Allium subhirsutum Diploids in Croatian-Adriatic Populations

Izvršena je kariotipska analiza populacija vrste Allium subhirsutum L. sekcije Molinm G. Don ex Koch s jadranskog obalnog područja u Hrvatskoj. U svim slučajevima dobiven je diploidni broj kromosoma, 2n = 14 s kariotipskom formulom 12 m + 2 sm ili lom + 4 sm kromosoma koji u regularnoj mejozi formiraju bivalente, n = 7.Allium subhirsutum L. species of the section Molium G. Dor ex Koch is very common in the Mediterranean region of Croatia on the Adriatic Littoral. Forty plants from eleven populations coming from this area were studied. All these plants are diploids whose karyotype contains 2n=14 chromosomes. A karyotypic analysis of the number, size and shape of chromosomes has revealed the following: The chromosome number 2n=14 of this diploid is stable. The expected triploid 2n = 21 and tetraploid 2n = 28 were not found. The range of the size of chromosomes, from the shortest to the longest, was 8.05—12.53 pm, and standard deviation, both for the longer and the shorter arm, did not exceed 1 pm. The values, apart from the ones given, can be slightly higher or lower (i.e. the karyotype longer or shorter), however, the difference between the shortest and longest chromosome is ±4.5 pm. The shape of the chromosomes is metacentric and submetacentric. The former predominate over the latter and in 40% of mitoses the karyotype formula is 12m+2sm, while in 60% of them 10m+4sm chromosomes. In each karyotype there are two submetacentric nucleolar chromosomes, known as the »neapolitanum« type, which are not the shortest in size in the regressing series of chromosomes. The haryotype is generally very stable, which is also reflected in the normal course of meiosis. The meiotic chromosomes are bivalent, n=7, ring-shaped and rod- shaped in metaphase I., and during the entire course of meiosis they behave regularly forming nuclei (of pollen) without chromosome fragments. In short, all the studied karyotypes of Allium subhirsutum from eleven populations of the Mediterranean region of Croatia are mainly homomorphic (uniform), stable and of a high degree of symmetry, which are preconditions for a regular, bivalent formation in meiosis. The karyotype studied is similar to the karyotype of foreign populations, and this study provides a supplement to the data for the Mediterranean region of Croatia