The changes in colouration of needles, green to reddish-brown, in the fall in Cryptorneria japonica are associated with decreases in chlorophyll, with occurrence of yellowish- or reddishbrown pigments in chloroplastens. From the results of chemical investigations, these pigments were determined as α-carotin, β-carotin and xanthphyll.
In general, almost all the trees of Cryptomeria turn the dour of needles to reddish-brown (Red cloured type), but sometimes appear such individuals that needles are still green during the winter as the chlorophyll in chloroplastens remained unbroken (Green dour type).
Crossing experiments were done between these two types and following results were obtained: (1) The colouring of needles was effected by genetical control. (2) The FI progenies, arisen from Red×Red and reciprocal crossing between Red×Green were all red coloured type. Green type progenies arose only from the crossing whithin Greens. (3) These results suggested that the gene which causes the changing the colour of needles is dominant (R) and that of green colour is recessive (r); (R) probably be complete dominance as shown in Fig. 1 and Table 1. (4) Dominant gene (R) probably causes the destruction of chlorophyll in chloroplastens and as this result the colouration of needles will appear by the occurrence of carotinoid pigments, recessive gene (r) did not not causes the destruction of chlorophyll during the wininter.