INDEX 673 
System, of labelling and recording data, 423 
of pedigree, 293 
of reaction, in species, 242, 286 
Svaléf, 425 
Systems of breeding, 580 
T 
Tanaka, linkage relations, 209, 210 
multiple allelomorphs in silkworms, 158 
Telegony, 564, 570 © 
Teosinte, crossed with maize, 296 
Terminology, Mendelian, 71 
Tetrahybrid ratio, 94 
Tetraploidy, 263 
causing gigantism, 264 
Thaer, plant breeding, 437 
selection, 288 
Theory of error, 44 
of evolution, de Vries’, 282 
of multiple factors in size inheritance, 185 
of reduplication in linkage, 126 
Thomson, acguired characters, 481, 491, 494 
heredity concept, 3 ‘ 
Tick, Texas fever, 528 
Tilia vulgaris, 365 
Timber trees, rapid growing hybrid, 365 
Timothy, breeding, 294 
remnant system, 335 
Tinged eye color in Drosophila, 156 
Tissues, in graft-hybrids, 377, 380 
Tobacco, 317 
corolla length in, 181 
crossed by humming birds, 319 
decreased vigor in some species hybrids, 230 
disease resistant strains, 418 
fasciated, 130 
graftage of, 374 
increased yield in F), 363 
mutation affecting stature, 177 
mutations in, 367 
Stewart Cuban, 368 
Tomato, 317 
chimeras, 381 
color chimera, 272 
higher yield in F'1, 362 
mutations in, 369 
nightshade graft-hybrids, 374 
practicability of using F1 seed, 363 
red cherry, 28, 29 
strain tests, 432 
tall and dwarf, 174 
wilt resistant, 415 
Tower, beetles, 261, 259, 370 
germinal variations, 30, 31 
Leptinotarsa, 248, 259 
pure strain, 259 
selection effect, 258, 260 
Tragopogon pratensis * T. porrifolius, 438 
Training, question of inheritance of, 480, 483 
Trapnesting hens, 592, 593 
Trees, ‘‘pedigreed”’ vs. recorded, 394 
rapid growing hybrid, 365 
top working poor, 391 
43 
Trial gardens, 299 
Trihybrid, 90 
ratio, typical, 93 
Triploidy, 263 
Triticum, vulgare var. fuliguosum, 412 
vulgare, sub-species, 339 
Troprolum majus < T. minus, 230 
Trotting, horses, registration of, 496 
record, reduction of, 484, 495 
Trow, linkage theory, 126 
Truncate-winged Drosophila, Altenburg and 
Muller’s, 168 
von Tschermak, rediscovery of Mendel's prin- 
ciples, 68 
Tuber-unit method in potato, 395 
Tufts, somatic segregation, 274 
Tulip, hybridization by Dutch, 287 
species and varieties, 302 
Type, building the ideal, 611 
maintaining by vegetative propagation, 386 
Types, determining ideal, 612 
difficulties in establishing, 428 
of factor interactions, 163 
originate by mutation, 386 
Tyson, York Imperial apples, 394 
Tyzzer, mice, 529 
tumors, 527 
U 
Uniformity in F; of species hybrids, 227 
Unit characters, 71, 72 
Upton, horses, 444 
Urban, alfalfa, 296 
Use and disuse, inheritance of effects of, 492 
Utilization of clonal diversity, 302 
of hybrids in breeding, 353 
of locally adapted plants, 441 
of mutations, 302, 464 
Vv 
Valk, grape hybridizer, 290 
Vanessaio, 23 
Van Fleet, chestnuts, 410 
Variability, increased on crossing selected races, 
188 
in F3 in quantitative inheritance, 186 
Variable character expression in hybrids, 149 
Variation, 1, 2, 439 
and development, 20 
and environment, 21 
bud, 385 
by recombination, 459 
caused by modifiability, 454 
by selection, 454 
complexity of, 428 
concept, 15 
defined, 3 
fluctuating, 16, 18, 32 
importance of understanding, 325 
in domestic animals, 453 
universality of, 14 
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