BIOCHEMICAL CHANGES IN LUCERNE ATTACKED BY LONGHORN BEETLE AND ROOT ROT

Dimitriya S. PETKOVA, Evgeniya D. ZHEKOVA, Anna V. ILIEVA, Iliana I. IVANOVA

Abstract. Eight alfalfa genotypes were investigated at IASS “Obraztsov chiflik”–Rousse during the period 2006–2009. The objective of the study was investigation of biochemical changes in alfalfa roots, attacked by lucerne longhorn beetle (Plagionotus floralis Pall.) and root rot. Biochemical analysis of healthy roots, roots damaged by larvae of longhorn beetle, roots attacked by root rot and green mass were made. The healthy status of roots was evaluated according to the scale of Lyubenets and Shtukina (1968). A moderate negative correlation was determined between total phenols and sugars in plants damaged by longhorn beetle. The content of proteins, fiber, calcium, magnesium and total phenols in plants damaged by longhorn beetle and root rot increased compared to healthy ones and a decrease of sugars was observed. The highest number of healthy plants and high productivity were registered in Synthetic population (SP) N 7 and it could be appropriate in selection for the purposes of breeding.

Keywords: alfalfa, Plagionotus floralis, root rot, biochemistry

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PRODUCTIVITY OF ALFALFA GERM PLASMS. NEW DATA ABOUT ALFALFA ROOT LONGHORN BEETLE (Plagionotus floralis Pall.)

Evgeniya D. ZHEKOVA, Dimitriya S. PETKOVA

Abstract. During the first ten years of the new century a strong attack on alfalfa (Medicago sativa L.) was observed by the considered as economically insignificant alfalfa root longhorn beetle (Plagionotus floralis Pall.). The investigation was carried out in competitive variety experiment with 8 entries–7 new germplasms and the standard Prista 2 variety. The productivity of the alfalfa germplasms was determined during the period 2006–2009, including dry matter yield and yield of seeds. Number of green branches per plant; thickness of the root neck (mm), air–dry weight of the green mass (g) and number of moves and larvae of alfalfa root longhorn beetle were registered. There is a close correlation between dry matter yield, number of plants, diameter of root neck and number of moves and larvae of alfalfa root longhorn beetle. Number of larvae and moves of the pest could be more than one in one and the same root.

Keywords: Plagionotus floralis, larvae, moves, alfalfa productivity

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