Studies regarding the performance of some bluegrass and ryegrass varieties used in lawns under the climatic conditions in the forrest steppe of North - East Romania

Abstract

The turf varieties sold in Romania are breeded in foreign countries that are different in terms of climatic conditions, and may not always perform as well in conditions of extreme drought and heat that often occurs in the summers of eastern Romania. From this point of view, trial testing of imported turf varieties in this part of the country or another, throughout the country, would be a necessary and positive research especially if it would be achieved before selling these varieties on the romanian market, thus pleasing the quality demands of the public and also helping the breeders to optimize the range of varieties for specific areas. In this research we had the chance to test by trial, for a period of two consecutive years, seven varieties of kentucky bluegrass (KB) and three of perennial ryegrass (PR) breeded in the USA, the world market leader in turfgrass varieties. Field trials were started at a farm located nearby the city of Iasi, in 2005, consisting in randomized plots replicated three times for statistical interpretation of the data. The soil was a chernozem soil type. Each plot had an area of 4 m2. Seeding rate was 15g m-1 for bluegrass varieties and 30g m-1 as recommended by the breeding companies. The weather conditions in the area are quite rough for turfgrasses, with 520 mm of rain annualy and an annual mean temperature of 9.60C. The evaluation of turgrass overall quality was done using the visual rating scale used by the National Turfgrass Evaluation Program from USA. This organization is well accepted in more than 30 countries around the world, and the rating scale is used by most of the turfgrass breeders. Following results we learned that ryegrass quality is affected by the prolonged lack of water in a higher percentage than bluegrass, by comparing the quality ratings of these two varieties over a period of two years, correlated with the climatic conditions from the same time period. The monthly ratings were used to calculate the annual mean quality rating for each individual variety, and the best quality was observed in the year 2006, for varieties: Nudestiny rated 6.5, Liberator rated 6.2 and Impact rated 6.1, all three belonging to Poa pratensis species. This study proves the importance of trial testing of imported turf varities because of the following reasons: there are large differences between turfgrass species in terms of turf quality influenced by climatic conditions but also there are differences betwen varieties that belong to the same botanical species, as we have seen in the seven bluegrass varieties studied.