Abstract
The genetic basis of dipause of Tetranychus urticae KOCH was analyzed by reciprocal and backcrosszing experiments, using one diapausing strain (D), which exhibited nearly 100 percentage of diapause, and 4 non-diapausing strains (ND1, ND2, ND3 and ND4), which completely lacked diapause. The strains used were selected from 5 different field populations. F1 hybrids between D and ND2 exhibited more than 90% diapause regardless of the direction of the crosses, suggesting "diapause" was fully dominant. On the other hand, significant reciprocal differences were observed in the diapause incidences of the F1 hybrids between D and each of the other 3 non-diapausing strains, showing that a maternal effect is operating.The results from backcrosses usind D and ND2 suggest that "non-diapause" is not controlled by a single recessive but by multiple recessive genes.
