• Korean journal of applied entomology
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• v.31 no.4
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• pp.366-370
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• 1992

Salient chromosomal variations during the first meiotic division in primary spermatocyLes of the three brown planthopper, Nilaparvata lugens (Stal) , biotypes were observed. The meiotic index was highest in biotype 3 (58.6), followed by biotype 1 (39.4) and biotype 2 (23.6). Total chromosomal aberration including agmatoploidy, aneuploidy, loose pairings of sex chromosomes, and cytoplasmic shrinkage was found high in the order of biotype 1 (60.6%),2 (47.9 %), and 3 (38.1 %). However, percent agmatoploidy was highest in biotype 2 (19.6%) whereas in biotypes 3 and 1, it was 9.5% and 2.5%, respectively. The number of cells with isolated sex chrosomomes was observed highest in biotype 2.

• Korean Journal of Plant Taxonomy
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• v.48 no.3
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• pp.201-205
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• 2018

Carex L. (Cyperaceae) is the largest angiosperm genus in the temperate zones with more than 2,000 species worldwide. Unusual chromosome structures, called holocentric chromosomes, have been postulated to contribute to species diversity in the genus. In Korea, this genus has the greatest number of species, but chromosome information as it pertains to the taxa is mostly unknown. Here, we report meiotic chromosome numbers of five Carex taxa in Korea. The following observations are made: Carex jaluensis Kom. ($n=27_{II}$, $28_{II}$, $29_{II}$, $30_{II}$), C. japonica Thunb. ($n=28_{II}$, $29_{II}$), C. planiculmis Kom. ($n=30_{II}$), C. miyabei Franch. ($n=33_{II}$, $36_{II}$), C. neurocarpa Maxim. ($n=51_{II}$, $53_{II}$, $54_{II}$). Except for C. planiculmis, all of the species exhibit variations in chromosome numbers within individuals and/or taxa. The findings with regard to chromosome number diversity in Carex suggest that chromosome number variation (aneuploidy, agmatoploidy and/or symploidy) plays an important role in the richness of the species in the genus. Further cytological investigations are needed for a better understanding of sedge diversity in Korean flora.