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Abstract. The investigation was conducted at IASS "Obraztsov chiflik"-Rousse during the period 2009-2011. Bulgarian and foreign germplasm was the object of study. The objective of the present investigation was to isolate and identify the causes of root rot in alfalfa and to determine the reaction of local and foreign germplasm to the agent. Isolation of the pathogen was performed on KDA and Chapek nutritive medium. Positive results were reported in all germplasm observed. Attack was the lowest in annual plants.

Forage productivity and quality are the most significant traits of alfalfa (Medicago sativa L.). The objective of that study was to compare the photosynthetic properties of some trifoliolate and multifoliolate alfalfa genotypes. Plants were selected at the Institute of Agriculture and Seed Science "Obraztsov chiflik" -Ruse. MF23 multifoliolate alfalfa line and the two trifoliolate ones with high and low productivity and standard variety Prista 2 were investigated. The studied fluorescence parameters indicate the lack of differences between low and high yield alfalfa trifoliolate populations irrespective of their different productivity, while MF23 shows enhanced PSII down-regulation, which relates to a higher potential to adjust MF23 to environmental changes. Better adjustment to the environment is one of the factors that determine higher productivity of MF23 in comparison to multifoliolate alfalfa plants studied previously.Key words: multifoliolate alfalfa, photosynthesis, chlorophyll a fluorescence 1013 Introduction. Alfalfa or Lucerne (Medicago saliva L.) is one of the most important species among forage crops. Forage productivity and quality of the alfalfa (Medicago sativa L.) leaves are the most important traits of the crop [ 1 ]. Multifoliolate (MF) alfalfa cultivars characterized by four or more leaflets per leaf rather than by three, have been marketed for greater nutritive value and intake potential than standard trifoliolate (TF) alfalfa cultivars [ 2, 3 ]. Alfalfa forage quality might be improved by increasing the proportion of leaves to stems [ 4,5 ]. According to these authors [ 4, 5 ], the higher leaf/stem ratio in multifoliolate plants has not been consistently associated with improved forage quality. A MF genotype developed for superior herbage quality had leaf concentration, forage quality, and intake potential similar to TF genotypes. Multifoliolate alfalfa genotypes have the potential to produce higher quality herbage than some TF types.The productivity of MF alfalfa is an object of discussion and requires improvement in the breeding practice. Herbage yield of multifoliolate populations has previously been equal to or less than that of trifoliolate cultivars under spaceplanted conditions [ 6 ]. The authors indicate that the slight yield reduction of multifoliolate plants might be due to inbreeding depression associated with population development. In Bulgaria the first multifoliolate alfalfa variety was created in 1999 [ 7 ] and the breeding work with native multifoliolate genotypes was conducted at the Institute of Agriculture and Seed Science "Obraztsov chiflik" -Ruse.The productivity of plants is closely related to their photosynthetic characteristics. The objective of the study was the photosynthetic properties of some trifoliolate and multifoliolate alfalfa genotypes with different yield potential to be compared.Material and methods. Plant materials. Standard Prista 2 trifoliolate variety and populations B-19 and 5R-82 with higher and lower forage productivity respectively and MF2...