Section 14 — Animal Genetics and Breeding 



$ An Ri x cS 4 « -Ki and °f ? 4/i wo/-/ x J An R\ 

 crosses. Presently we have 274 batches of the 

 4th allotetraploid generation, a part of which is 

 expected to yield larvae in spring. In all, from 

 1353 matings 2263 allotetraploid larvae were 

 produced; 452 were reared up to Imago stage. In 

 314 crosses An X An percentage of hatching 

 fluctuates from to 39.5 per batch; total 

 hatching making 1.0 per cent 54.3 of males proved 

 to be partially fertile. In all generations sex 

 ratio remains close to the normal one. 



To our knowledge, it is the first case of bisexual 

 reproduction of artificial allotetraploids in 

 animals. 



14.19. The Present Status of the Formal Genetics of 

 Triboiium castaneum, T. confusum, Latheticus 

 oryzae and Gnathocerus cornutus (Tenebrioni- 

 dae). Alexander Sokoloff (Berkeley, U.S.A.). 



Linkages established for castaneum: Chromo- 

 some I (=X) from left to right in the order given: 

 spotted elytra (sp); lethals 2 and 4 ( : 2, H); 

 divergent elytra (dve); lethal-3 ( 1 3); pygmy (j>y); 

 miniature-appendaged (ma); red eye (r); paddle 

 antennae (pd); truncated elytra (te); red- 

 modifier (M T ); lethal-1 ( : 1). II: pearl eye (p); 

 pink eye (p pk ); pegleg (pg). Ill: black (b); 

 light ocular diaphragm (lod). IV: Bar eye (Be); 

 sooty (s); deformed legs (dfi). V: microcephalic 

 (mc); jet(j); split (spl). VI: Microphthalmia A/o). 

 VII: blistered elytra (ble); chestnut eye (c); 

 curved appendages (ca); fused tarsi and antennae 

 (Fta); short antenna (Sa). VIII-X: Vacant. 



Unassigned: cut prothorax (cp) and juvenile 

 urogomphi (jit) (which are linked to each other); 

 fused antennal segments 1-3 (fas-l, fas-2, fas-3); 

 abbreviated appendages (aa); squint (sq); 

 extra urogomphi (eu); prothoraxless (ptl); 

 engraved metasternum (em); incomplete meso- 

 sternum ( ms); warped ely tra ( we) ; pointed elytra 

 (pe); short elytra (sh); dent (dt). 



For confusum: Chromosome I (X): Striped 

 (St); eyespot (es); labiopedia (Ip); reduced 

 antennae and elytra (rae); lethal-1. II: pearl (/?); 

 ebony-2 (e-2); pegleg (pg). Ill: black. V: ebony. 

 VI ;I blistered. IV, VI, VII, IX to be filled with 

 following: short elytra (sh); light ocular dia- 

 phragm (lod); ruby spot (rus); ruby (Ru); dirty 

 pearl eye (dpe); chestnut (c); stilted legs (stl); 

 engraved metasternum (em); dent (dt); warped 

 elytra (we); split (sp); melanotic stink glands 

 (mgs); deformed legs (di); fused antennal 

 segments (fas). 



For L. oryzae: I (X): red (r); truncated elytra 

 (te). II: pearl. Unassigned: brown body color 

 (bwb). 



For G. cornutus: II: pearl; III: light ocular 

 diaphragm (lod). 



14.20. Genetic Correlation and Asymmetry of the 

 Correlated Response from Selection for In- 

 creased Body Weight of Triboiium in Two 

 Environments. A. Earl Bell and H. W. McNary 

 (Lafayette, U.S.A.). 



Genetic parameters needed for predicting 

 direct and correlated responses from selection 

 for increased body weight (pupa stage) of 

 Triboiium castaneum in each of two environments 

 (70 per cent versus 40 per cent relative humidity) 

 were estimated in a random mating Base Popu- 

 lation. Heritabilities of body weight in the two 

 environments were not significantly different 

 (0.58 in Wet and 0.55 in Dry), but the phenotypic 

 variation in Dry was approximately twice that in 

 the Wet Environment. The genetic correlation 

 between the two traits was estimated as -f 0.98. 

 The predicted direct and correlated responses in 

 both environments were checked in a replicated 

 selection experiment spanning nine generations. 



Good agreement between predicted and 

 observed direct response was obtained for 

 each of the four selected populations. Also, the 

 average observed correlated response including 

 both environments was accurately predicted 

 (Predicted/observed = 147. 5/141. 5 ug and 139.5/ 

 138.5 |ag per generation for Replication 1 and 2, 

 respectively). Yet the observed correlated 

 response in each replication for the population 

 selected in Dry was approximately twice that 

 predicted, while those observed in the popu- 

 lation selected in Wet were only half of the 

 predicted values. 



When the realized genetic correlation, Tg, for 

 each population was calculated from the 

 observed heritabilities, direct and correlated 

 responses and phenotypic variances t 1 ), it was con- 

 cluded that the observed asymmetry of correlate 

 response was due to the effective genetic corre- 

 lations being different for the two environments 

 (rg= +0.64 and +0.67 for the two replications 

 of selection in Wet and +0.93 and +1.12 for 

 selection in Dry). 



Supported by Grant G-15824, National 

 Science Foundation. 

 1 . Falconer's Formula 2, J. Heredity 45, 42-4. 



14.21. Selection for 13-day Larval Growth in Tribo- 

 iium under Two Nutritional Levels. Yamada 

 Yukio and A. E. Bell (Lafayette, U.S.A.). 



Selection for large and small 13th-day larval 

 weight in Triboiium castaneum has been investi- 

 gated for 16 generations to evaluate the effec- 



256 



