Screening timothy genotypes for nitrate reductase activity using an ELISA technique

Abstract

Timothy (Phleum pratense L.) is the most cultivated forage crop in Eastern Canada. Like most perennial grasses, ample amounts of nitrogen are needed to obtain adequate yields. A selection program to reduce the nitrogen requirements of timothy and improve its nitrogen use efficiency could be undertaken if a suitable method were developed to screen large plant populations and identify genotypes with high nitrate reductase (NaR) activity. An enzyme-linked immunosorbent assay (ELISA) using anti-barley (Hordeum vulgare L.) NaR immunoglobulin has been developed. It has been used to evaluate genetic variability for NaR activity in two timothy cultivars. Using the ELISA procedure, no significant differences in NaR activity were detected between the two cultivars. However, significant differences were observed between randomly selected genotypes within one of the two cultivars. The ELISA procedure repeatedly and accurately detected very small amounts of NaR activity. This procedure could enable the screening of large populations of timothy or other forage grasses for selection of genotypes with high NaR activity. The presence of genetic variability for NaR activity in timothy could be exploited in a selection program. Key words: Timothy, nitrate reductase, ELISA