Breeding by In vitro Culture to Improve Tolerance and Accumulation of Lead in Cynodon Dactylon L.

Abstract

Turfgrasses are usually important groundcover plant s in many landscapes. They occupy the lowest surface of the landscape, close t o pollutant particles. So, they can be an attractive option for environmental remediation. To day, high concentrations of hazardous chemicals such as lead are among the most serious e nvironmental problems. In vitro selection of turfgrass accumulator or tolerant of t oxic ions may lead to production of plants that have better adaption to polluted sites. This study was undertaken to investigate the tolerance or accumulation potential in Bermuda grass to high concentrations of lead under tissue culture conditi on and identifying differences at the molecular level among accumulators by RAPD markers. Callus that were used for in vitro selection were exposed to different concentrations of lead in the media. After the first mowing, tolerant plantlets were evaluated for lead accumulation potential. All plants of Bermuda grass originating mainly from regeneration pathways had undergone genetic changes. The results revealed that occurrence of so maclonal variation via somatic embryogenesis and organogenesis of Bermuda grass cu lture with a frequency of 33%. Although some in vitro derived plants showed increase in uptake potential of lead in their shoots (2 times higher Pb extraction), there were s ome regenerates with decreased lead accumulation in shoot, and some varieties without a ny changes in lead uptake properties in comparison to the control. Molecular marker coul d be efficient in determining the genetic changes induced by somaclonal variation. Th e improvement of lead accumulation in lead extraction varieties indicated a successful mutation in Bermuda grass for breeding traits such as phytoremediation purpose. Keywords : Bermuda grass, Lead accumulation, Lead-RAPD.