666 
Nicotiana, partial sterility in species hybrids, 
238 
rustica X N. paniculata, 438 
species hybrids, 227, 228, 229, 232 
sylvestris, illustrated, 239 
tabacum, mutations in, 367 
tabacum X sylvestris, 218, 238, 244, 575 
vigor in species hybrids, 230 
Nicotine, transmission from stock to scion, 384 
Nightshade, graftage of, 374 
species hybrids, 439 
-tomato graft-hybrids, 374 
Nilsson, pedigree culture, 419 
selection, 366 
Svaléf system, 425 
Vilmorin method, 293 
Nilsson-Ehle, creating populations, 350 
duplicate factors, 137 
oats, 368 
Nomenclature, confusion in, 428 
Non-disjunction in Drosophila, 198, 204 
primary, 199 
secondary, 200 
Non-functional gametes and zygotes, 248 
Non-Mendelian inheritance, 248 
no clear evidence for, 248 
Normal curve and its significance, 34 
Norton, Jesse B., Puccinia asparagi, 415 
Norton, J. B. S., color chimera, 272 
tomato wilt, 415 
Nucleus, 59, 61, 62 
Nucleolus, 60, 61 
Nursery stock, pedigreed, 394 
recorded, 394 
Nuts, breeding disease-resistant, 410 
heterosis in, 364 
Oo 
Oak, Fi hybrids in, 365 
Oats, 317 
autogamous, 257 
Banner, 340 
Imported Scotch, 340 
Irish Victor, 340 
linkage in, 125 
little natural crossing, 318 
mutations in, 367, 371 
pure lines, 293, 340, 371 
selection of pure lines, 371 
Obrecht, mule, 516 
Observation, method of, in genetic research, 4 
CGnothera, albida, 281, 282, 285 
biennis X O. franciscana = neo-lamarckiana, 
248, 283 
brevistylis, 279, 282, 284 
crossbreeding experiments, 283 
cytological studies in, 285 
factor mutations in, 285 
genetic factors, 283, 284 
gigas, 280, 282, 285 
investigations classified, 283 
levifolia, 278, 282, 285 
INDEX 
Gnothera, lamarckiana, chromosome number 
285 
described, 276 
family pedigree, 279 
hybrid, origin of, 282 
lamarckiana ¥ O. rubrinervis, 245 
lata, 279, 282, 285 
matroclinous species hybrids, 229 
Mendelian inheritance in, 283, 285 
“‘mutations,’ 276 
nanella, 279, 282, 285 
nanella & O. rubrinervis, 245 
oblonga, 281, 282, 285 
pangens, 247 
progressive, degressive, regressive and in- 
constant species, 281 
rubricalyx, 284 
dominant mutant, 267, 270 
rubrinervis, 280, 282, 285 
rubrinervis X O. nanella, 247 
scintillans, 281, 282, 285 
seed sterility, 283 
species hybridization, 244 
Okra, dimorphic leaves, 275 
Olive chimeras, 381 
Oliver, hybridizing alfalfa, 348, 349 
Olmstead, experimental error, 430 
Orange, Australian navel, 271 
bud selection, 391 
chimeras, 375 
corrugated, 392 
performance records, 391 
ribbed, 392 
Thomson navel, 392 
Washington navel, 391, 392 
yellow navel, 392 
Organic evolution and chromosome development, 
264 : 
role of factor mutations, 286 
Organization of plant breeding, 299 
Organizations of plant breeders, 300 
Origin of Boston fern varieties, 312 
of domestic animals, 460 
varieties of plants, 302 
of sweet pea varieties, 303 
of varieties of sorghum, 370 
Ornamental trees, rapid growing, 365 
Orthogenetic variations, 20 
Orton, cotton, 417 
Fusarium niveum, 415 
potato, 416 
watermelon, 414 
Outbreeding, 583 
P 
Paelinck, stock and scion, 383 
Pangens, 246 
Parallel induction, 492 
de Parana, zebra hybrids, 570 
Paratettix, mosaic expression in, 152 
multiple allelomorphs in, 157, 160 
Parents, choice of in hybridization, 343 
culture of in hybridization, 343 
Digitized by Microsoft® 
