Subject Index 



595 



Triplo-X, 424 



Trisomic ratios, 421, 4^2 



Trisomies, 416, 417, 418, 419, 420, 

 421, 422, 423, 424, 425, 426, 

 428, 429, 430, 442 

 primary, 423, 440 

 secondary, 423, 429 

 tertiary, 423 



Triticale, 459, 4^0 



Triticum, awn t^'pes of, 322 



color of fruit of, 331, 336, 342, 464 

 interspecific crosses in, 465 

 number of chromosomes in, 11 

 stomatal size in polyploids of, 450 



Triticum X Aegilops hybrid, 461, 

 465 



Triticum compactum, 464 



Triticum dicoccoides, 464 



Tnticum dicoccum, 464 



Tnticum durum, 464 



Triticum vionococcum, 435, 464, 465 



Triticum, persicum,, 464 



Triticum polonicum, 464 



Triticum spelta, 464 



Triticum turgidum, 464, 465 



Triticum vulgare, 435, 437, 464 



Triton taeniatu^s, 437, 4'^2 



Triturus sim,ilans, 4'^ 2 



Trituru^ pyrrhogaster, 438, 4^5, 4^2 



Triturus viridescens, 442, 450, 472 



Trivalent configuration, 417, 4^8, 

 419, 4^2, 437, 441, 446, 447, 

 453, 459, 463, 467, 468 



Tropaeolum, 317, 318 



Tryptophane, 308, 309 



Tube nucleus or cell, 51, 52 



Ultraviolet light and mutation rate, 



241, 260, 261 

 Unisexual flowers, 503 

 Unit characters, 23-26 

 Univalent chromosome, 415. 416, 



417, 423, 434, 436, 437, 441, 



442, 453, 456, 459, 460, 462, 



463, 465, 471, 477 

 Unstable genes, 236, 239, 240, 241, 



259 



Unstable genes (continued) 



effect of other genes on, 241, 259 

 Uvularia, 528 



Vacuole, 3, 4 

 Variation, 362, 516 



within inbred lines, 369, 370 

 Vegetative propagation, 66, 141, 142, 



235 

 Vitamin, 305, 314 



W chromosome, 69, 70, 481, 483, 484 

 Wasp, 67. 502 

 Wheat, see Triticum 

 Wheat-rye hybrids, 459, 460 



X chromosome, 68, 69, 70, 71, 72, 73, 



77, 134, 154, 481, 482, 483, 496, 



497, 505, 506, 507, 508, 509 

 behavior of at meiosis, 71, 72 

 deficiencies in, 391 

 elimination of in Sciara, 489, 490, 



491, 492 

 genes on, 70, 95, 96 

 heterochromatin in, 222, 223 

 heteropgenosis of, 486, 487, 488 

 induced lethal mutations in, 251- 



254 

 nondisjunction of, 424, 426, 498 

 ratio of to Y chromosome, 507, 



508 

 Xenia, 443 

 X-rays. 14, 27, 77, 191, 471 



and deficiencies, 392, 393, 394, 395 



and inversions, 394, 399 



and mutations, 241. 243, 244, 245, 



248, 260, 268, 314 

 and reciprocal translocations, 203, 



404 

 and translocations, 403 

 breaking chromosomes by, 219 

 effect of on crossing over, 167 

 relation of dosage to mutations, 



244, 245, 268 



Y chromosome, 68, 69, 70, 71, 73, 77, 

 154. 481, 483, 505, 506. 507, 

 508, 509 



