| dc.description.abstract | By estimate the number of genetic distance among accessions, genetic diversity
plays an important role in the adjustment of the mating or breeding of
individuals or organisms where genes are closely related in the hybrid process.
This study was conducted to determine genetic diversity among 15 Dalat tomato
varieties (Lycopersicon esculentum Mill.) using 9 simple sequence repeat (SSR)
markers and 36 morphological descriptors. The analysis of morphological
markers showed a low variation. While the cultivars were classified in three fruit
shape classes, fruits having flattened and slightly flattened shape occupied
53.33% of the collection. In contrast with limited morphological variability, the
medium values of SSR polymorphism confirmed the average level of genetic
variability among these cultivars. PCR-amplification between genomic DNA of 15
accessions and 9 SSR primer pairs yielded 8 alleles in 4 different polymorphic
loci within the tomato’s genome. Allele frequency ranged from 0.07 to 0.93 and
observed heterozygosity (Ho) varied from 0.00 to 1.00 with an average of 0.48,
thereby revealing a low degree of homozygosity in these landraces. All the
identified SSR markers were found in a range from 0.12 to 0.5 in terms of
Polymorphic Information Content (PIC), with a mean value of 0.34. Overall,
based on the statistical number of genetic distance in UPGMA dendrogram, 15
accessions were grouped into 2 main groups and 4 sub-groups. Given a higher
polymorphic level of SSR markers, SSR markers were more capable of
distinguishing landraces into distinct genotypes expressing fruit and yield
characteristics than morphological markers. Despite of the short genetic
distance, the phenotypic and genetic variation allowed the classification of a
collection of Dalat tomato varieties. This finding could be the scientifically
fundamental initiative for identification the genetic distance to support the
effective utilization of initial materials in breeding programmes to improve crop
heterosis and produce hybrids of desirable characteristics in Vietnam.
KEYWORDS: tomato, Lycopersicon esculentum Mill., genetic diversity, genetic
distance, SSR markers, morphological markers | en_US |
