Greenhouse Evaluation of Agronomic and Crude Oil‐Phytoremediation Potential among Alfalfa Genotypes

Abstract

AbstractPhytoremediation is an effective, non‐intrusive, and inexpensive means of remediating soils contaminated with organic chemicals. Different plant species have different remediation capabilities, so intraspecies variation may also exist. If intraspecific variation exists and is heritable, population improvement for performance in and phytoremediation of contaminated soils should be possible. The objectives of this study were (i) to determine if variability exists among alfalfa (Medicago sativa L.) genotypes for agronomic performance in and phytoremediation of crude oil‐contaminated soil and (ii) to determine the effect of contaminated soil on the agronomic performance of alfalfa. In one greenhouse experiment, 20 genotypic clones were transplanted into 20 g kg−1 crude oil‐contaminated soil. After 1 yr, differences existed among genotypes for total forage yield (P < 0.05), maturity at harvest (P < 0.001), plant height (P < 0.01), and phytoremediation potential (P < 0.001). Degradation rates ranged from 33 to 56% among genotypes with 46% for the unvegetated control. Two genotypes had significantly greater degradation rates than that of the unvegetated control. In a second greenhouse experiment, eight genotypes from the previous experiment were compared with their clones in uncontaminated soil. After 1 yr, mean total forage yield in contaminated soil was 32% of the yield of the same clones in uncontaminated soil. Plants in contaminated soil also matured later and were shorter. Genotype variability was present for all traits but not on all evaluation dates. The results indicate that overall agronomic performance is reduced in contaminated soil, but variability exists among genotypes for growth in and phytoremediation of contaminated soils.