INDEX 



545 



Hybridization in evolution of maize, 175-98 



discussion, 197-98 



summary, 198 

 Hybridization and inbreeding, effects of, 



294 

 Hybridization in maize, 9 

 Hybridization tests on corn, 429-47 

 Hybridized seed corn, 42 

 Hybridizing maize and teosinte, effects of, 

 186-87 



Hybrids, 424 



adaptability of, 99-100 



barley, 301 



differences in water requirements, 106 



first generation, 165-66, 174 



first generation intervarietal, 172 



growth rates, 105 



growth requirements, 121 



intervarietal, 161 



physiology of gene action, 98-113 



pre-Mendelian, 11 



presence of iron and aluminum, 106 



response to soil conditions, 106 



Hybrids and inbreds 

 correlation between, 294 

 gene determination of variation, 292-94 



Hybrids, second-cycle, 453-54 



Hybrids and synthetics developed from 

 Celaya lines, 442 



Hypoxanthine, 109, 119 



Inbred corn, development of embryos, 104 



Inbred and hybrid corn grains, growth-pro- 

 moting activities of extracts from, 109 

 "Inbred Index," 142 



Inbred Unes, 386, 401, 403 

 of corn, 230 

 formation of, 427-31 

 for heterosis tests, 330-51 

 methods of improving, 57 

 in reciprocal selection, 347 

 recovering of, to retain advantage at- 

 tributable to heterosis, 310-18 

 of tomatoes, crossing of, 307-10 

 undesirable characters, 57 



Inbred parents, partial regression of yield 

 on yield of, 460-62 



Inbred races, genotypes for viable, lethal, 

 and recessive visible alleles, 481 



Inbred selection, 140, 163, 170 



Inbreds 



crossed, 34 



residual heterozygosity in, 31 



selfed, 34 



Inbreds and heterotic hybrids, structural 

 differences between, 112 



Inbreds and hybrids 

 correlation between, 294 

 gene determination of variation, 292-94 



Inbreeding, 161, 414 

 dangers of, 18 

 degree of, 23 



deterioration incident to, 44 

 different generations of, 63 

 early ideas on, 1-13 

 effect on growth, 81 

 effect on seed collapse in Medicago saliva, 



85-89 

 to improve cattle breeds, 6 

 injurious effects of, 17 

 reciprocal recurrent selection with, 457 

 records of, 5 



results with corn and swine, 338-40 

 in seed development, 81-97 

 too-close, 2 



Inbreeding, animal, 5-7 



Inbreeding versus crossbreeding, 7 



Inbreeding and crossbreeding effects, 81-97, 

 331-32, 350 



Inbreeding and crossbreeding maize, 12 



Inbreeding decline, 332, 341, 350 



Inbreeding depression, 297, 349 

 effect, 86 

 and heterozygosity, linearity of, 459-60 



Inbreeding effect 

 on germ plasm, 454 



on heterosis as related to defective genes, 

 481 



Inbreeding experiments of swine, results, 

 331-32 



Inbreeding, human, 2-5 



Inbreeding and hybridization, effects, 294 



Induction of polygenic mutations, 160 



Inheritance of quantitative characters, 327 



Insect galls, 118 



Interaction between alleles, 229-30 



Interaction of genes, 245 

 and cytoplasm, 232-33 



Interallelic association, 330 



Interallelic gene interaction, 63, 319, 353 



Interallelic and intraallelic interactions and 

 pleiotropy, 317-19 



Intercrossing, 420 



Intergroup selection, 151 



Interracial hybridization in maize, 176-83 



Interspecific hybridization of maize and 

 teosinte, 183-97 



Interspecific hybrids, 95 



Intervarietal hybridization, selection, and 

 inbreeding, 172 



Intervarietal hybrids, 161 



potence in, 166 

 Intraallelic association, 330 

 Intraallelic gene interaction, 353 



Intraallelic and interallelic interactions and 

 pleiotropy, 317-19 



