Estimation of Nuclear DNA Content and Determination of Relationship Between Altitude and Genome Size of USDA Turkish Oat (Avena spp.) Collection

Abstract

Crop improvement is an important approach to overcome challenges raised from future uncertainties of agricultural systems and growing human population. The fundamental need for such improvement efforts is the availability of well characterized plant germplasm with sufficient genetic diversity. The 2C DNA is defined as the nuclear DNA content of an unreplicated diploid cell (in G1 phase) and is used both to get an estimate of genome size and ploidy level. Flow cytometry provides accurate and fast estimation of the genome size of plants. The genus Avena belongs to Poaceae (Gramineae) family and includes approximately 30 species including common oat (A. sativa). There are 837 Avena accessions in the USDA (United States Department of Agriculture) Germplasm Resources Information Network (USDA-GRIN) collected from Turkey. This also is the largest ex situ Avena collection from Turkey. However, initial genomic characterization of the collection has not yet been conducted. We estimated genome sizes and determined ploidy levels of Turkish oat collection. Nuclear DNA content of accessions ranged from 25.66 to 26.56 pg for A. sativa, from 25.48 to 26.88 pg for A. sterilis and from 24.85 to 26.41 pg for A. fatua. The average and range values for all three hexaploid species were in a similar close range. The range for putative tetraploid accessions belonging to A. barbata was from 12.79 to 16.90 pg. We found a number of aggregates. Furthermore, there was a negative correlation found between altitude and genome size. Obtained results will help to better utilize Avena collection in breeding efforts.