Nuclear DNA Content, Ploidy Level, and Chromosome Number in Turkish Okra Landraces

Molecular studies show that okra germplasm harbour narrow genetic diversity despite certain level of phenotypic variation in Turkey. However, there is a gap in the information on the cytogenetics of Turkish okra genotypes. Studies on the cytogenetics and ploidy level may provide further information on the genetic diversity of Turkish okra germplasm. This study, therefore, investigated nuclear DNA content, ploidy level and chromosome number of 26 okra landraces and 3 commercial cultivars (Akk & ouml;y-41, Kabakl & imath;-11 and Marmara-1). The 2C nuclear DNA content varied from 3.05 to 3.20 pg with mean 2C values ranging between 3.11 and 3.18. The variation in nuclear DNA content was, however, statistically insignificant. Okra had a high number of chromosomes with very small sizes. The chromosome number of the plants investigated in the study was determined to be 2n (10x)= 128 +/- 2. Based on these results, the genotypes investigated are, probably, allodehaploid with some extra chromosomes and B chromosomes. In conclusion, the Okra germplasm has a narrow base of genetic diversity in the germplasm pool, which may limit the success of future breeding programs. Suggestions are discussed to enhance genetic diversity in the germplasm for more effective breeding programs.