Frequency of B-chromosomes in Rye (Secale cereale) Cultivated in Paldang

팔당산 호밀(Secale cereale) B 염색체의 출현빈도에 대하여

Rye in Paldang was investigated with regard to the occurrence of B-chromosomes from 1963 through 1977, and frequencies of B-chromosomes were as follows; 2% (1963), 8% (1964), 8% (1965), 15% (1966), 11.5% (1968), 11.7% (1969), 20% (1975), 19.6% (1976), and 12.8% (1977). The result of the chi-square test showed statistically no significant difference between the frequency of B-chromosomes each year. The analysis revealed that distribution of B-chromosomes seemed to be relatively uniform in the rye field. With regard to the sample size 50 plants were quite enough to estimate the frequency of B-chromosomes in rye population. Quadrivalent due to translocation heterozygote were observed in the population of Paldang rye from 1966 through 1977, their frequencies being 1 to 7%. Numerical increase of B-chromosomes in rye due to non-disjunction process in the pollen as well as in the ovules was well-known phenomenon, whereas B-chromosomes tended to be eliminated in meiosis and seed fertility of rye was reduced in the individuals with B-chromosomes. The mechanism of gain or loss for B-chromosomes might support the equilibrium of B-chromosomes in Paldang rye population.

1963년부터 1977년까지 팔당산 호밀의 B 염색체의 출현빈도를 조사한 결과는 다음과 같다. 2%(1963), 8%(1964), 8%(1965), 15%(1966), 11.5%(1968), 11.7%(1969), 20%(1975), 19.6%(1976), 12.8%(1977). $x^2$검정의 결과는 각 년도에 있어서의 B'의 출현빈도 사이에 유의차가 없음을 나타내고 있다. 1976년과 1977년에는 호밀 밭을 10개 구로 나누어 재료를 수집하여 B'의 분포와 표본채취의 결과를 분석하였다. 호밀의 B'는 집단내에서 비교적 균일하게 분포되고 있으며 최소 50개체를 관찰하면 호밀 집단의 B'의 출현빈도를 대략 알 수가 있었다. 팔당산 호밀 집단에서 1966년부터 1977년까지 계속하여 전좌이형접합체(T.H)에 의한 사가염색체를 가진 개체가 1~7%의 빈도로 관찰되었다.