Study on floral behavior of selected ten cultivars of true cinnamon Cinnamomum verum (Presl.), Syn. C.zeylanicum (Blume)

Abstract

Cultivated cinnamon {Cinnamomum verum (presl)); which belongs to family Lauraceae, is the 4th largest plantation crop in Sri Lanka at present. Its propagation is mainly carried out by seedlings. Since it is showing protogynous dichogamy in nature, cross pollination can only be observed and almost all seedlings are heterogeneous. Lack of ample information on floral biology is one of the major drawbacks of mixing required characters through hybridization. Therefore this study was conducted at Cinnamon Research Station during 2007 - 2008 to study the floral behavior patterns of selected ten cinnamon cultivars of CRS 351, CRS 166, CRS 156, CRS 23, CRS 201, CRS 83, CRS 317, CRS 184, CRS 318, and CRS 40. Four flowering branches from each ten cultivars were selected and floral structure, time sequence of flower opening and closing, sexual stage of the flower were recorded during one hour interval within one week and behavior pattern was illustrated graphically. In cultivated cinnamon, there are 3-4 main vegetative flushes per year and one of them is just prior to flower bud initiation. Flowering period within an inflorescence lasts about 14 days. This time period doesn’t vaty with the cultivar. Plant showing protogynous dichogamy has two types of floral cycles, namely type A and type B. In type A cultivars have their first or female opening in the morning, perhaps about 6.30 a.m. to noon. The second or male opening is at the afternoon of the following day, in type B cultivars first opening is the afternoon and second opening is following day morning. Therefore total flower open time span is about 12 hours, according to the observations were made, CRS 40, CRS 201 and CRS 83 are type A plants and CRS 184, CRS 318, CRS 156, CRS 317, CRS 23, CRS 166 and CRS 351 are type B plants. Therefore controlled pollination between these two groups is greatly achievable. In type A plants, overlapping of male and female stage flowers can be seen during 11.00 a m. - 12 noon. In type B plants this overlapping period is during 12 noon - 1.00 pm . while CRS 83, CRS 40, CRS 156, CRS 317 and CRS 318 exhibits clear overlap of male and female stage flowers, CRS 201, CRS 166 and CRS 351 showed distinct spatial separation of male and female stages.