tailieunhanh - báo cáo khoa học: "Comparisons of selection indices achieving predetermined proportional gains"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Comparisons of selection indices achieving predetermined proportional gains | Génét. Sél. Evol. 1987 19 1 69-82 Comparisons of selection indices achieving predetermined proportional gains Y. ITOH and Y. YAMADA Department of Animal Science College of Agriculture Kyoto University Kyoto 606 Japan Summary There are 3 different selection indices to achieve predetermined proportional gains in some traits. One is a modification of the restricted selection index of Kempthorne Nordskog 1959 and the others are indices with proportional constraints proposed by Harville 1975 and Tallis 1985 . They are described in uniform notations and their equivalence is proved algebraically. Key words Restricted selection index proportional constraints improvement in desired direction. Resume Comparaison d indices de selection pour des gains respectant des proportions fixees à I avance Il existe 3 indices de selection differents qui permettent d obtenir des gains respectant des proportions fixees à 1 avance. L un résulte d une modification de rindice de selection restreint de Kempthorne Nordskog 1959 les 2 autres sont des indices avec contraintes proportionnelles proposes par Harville 1975 et Tallis 1985 . Ils sont décrits avec des notations homogènes et leur equivalence est démontrée algébriquement. Mots clés Index de selection restreint contraintes proportionnelles progrès dans une direction. I. Introduction Kempthorne Nordskog 1959 proposed a selection index which ensured zero selection gain in some character. Tallis 1962 extended their method and proposed an index which allowed progresses to pre set optimal levels in certain characters. However Mallard 1972 criticized that the method of Tallis was not optimal and indicated how optimality could be achieved. Harville 1975 proposed an index with proportional constraints which shifted the 70 Y. ITOH Y. YAMADA means of some characters in desired direction. This method was more efficient than the procedure of Tallis. Recently Tallis 1985 accepted the criticism and presented a more general solution to this original .