The effect of perennial ryegrass sowing date on endophyte presence and dry matter yield

The effect of perennial ryegrass sowing date on dry matter (DM) yield and endophyte presence in the resultant pasture was investigated in 2014. 'Trojan' perennial ryegrass with NEA2 endophyte was sown on three separate occasions (20 February, 20 March and 27 April 2014) into a Kaipaki peat loam soil in a replicated plot trial on a dairy farm near Cambridge, Waikato. The first two sowings were in dry conditions and neither showed any sign of germination until after 45 mm of rainfall on 4 April (43 days and 15 days after sowing, respectively). Endophyte infection in established plots was measured on 17 December 2014. Yield was also measured from sowing until no difference was seen between treatments, in October 2014. Percentage endophyte infection was not affected by sowing date. Establishment was significantly faster in the February and March sowings, prior to rain, and these produced ca. 2 t DM/ha more than the April sowing giving an estimated total profit advantage of $646/ha. Keywords: endophyte, Epichloë festucae var. lolii (formerly Neotyphodium lolii), perennial ryegrass, Lolium, seed storage, sowing date, NEA2

Characterisation of novel perennial ryegrass host–Neotyphodium endophyte associations

The temperate pasture grass Lolium perenne L. is commonly found in symbiotic association with the asexual fungal endophyte Neotyphodium lolii. Levels of endophyte colonisation and alkaloid content were evaluated in associations formed by plant genotypes from cv. Bronsyn with the standard endophyte (SE) and five distinct commercial endophyte strains. Bronsyn–SE produced all of the measured alkaloids (lolitrem B, peramine, and ergovaline). Bronsyn–AR1 produced only peramine, while Bronsyn–AR37 produced none of the tested alkaloids. Bronsyn–NEA2, Bronsyn–NEA3, and Bronsyn–NEA6 produced both ergovaline and peramine. Both endophyte strain and host genotype exerted significant effects on alkaloid production. Analysis of endophyte colonisation using qPCR revealed differences between each association. With the exception of Bronsyn–AR1 and Bronsyn–NEA3, host genotype also significantly affected colonisation levels. Phenotypic performance of each association was also assessed, based on measurement of morphological traits under glasshouse conditions in hydroponic culture. Significant variation due to different endophyte and host genotypes was observed. Collectively, these studies confirm that differences in both endophyte and host genotypes contribute to host–endophyte performance in a complex interactive manner.