Intraspecific Variations and Characteristics of Cyperus serotinus Rottb. in Kanagawa Prefecture

I. Variability among Strains in Ecological and Morphological Characteristics

Abstract

Twenty strains of Cyperus serntinus Rottb., a perennial paddy weed, were collected from 18 locations in Kanagawa Prefecture and were grown in pots for 2-3 years until 1975.
In the first study in 1976, 7 characters of each clone in relation to tuber emergence time, heading time, and shape and leaf growth were surveyed under the same growing conditions in order to analyze the variations within clones grown in a limited area (same paddy field or same waterway side) of the 18 locations.
In the second study in 1977, the following 20 characters of 20 strains from 18 locations were evaluated under the same growing conditions in order to identify variations among the strains, tuber emergence time, heading time, stalk length and diameter, leaf length and width, numer of stalks, dry leaf and stalk weight, spike and spikelet length, number of spikelets and seeds per spike, 1, 000-seed weight, tuber length and diameter, fresh tuber weight, ratio of length to diameter of tuber, number of tubers per clone, fresh tuber weight per clone and number of tuber nodes.
Results are as follows.
(1) In the first study, significant differences were recognized among the clones in each of the 7 locations, while no difference was found in the other 11 locations.
(2) In the second study, statistical analysis showed significant differences in twenty characters among twenty strains at 1 per cent level.
(3) Of all the correlations between the twenty characters observed, high correlation coefficient of over 0.80 was obtained in thirteen combinations. Particularly, there was a close correlation between the characteristics of vegetative and reproductive organs.
(4) Based on the principal component analysis, the scatter diagram of twenty strains on the axes of the first, second and third principal components suggested that all the strains could be classified into 7 groups.
(5) The existence of such intraspecific variations in this species in a similar climatic area would suggest the importance of investigations on their relation to weed control in order to improve the control measures.