley & Sons, Inc., New York. Lush, J. L., 1941. Intra-sire corrélations or régressions of offspring on dam as a method of estimating heritability of characteristics. Proc. Amer. Soc. Anim. Prod. for 1940: 293-301.
Heritability of Body Weight in the Domestic Fowl Oklahoma Agricultural Experiment Station, Stillwaler (Received for publication June 1, 1955)
B
ODY weight of broilers has been an important trait for a considérable number of years. More recently, breeders of egg production strains hâve become interested in adult body weight; the trend seems to be toward a small-bodied layer in order to reduce the amount of feed required for body maintenance. Heritability estimâtes aid the breeder in choosing the most efficient sélection method and breeding System. With body weight being an important trait to ail breeders, it seems désirable to consolidate ail heritability estimâtes of this trait, as well as to report those that hâve been calculated at the Oklahoma Agricultural Experiment Station during the past four years. REVIEW OF THE LITERATURE
Heritability estimâtes of body weight, as found in the literature, are summarized by âge and method of estimation in Table 1. A simple, arithmetic average of thèse estimâtes by âges show that the heritability of body weight at broiler âge, and at housing or at mature weight, averages about 0.3 and 0.4 respectively. It should be noted that the eight estimâtes, ranging 1 Présent address: Honeggers' Farms Co., Inc., Forrest, Illinois.
from 0.42 to 0.61, calculated by Comstock, Bostian and Dearstyne (1947), as quoted by Shoffner and Sloan (1948), are not included in Table 1 nor in the simple averages, because the âge of birds and methods of calculation were not known. Two points should be kept in mind about thèse estimâtes: (1) Différent methods of estimation include varying amounts of non-additive genetic variance; and (2) thèse estimâtes may differ from population to population, and even from génération to génération within the same population. A detailed discussion of thèse points may be found in publications by Lush (1948) or Lerner (1950). MATERIALS AND METHODS
Heritability estimâtes for 9-week body weight and mature body weight (10 to 11 months of âge) hâve been calculated for four générations for the New Hampshire and Silver Oklabar populations maintained on the Oklahoma Agricultural Experiment Station. The New Hampshire population originated from many of the outstanding commerical strains, but it has been maintained as a closed flock since 1949. The Silver Oklabars originated from the systematic crossing of Rhode Island Reds, White Plymouth Rocks, Dark Cornish and Silver-laced Wyandottes
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 4, 2015
B. L. GOODMAN AND GEORGE F. GODFREY1
51
H E R I T A B I L I T Y OF B O D Y W E I G H T
TABLE 1.—Heritability estimâtes of body weight Method of Estimation Age
4D
45
Référence
2(D+S) 2bCd
Other
30
19,30
Q+D+S Q+D+S Q+D+S 2 Weeks 6 Weeks
31-44 81 28-38
0-6 59 13-14
19,30 11-22 35 13-26 • 29
10 Weeks
32
40
42 15
20-63 31 32
12 Weeks 40 42 45 32 85
22 Weeks Sexual Maturity 10 Months Housing December Mature
51-79 60 66
51 56
17
31 32
48
71
72 75
31 43 47 65
18 32
80,49 52
from the results, it seems unlikely t h a t this mating scheme deviated much from the restricted random mating scheme of subséquent générations. Table 2 shows the number of matings, progeny and hatches involved in each génération. Heritability estimâtes of 9-week body weight a n d m a t u r e body weight were calculated for four générations of New Hampshires and Silver Oklabars from variance components and from the intra-
(Godfrey and Thompson, 1953). T h e y hâve been maintained as a closed fiock for a t least ten years. On the basis of their origin, they might be expected to be more heterogeneous t h a n the New Hampshire population. Ail générations reported in this study, except the 1951 génération, were mated a t random, with the restriction t h a t no full or half-sib matings were practiced. Assortative and non-assortative phenotypic matings were practiced to some extent in the 1951 génération; b u t ,
TABLE 2.—Number of sires,fiams, progeny and hatches by breed and génération New Hampshires
Silver Oklabars Génération
1951 1952 1953 1954 M F
No.
No. sires
No. dams
progeny
No. hatches
No. sires
No. dams
No. progeny
No. hatches
8 8 9
87 67 86
1,931 1,883 1,986
7 6 5
10 12 12
129 131 140
3,066 3,608 2,481
7 6 5
10 10
98 96
924 891
4 4
15 15
156 158
1,556 1,507
4 4
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 4, 2015
34 37-27 33 46 50 21-54 38
8 Weeks
El-Ibiary and Shafîner, 1951 Williams, 1952 El-Ibiary and Shaffner, 1951 Godfrey and Williams, 1952 Dillard et al., 1953 El-Ibiary and Shaffner, 1951 Hurry and Nordskog, 1953 Wyatt, 1954 Fagan, 1949 El-Ibiary and Shaffner, 1951 Peeler et al., 1955 Lankford and McClung, 1952 Godfrey and Williams, 1952 Garber and Godbey, 1952 Glazener et ai., 1951 Lerner et ai., 1947 Williams, 1952 Hazel and Lamoreux, 1947 Peeler et al., 1955 Shoffner and Sloan, 1948 Wyatt, 1954 Krueger et ai., 1952 Lerner and Cruden, 1951 Wyatt, 1954
52
B. L. GOODMAN AND G. F. GODFREY TABLE 3.—Heritability estimâtes of Ç-week body weight of New Hampshires and Silver Oklàbars Silver Oklàbars
New Hampshires Génération
45
AD
45
2(D+S)
AD
2(S+D)
2bod Q+D+S 1951 1952 1953 1954 M F
Q+D+S
2bod Q+D+S
Q+D+S
Q+D+S
Q+D+S
.28 .28 .08
.65 .52 .74
.48 .40 .41
.22+.04 .49+.03 .34+.03
.30 .41 .45
.51 .80 .51
.41 .60 .48
.34+.03 .50+.06 . 3 7 + . 05
.16 .23
.55 .65
.35 .44
.28+.04 .36+ .04
.63 .56
.49 .42
.56 .49
.20+.08 .20±.07
RESULTS AND DISCUSSION Heritability estimâtes of 9-week body weight of the New Hampshires and Silver Oklàbars are shown in Table 3. Estimâtes calculated by the intrasire régression of offspring on dam averaged a little more than 0.3. Those calculated from variance components averaged slightly more than 0.4. The estimâtes for Silver Oklàbars tend to be slightly higher than those for New Hampshires. This slight breed différence is largely due to sampling variation, but the possibility of a breed différence should not be overlooked. There seems to be little, if any, consistent différence between sexes within breeds as shown in the 1954 analysis where the data for maies and females were analyzed separately. Heritability estimâtes of mature pullet body weight are shown in Table 4. Intrasire régression estimâtes averaged about 0.4, while those calculated from variance components averaged slightly higher. The
estimâtes for Silver Oklàbars are slightly higher than those calculated for the New Hampshires. Although this différence is significant, explanation of it other than in terms of sampling variation and différences in gène frequency seem unwarranted at présent. Thèse two populations hâve been selected for body weight at nine weeks of âge for a number of years, but no decrease in genetic variance is évident as measured by the heritability estimâtes within the four générations reported. Whether or not the estimâtes herein reported represent "effective" heritability must await results of sélection experiments in progress. Based on thèse estimâtes, as well as those previously reported in the literature mass or individual sélection appears to be the most effective method of sélection for the improvement either of broiler body weight or mature body weight. SUMMARY Heritability estimâtes were calculated from variance components and intrasire
TABLE 4.-—Heritability estimâtes of mature pullet body weight of New Hampshires and Silver Oklàbars New Hampshires Génération
45
AD
Silver Oklàbars
2(Z>+5)
45
AD
2(£>+5)
2boc
Q+D+SQ+D+SQ+D+S 1951 1952 1953 1954
.35 .51 .47 .52
.47 .21 .59 .27
Q+D+S .41 .36 .53 .39
.34+ .39 + .33 + .40 +
04 04 06 04
.43 .34 .57 .45
Q+D+S .90 .81 .41 .59
Q+D+S .67 .58 .49 .52
2b„ ! .46 + .43 + .47 + .40 +
04 08 04 04
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 4, 2015
sire régression of offspring on dam. Correction was made for hatch effects.
NEWS AND NOTES
régression of offspring on dam for 9-week body weight and mature body weight for four générations of New Hampshires and Silver Oklabars. Estimâtes for heritability of 9-week body weight averaged about 0.43 ; those for mature pullet body weight averaged about 0.47. Individual sélection is thus the most efficient sélection method to improve either broiler body weight or mature body weight in thèse populations.
Dillard, E. U., G. E. Dickerson and W. F. Lamoreaux, 19S3. Heritabilities of egg and méat production qualities and their genetic and environmental relationships in New Hampshire pullets. PoultrySci.32:897. El-Ibiary, H. M., and C. S. Shaffner, 1951. The effect of induced hypothyroidism on the genetics of growth in the chicken. Poultry Sci. 30: 435-444. Fagan, H. B., 1949. Hereditary and environmental factors influencing chick weight at eight weeks. M.S. Thesis, Iowa State Collège. Garber, M. J., and C. B. Godbey, 1952. The influence of sire, dam, and hatching date on spécifie rate of growth of Single Comb White Leghorn pullets from hatching to 12 weeks of âge. Poultry Sci. 31:945-955. Glazener, E. W., W. L. Blow, C. H. Bostian and R. S. Dearstyne, 1951. Effect of inbreeding on broiler weights and feathering in the fowl. Poultry Sci. 30: 108-112. Godfrey, G. F., and C. Williams, 1952. Heritability of growth in the domestic fowl. Genetics, 37: 585. Godfrey, G. F., and R. B. Thompson, 1953. Silver Oklabars, their origin and présent development. Oklahoma Agr. Expt. Sta. Bul. B-394. Hazel, L. N., and W. F. Lamoreaux, 1947. Heritabil-
ity, maternai effects and nicking in relation to sexual maturity and body weight in White Leghorns. Poultry Sci. 26:508-514. Hurry, H. F., and A. W. Nordskog, 1953. A genetic analysis of chick feathering and its influence on growth rate. Poultry Sci. 32:18-25. Krueger, W. F., G. E. Dickerson, Q. B. Kinder and H. L. Kempster, 1952. The genetic and environmental relationship of total egg production to its components and to body weight in the domestic fowl. Poultry Sci. 31:922-923. Lankford, L., and M. R. McClung, 1952. Heritability of 10 week weight in a broiler strain of chickens. Poultry Sci. 31:923. Lerner, I. M., V. S. Asmundson and T>. M. Cruden, 1947. The improvement of New Hampshire fryers. Poultry Sci. 26: 515-524. Lerner, I. M., 1950. Population Genetics and Animal Improvement. Cambridge University Press, Cambridge. Lerner, I. M., and D. M. Cruden, 1951. The heritability of egg weight: The advantages of mass sélection and early measurements. Poultry Sci. 30: 34-41. Lush, J. L., 1948. The Genetics of Populations. Ames, Iowa. Peeler, R. J., E. W. Glazener and W. L. Blow, 1955. The heritability of broiler weight and weight and âge at sexual maturity and the genetic and environmental corrélations between thèse traits. Poultry Sci. 34:420-426. Shoffner, R. N., and H. J. Sloan, 1948. Heritability studies in the domestic fowl. Proc. 8th World's Poultry Congress. 1:269-281. Williams, C. N., 1952. The relative influence of heredity and environment on the early growth rate of the chicken. M.S. Thesis, Oklahoma A. & M. Collège. Wyatt, A. J., 1954. Genetic variation and covariation in egg production and other économie traits in chickens. Poultry Sci. 33:1266-1274.
NEWS AND NOTES {Continuée from page 46) and Egg National Board, 185 North Wabash Ave., Chicago 1, Illinois. Nominations are received once in each threeyear period, and not more than Ave persons may be admitted during any three-year period. The Hall of Famé is located in Jull Hall, University of Maryland. Portraits of S. S. Barker, W. R. Graham, L. B. Kilbourne, J. E. Rice and C. W. Wampler hang in the Hall.
NEWMAN MEMORIAL AWARD COMMITTEE With the retirement of Dr. Morley A. Jull from the University of Maryland and his acceptance of a two-year assignment in Egypt, Dr. V. S. Asmundson, Poultry Department, University of California, Davis, is now Chairman of the United States Nominating Committee to propose a candidate each year for the Tom Newman Mémorial Award which
(Continued on page 84)
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 4, 2015
REFERENCES
53
B. L. GOODMAN AND G. F. GODFREY
Hazel, L. N., 1943. The genetic basis for constructing sélection indexes. Genetics, 28:476-490. Leraer, I. M., V. S. Asmundson and D. M. Cruden, 1947. The improvement of New Hampshire fryers. Poultry Sci. 26: 515-524. Lerner, I. M., 1950. Population Genetics and Animal Improvement. Cambridge University Press.
Jull, M. A., 1952. Poultry Breeding. 3rd Ed. John Wiley & Sons, Inc., New York. Lush, J. L., 1941. Intra-sire corrélations or régressions of offspring on dam as a method of estimating heritability of characteristics. Proc. Amer. Soc. Anim. Prod. for 1940: 293-301.
Heritability of Body Weight in the Domestic Fowl Oklahoma Agricultural Experiment Station, Stillwaler (Received for publication June 1, 1955)
B
ODY weight of broilers has been an important trait for a considérable number of years. More recently, breeders of egg production strains hâve become interested in adult body weight; the trend seems to be toward a small-bodied layer in order to reduce the amount of feed required for body maintenance. Heritability estimâtes aid the breeder in choosing the most efficient sélection method and breeding System. With body weight being an important trait to ail breeders, it seems désirable to consolidate ail heritability estimâtes of this trait, as well as to report those that hâve been calculated at the Oklahoma Agricultural Experiment Station during the past four years. REVIEW OF THE LITERATURE
Heritability estimâtes of body weight, as found in the literature, are summarized by âge and method of estimation in Table 1. A simple, arithmetic average of thèse estimâtes by âges show that the heritability of body weight at broiler âge, and at housing or at mature weight, averages about 0.3 and 0.4 respectively. It should be noted that the eight estimâtes, ranging 1 Présent address: Honeggers' Farms Co., Inc., Forrest, Illinois.
from 0.42 to 0.61, calculated by Comstock, Bostian and Dearstyne (1947), as quoted by Shoffner and Sloan (1948), are not included in Table 1 nor in the simple averages, because the âge of birds and methods of calculation were not known. Two points should be kept in mind about thèse estimâtes: (1) Différent methods of estimation include varying amounts of non-additive genetic variance; and (2) thèse estimâtes may differ from population to population, and even from génération to génération within the same population. A detailed discussion of thèse points may be found in publications by Lush (1948) or Lerner (1950). MATERIALS AND METHODS
Heritability estimâtes for 9-week body weight and mature body weight (10 to 11 months of âge) hâve been calculated for four générations for the New Hampshire and Silver Oklabar populations maintained on the Oklahoma Agricultural Experiment Station. The New Hampshire population originated from many of the outstanding commerical strains, but it has been maintained as a closed flock since 1949. The Silver Oklabars originated from the systematic crossing of Rhode Island Reds, White Plymouth Rocks, Dark Cornish and Silver-laced Wyandottes
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 4, 2015
B. L. GOODMAN AND GEORGE F. GODFREY1
51
H E R I T A B I L I T Y OF B O D Y W E I G H T
TABLE 1.—Heritability estimâtes of body weight Method of Estimation Age
4D
45
Référence
2(D+S) 2bCd
Other
30
19,30
Q+D+S Q+D+S Q+D+S 2 Weeks 6 Weeks
31-44 81 28-38
0-6 59 13-14
19,30 11-22 35 13-26 • 29
10 Weeks
32
40
42 15
20-63 31 32
12 Weeks 40 42 45 32 85
22 Weeks Sexual Maturity 10 Months Housing December Mature
51-79 60 66
51 56
17
31 32
48
71
72 75
31 43 47 65
18 32
80,49 52
from the results, it seems unlikely t h a t this mating scheme deviated much from the restricted random mating scheme of subséquent générations. Table 2 shows the number of matings, progeny and hatches involved in each génération. Heritability estimâtes of 9-week body weight a n d m a t u r e body weight were calculated for four générations of New Hampshires and Silver Oklabars from variance components and from the intra-
(Godfrey and Thompson, 1953). T h e y hâve been maintained as a closed fiock for a t least ten years. On the basis of their origin, they might be expected to be more heterogeneous t h a n the New Hampshire population. Ail générations reported in this study, except the 1951 génération, were mated a t random, with the restriction t h a t no full or half-sib matings were practiced. Assortative and non-assortative phenotypic matings were practiced to some extent in the 1951 génération; b u t ,
TABLE 2.—Number of sires,fiams, progeny and hatches by breed and génération New Hampshires
Silver Oklabars Génération
1951 1952 1953 1954 M F
No.
No. sires
No. dams
progeny
No. hatches
No. sires
No. dams
No. progeny
No. hatches
8 8 9
87 67 86
1,931 1,883 1,986
7 6 5
10 12 12
129 131 140
3,066 3,608 2,481
7 6 5
10 10
98 96
924 891
4 4
15 15
156 158
1,556 1,507
4 4
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 4, 2015
34 37-27 33 46 50 21-54 38
8 Weeks
El-Ibiary and Shafîner, 1951 Williams, 1952 El-Ibiary and Shaffner, 1951 Godfrey and Williams, 1952 Dillard et al., 1953 El-Ibiary and Shaffner, 1951 Hurry and Nordskog, 1953 Wyatt, 1954 Fagan, 1949 El-Ibiary and Shaffner, 1951 Peeler et al., 1955 Lankford and McClung, 1952 Godfrey and Williams, 1952 Garber and Godbey, 1952 Glazener et ai., 1951 Lerner et ai., 1947 Williams, 1952 Hazel and Lamoreux, 1947 Peeler et al., 1955 Shoffner and Sloan, 1948 Wyatt, 1954 Krueger et ai., 1952 Lerner and Cruden, 1951 Wyatt, 1954
52
B. L. GOODMAN AND G. F. GODFREY TABLE 3.—Heritability estimâtes of Ç-week body weight of New Hampshires and Silver Oklàbars Silver Oklàbars
New Hampshires Génération
45
AD
45
2(D+S)
AD
2(S+D)
2bod Q+D+S 1951 1952 1953 1954 M F
Q+D+S
2bod Q+D+S
Q+D+S
Q+D+S
Q+D+S
.28 .28 .08
.65 .52 .74
.48 .40 .41
.22+.04 .49+.03 .34+.03
.30 .41 .45
.51 .80 .51
.41 .60 .48
.34+.03 .50+.06 . 3 7 + . 05
.16 .23
.55 .65
.35 .44
.28+.04 .36+ .04
.63 .56
.49 .42
.56 .49
.20+.08 .20±.07
RESULTS AND DISCUSSION Heritability estimâtes of 9-week body weight of the New Hampshires and Silver Oklàbars are shown in Table 3. Estimâtes calculated by the intrasire régression of offspring on dam averaged a little more than 0.3. Those calculated from variance components averaged slightly more than 0.4. The estimâtes for Silver Oklàbars tend to be slightly higher than those for New Hampshires. This slight breed différence is largely due to sampling variation, but the possibility of a breed différence should not be overlooked. There seems to be little, if any, consistent différence between sexes within breeds as shown in the 1954 analysis where the data for maies and females were analyzed separately. Heritability estimâtes of mature pullet body weight are shown in Table 4. Intrasire régression estimâtes averaged about 0.4, while those calculated from variance components averaged slightly higher. The
estimâtes for Silver Oklàbars are slightly higher than those calculated for the New Hampshires. Although this différence is significant, explanation of it other than in terms of sampling variation and différences in gène frequency seem unwarranted at présent. Thèse two populations hâve been selected for body weight at nine weeks of âge for a number of years, but no decrease in genetic variance is évident as measured by the heritability estimâtes within the four générations reported. Whether or not the estimâtes herein reported represent "effective" heritability must await results of sélection experiments in progress. Based on thèse estimâtes, as well as those previously reported in the literature mass or individual sélection appears to be the most effective method of sélection for the improvement either of broiler body weight or mature body weight. SUMMARY Heritability estimâtes were calculated from variance components and intrasire
TABLE 4.-—Heritability estimâtes of mature pullet body weight of New Hampshires and Silver Oklàbars New Hampshires Génération
45
AD
Silver Oklàbars
2(Z>+5)
45
AD
2(£>+5)
2boc
Q+D+SQ+D+SQ+D+S 1951 1952 1953 1954
.35 .51 .47 .52
.47 .21 .59 .27
Q+D+S .41 .36 .53 .39
.34+ .39 + .33 + .40 +
04 04 06 04
.43 .34 .57 .45
Q+D+S .90 .81 .41 .59
Q+D+S .67 .58 .49 .52
2b„ ! .46 + .43 + .47 + .40 +
04 08 04 04
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 4, 2015
sire régression of offspring on dam. Correction was made for hatch effects.
NEWS AND NOTES
régression of offspring on dam for 9-week body weight and mature body weight for four générations of New Hampshires and Silver Oklabars. Estimâtes for heritability of 9-week body weight averaged about 0.43 ; those for mature pullet body weight averaged about 0.47. Individual sélection is thus the most efficient sélection method to improve either broiler body weight or mature body weight in thèse populations.
Dillard, E. U., G. E. Dickerson and W. F. Lamoreaux, 19S3. Heritabilities of egg and méat production qualities and their genetic and environmental relationships in New Hampshire pullets. PoultrySci.32:897. El-Ibiary, H. M., and C. S. Shaffner, 1951. The effect of induced hypothyroidism on the genetics of growth in the chicken. Poultry Sci. 30: 435-444. Fagan, H. B., 1949. Hereditary and environmental factors influencing chick weight at eight weeks. M.S. Thesis, Iowa State Collège. Garber, M. J., and C. B. Godbey, 1952. The influence of sire, dam, and hatching date on spécifie rate of growth of Single Comb White Leghorn pullets from hatching to 12 weeks of âge. Poultry Sci. 31:945-955. Glazener, E. W., W. L. Blow, C. H. Bostian and R. S. Dearstyne, 1951. Effect of inbreeding on broiler weights and feathering in the fowl. Poultry Sci. 30: 108-112. Godfrey, G. F., and C. Williams, 1952. Heritability of growth in the domestic fowl. Genetics, 37: 585. Godfrey, G. F., and R. B. Thompson, 1953. Silver Oklabars, their origin and présent development. Oklahoma Agr. Expt. Sta. Bul. B-394. Hazel, L. N., and W. F. Lamoreaux, 1947. Heritabil-
ity, maternai effects and nicking in relation to sexual maturity and body weight in White Leghorns. Poultry Sci. 26:508-514. Hurry, H. F., and A. W. Nordskog, 1953. A genetic analysis of chick feathering and its influence on growth rate. Poultry Sci. 32:18-25. Krueger, W. F., G. E. Dickerson, Q. B. Kinder and H. L. Kempster, 1952. The genetic and environmental relationship of total egg production to its components and to body weight in the domestic fowl. Poultry Sci. 31:922-923. Lankford, L., and M. R. McClung, 1952. Heritability of 10 week weight in a broiler strain of chickens. Poultry Sci. 31:923. Lerner, I. M., V. S. Asmundson and T>. M. Cruden, 1947. The improvement of New Hampshire fryers. Poultry Sci. 26: 515-524. Lerner, I. M., 1950. Population Genetics and Animal Improvement. Cambridge University Press, Cambridge. Lerner, I. M., and D. M. Cruden, 1951. The heritability of egg weight: The advantages of mass sélection and early measurements. Poultry Sci. 30: 34-41. Lush, J. L., 1948. The Genetics of Populations. Ames, Iowa. Peeler, R. J., E. W. Glazener and W. L. Blow, 1955. The heritability of broiler weight and weight and âge at sexual maturity and the genetic and environmental corrélations between thèse traits. Poultry Sci. 34:420-426. Shoffner, R. N., and H. J. Sloan, 1948. Heritability studies in the domestic fowl. Proc. 8th World's Poultry Congress. 1:269-281. Williams, C. N., 1952. The relative influence of heredity and environment on the early growth rate of the chicken. M.S. Thesis, Oklahoma A. & M. Collège. Wyatt, A. J., 1954. Genetic variation and covariation in egg production and other économie traits in chickens. Poultry Sci. 33:1266-1274.
NEWS AND NOTES {Continuée from page 46) and Egg National Board, 185 North Wabash Ave., Chicago 1, Illinois. Nominations are received once in each threeyear period, and not more than Ave persons may be admitted during any three-year period. The Hall of Famé is located in Jull Hall, University of Maryland. Portraits of S. S. Barker, W. R. Graham, L. B. Kilbourne, J. E. Rice and C. W. Wampler hang in the Hall.
NEWMAN MEMORIAL AWARD COMMITTEE With the retirement of Dr. Morley A. Jull from the University of Maryland and his acceptance of a two-year assignment in Egypt, Dr. V. S. Asmundson, Poultry Department, University of California, Davis, is now Chairman of the United States Nominating Committee to propose a candidate each year for the Tom Newman Mémorial Award which
(Continued on page 84)
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 4, 2015
REFERENCES
53