Studies on Mentha spicata. L. var crispa BENTH. (Genome analysis in Mentha. Part 1)

Abstract

Two strains of Meletha sptcata L. var. crispa BENTH. (crisp mint) grow wild in our country. The one is the strain with 48 shromosomes and the other with 54 chromosomes in somatic cells. There can be found no difference between them morphologically and the one can hardly be distinguished from the other, except for the difference in the number of chromosomes. So the authors tried to analyse the genomes of two strains of M. spicata var. crispa, using M. rotundifolia as an analyser which is one of the species with the least number of chromosom es in the genus Mentha and which is presumed to be a monogenomic diploid species with genome R. The chromosome configurations at MI of PMC's in F1's are shown in table 6. Genome for mulae RR-SoSo+a1a1a2a2a3a3 and RRScSe were given to the strains of M. spicata var. crispa with 54 and 48 chromosomes respectively. Here, R and Sc are genomes, each composed of twelve chromosomes the former being common to M. rotundifolia and the latter being peculiat to M. spicata var. crispa. While a1, a2 and a3 are supernumerary chromosomes which are semi homoogous and can canjugate with one another autosyndesistically. These chromosomes are presumed to be similar to B-chromosomes which are seen in some cereals, for instance, corn, rye, etc. Hitherto, M spicata var. crispa has been considered to be a naturaliged cariety which had been introduced from Europe. But nothing has appeared in the European literature about this variety. Recently, the authors received a clone of wild mint which had been brought back from Bhutan by S. NAKAO who had travelled there in 1958. This mint was found to be M. spicata var. crispa itself with 48 chromosomes in the somatic cells. So the authors connot frankoy accept the idea that the crisp mint is a cariety of European origin. They suggested that it was required to assumi a cautious attitude to determine the original habitat og this mint.