Related Experiment Video
Updated: Apr 5, 2026
Field Identification of Matricaria chamomilla using a Portable qPCR System
Published on: October 10, 2020
Chromosome number and ploidy level of balm (Melissa officinalis)
J Kittler1, O Schrader1, U Kästner1
1Institute for Breeding Research on Horticultural Crops of the Julius Kuehn Institute (JKI), Federal Research Centre for Cultivated Plants, Erwin-Baur-Str. 27, Quedlinburg, D-06484 Germany.
Background:
Lemon balm (Melissa officinalis L.) is of increasing importance resulting in rising growth area. Improved knowledge on the genome structure, number of chromosomes in connection with the taxonomical structure of balm is indispensable for improved new varieties.
Results:
A collection of 40 balm accessions (M. officinalis) was characterized by flow cytometry and FISH (18/25S and 5S rDNA) to determine the chromosome number and ploidy level. Three different types were found: diploid genotypes with 2n = 2× = 32 chromosomes; tetraploid 2n = 4× = 64 chromosomes and triploid 2n = 3× = 48 chromosomes. A haploid base number of × = 16 chromosomes is likely. First time described triploid accessions are sterile but cytologically and morphologically stable for many years. Triploids express better winter hardiness and regeneration after harvesting cuts as well as bigger leaves and internodes.
Conclusions:
A basic chromosome number of x = 16 is reported for the first time for the species M. officinalis.
Related Concept Videos
01:17Karyotyping
02:04Polytene Chromosomes
02:46Chi-square Analysis
The chi-square test was developed by Pearson in 1990.
The first step of performing a Chi-square analysis is to establish a null hypothesis, which assumes that there is no real...
01:20Monohybrid Crosses
02:27Trihybrid Crosses
Some of Mendel’s crosses examined three pairs of contrasting characteristics. Such a cross is called a trihybrid cross. A trihybrid cross is a combination of three individual monohybrid crosses. For example, plant height (tall vs. short), seed shape (round vs. wrinkled), and seed color (yellow vs. green).
The F1 generation plants of a trihybrid cross are heterozygous for all three traits and produce eight gametes. Upon self-fertilization, these gametes have an equal...