EFFECTS OF THE PROPAGULE SIZE ON THE TUBEROUS RHIZOME PRODUCTION AND PHYSICOCHEMICAL CHARACTERISTICS OF JERUSALEM ARTICHOKE

As a crop that is rich in oligosaccharides, Jerusalem artichoke is considered one of the most promising plants for production because of its ability to survive in marginal lands, strong resistance to biotic and abiotic stresses, ease of conversion into biofuels, and use for food consumption. In the present study, the effects of propagule size on tuberous rhizome production and the physicochemical characteristics of Jerusalem artichoke were evaluated. Five propagule sizes of tuberous rhizome, 10 g (T1), 30 g (T2), 50 g (T3), 70 g (T4), and 90 g (T5), were used in a completely randomized experiment with 5 replicates and 11 plants per replicate. Harvesting was carried out 164 days after planting. The results showed that T1 resulted in the lowest emergence rate, number of tuberous rhizomes and aboveground fresh weight per plant of all the treatments. However, there was no significant difference among treatments in the tuberous rhizome dry weight, pH, titratable acidity, Brix, or reducing sugar. Propagule with tuberous rhizome of 30-50 g is recommended to achieve a high emergence rate and yield.

Study of some demographic parameters of Bactrocera (Dacus oleae); Test of a new food attractant in a trapping method

This study focuses on the observation of changes in the demographic parameters of olive fly over time in two regions, Mitidja and Mezghana region, the method consists in identifying certain biotic and abiotic factors that can play a role on the variations of these parameters; on the other hand we tested new food attractiveness in a trapping method. The Results showed that the demographic parameters (emergence, parasitism and mortality) are influenced by the year and by the region factor with a very high emergence rate above 50%; On the other hand, the rate of parasitism remains low with a maximum value of 33.23% recorded in Mezghenna, regarding nymphal mortality the maximum value is recorded in Chebacheb with 26.44%. Furthermore, the study of the efficiency of nitrogen fertiliser (Urea 46 unit) on the catches of adults showed us that the best concentration of attraction is 6%; on the other hand, the yellow color of the traps positively influences the catches of Bactroceraoleae.