Perennial ryegrass (Lolium perenne) forms the basis of grassland production in temperate pastures and is globally one of the most important forage grasses. Consequently, there has been large plant breeding industry investment over the past 40 years in producing new varieties and independent testing systems designed to identify and list those with the most improved performances. This study was conducted at the Plant Testing Station, Crossnacreevy, Northern Ireland and compared the DM yield and sward density of new varieties submitted from 1973 to 2013 and grass digestibility from 1980 to 2013, under conservation and simulated grazing managements. A variety 9 years matrix was compiled for each parameter and comparable means between varieties never in side by side performance trials were produced. Dry matter yields showed an overall significant (p \ 0.001) average annual increase of 0.52 % under conservation and 0.35 % under simulated grazing, with similar gain levels within maturity groups or ploidies. These rates were not constant over time, and periods of no gain occurred in various variety groupings. Sward density of the examined varieties did not change significantly. Herbage digestibility showed no improvement over the timeframe but had the largest differences between concurrent varieties, indicating that improvements were possible in the future. The study indicated that plant breeding gains were primarily DM yield focused with sward density remaining stagnant over the 40 years, while the lack of grass digestibility improvement appeared to only require more time to overcome. Evidence of benefits and risks of variety testing influences on plant breeding objectives was discussed.

Chemoenzymatic dynamic kinetic resolution (DKR) of rac-1-phenyl ethanol into R-1-phenylethanol acetate was investigated with emphasis on the minimization of side reactions. The organometallic hydrogen transfer (racemization) catalyst was varied, and this was observed to alter the rate and extent of oxidation of the alcohol to form ketone side products. The performance of highly active catalyst [(pentamethylcyclopentadienyl)IrCl(2)(1-benzyl,3-methyl-imidazol-2-ylidene)] was found to depend on the batch of lipase B used. The interaction between the bio- and chemo-catalysts was reduced by employing physical entrapment of the enzyme in silica using a sol-gel process. The nature of the gelation method was found to be important, with an alkaline method preferred, as an acidic method was found to initiate a further side reaction, the acid catalyzed dehydration of the secondary alcohol. The acidic gel was found to be a heterogeneous solid acid.

SUMMARYPerennial ryegrass and white clover (WC) have been shown to form compatible mixtures for pasture production under temperate climates. The inclusion of WC has the potential to enhance the performance of grass swards, but the extent of the improvement under contrasting grazing management strategies is unclear. Grazing rotation and fertilizer nitrogen (N) use have been identified as two major factors that can influence the performance of grass–clover swards. The objective of the current study was to examine the effect of differing grazing rotation lengths and the level of N application on the dry matter (DM) yield performance of grass–clover and grass-only swards as well as on WC productivity and persistency under animal grazing. Swards were managed by N application and grazing rotation length: High-N swards were managed on a 21-day grazing rotation (Man 1) and low-N swards were managed on a 30-day grazing rotation (Man 2). The four treatments were: 250 kg N/ha without WC (HN−C), 250 kg N/ha with WC (HN+C), 100 kg N/ha N without WC (LN−C) and 100 kg N/ha with WC (LN+C). There was a significant management × WC interaction over the 3 years for annual DM yield. The LN−C swards produced lower DM yield (−1917 kg DM/ha) than the swards of the other three treatments (11 167 kg DM/ha). Management had a significant effect on annual DM yield with Man 1 swards yielding 801 kg DM/ha more than Man 2 swards (10 288 kg DM/ha). The inclusion of WC yielded significantly more annual DM yield (+1009 kg DM/ha) than grass-only swards. Notably, LN+C produced the same annual total DM yield as swards under High N and a 21-day grazing rotation. Total WC DM yield and proportion across the year was altered significantly by management. Higher N fertilized swards at shorter grazing intervals had a lower WC DM yield (−1544 kg DM/ha) and proportion (−0·13). Dry matter yield of WC with low N application can be similar to that at high N levels if rotation length is used as a mechanism to determine grazing timing. Variations in WC productivity into the final year of the experiment indicate that persistence of significant contributions to DM yield by WC under low N at longer grazing intervals remains unclear after 3 years.

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