Stem formation at alfalfa varieties and correlative dependences with some main parameters

Abstract

During the period 2006-2009 in IFC-Pleven were studied 9 alfalfa varieties: Europe, Prista 2, Prista 3, Prista 4, Obnova 10, Pleven 6, Dara, Multifoliate and Dama. In the first year of its development alfalfa formed on average 1.42 number of stems per plant. During second and third year their quantity increased to 2.14 and 3.83 number whereafter during fourth year they decreased to 3.28. In all years (except the first year) was found a trend of increase in stem number from spring to autumn regrowth with average values 2.11, 2.85 and 3.05 respectively. Average for the four-year period the greatest number of stems (over the average for the nine studied varieties – 2.67) formed the Multifoliate variety followed by Europe, Prista 4, Obnova 10 and Dama. The varieties which are characterized by less density of stand (number of plants per unit area) had a greater number of stems per plant (r = -0.530). Correlations with mean and high positive value were found between stem formation and amount and distributions of rainfall during vegetation period (r = 0.989), year of alfalfa development (r = 0.861), nodulation (r = 0.763), weight of root mass (r = 0.411) as well as correlations with mean negative value between number of stems and percentage of damaged stems by Apion seniculus (r = -0.456).