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ARS Home » Southeast Area » Poplarville, Mississippi » Southern Horticultural Research » Research » Research Project #437110

Research Project: Karyotype Analysis of Vaccinium Species

Location: Southern Horticultural Research

Project Number: 6062-21000-010-012-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 30, 2019
End Date: Sep 30, 2021

Objective:
(i) Determine the chromosomal morphology and karyotype of 12 Vaccinium (V.) species including V. darrowii, V. elliottii, V. tenellum, V. pallidum, V. arboreum, V. stamineum, V. crassifolium, V. myrsinites, V. corymbosum, V. angustifolium, V. constablaei and V. virgatum; and (ii) determine the number of Vaccinium genome types.

Approach:
Karyotype analyses will be performed for 12 Vaccinium (V.) species including, V. darrowii, V. elliottii, V. tenellum, V. pallidum, V. myrsinites, V. arboreum, V. stamineum, V. crassifolium, V. corymbosum, V. angustifolium, and V. virgatum. Briefly, root tips will be harvested from 12 Vaccinium species and fixed in Farmer’s solution. Roots tips will be stained with Giemsa dye and chromosomes in the somatic cells at the metaphase stage will be visualized and photographed using a light microscope. For each species, at least 10 clear images in which chromosomes were separated one by one with clean cytoplasm will be used to count the chromosomes. The respective lengths of the long arm (La) and short arm (Sa) of each haploid set chromosome will be measured. The following parameters will be estimated in each metaphase image to characterize the karyotype numerically: (1) total chromosome length; (2) arm ratio; (3) mean haploid chromosome length and centromeric index. 2. Genomic in situ hybridization and Fluorescence in situ hybridization GISH will be used to determine genome types found in 12 Vaccinium species and 12 interspecific hybrids. FISH analysis will be performed to determine the distribution patterns of rDNA in each species. GISH analysis will be performed in 12 Vaccinium species to assess their relatedness. Ideograms, banding patterns, and chromosome measures of the 12 Vaccinium species will be generated and single letter genome symbols will be established.