COMPARATIVE INVESTIGATIONS WITH SOME DOMESTIC AND INTRODUCED SMALL LEAVE TOBACCO VARIETIES PRODUCED IN PELAGONIJA REGION

Abstract

Field experiments were carried out on two localities, in Prilep, exactly on experimental field of the Institute and in v. Dobrushevo. The influence of different nitrogen rates upon quantitative and qualitative characteristics of the four oriental tobacco types: Prilep P-23, Prilep P-79-94 (domestic varieties), and Basma1 and Elenski 817 (introduced varieties) was investigated. Investigation included four varieties, three nitrogen rates (0, 20, and 30 kg/ha) and constant amount of phosphorus (60 kg/ha) and potassium (40 kg/ha). Soil preparation was performed with one autumn (30 cm depth) and two spring plowings (8-20 cm depth). Before the trial was set up, the soil was tested to determine its agrochemical and physical properties. Fertilization was done using inorganic mineral fertilizer NPK and 27% KAN. 50% of the nitrogen amount was applied in the last plowing, prior to planting, together with phoshorus and potassium, and the rest 50 % were applied on the first hoeing. All necessary agro-technical and plant protection practices were applied during the vegetation period of tobacco. From the results, it can be noted that yield increase correlates with the increase of nitrogen quantities, in the both localities. In the Prilep locality, fertilized varieties with the 30 kg N/ha had yield increase of 24.50% and 27.23% respectively, as opposed to the control. The highest yield is noted to the P-23 variety (3443 kg/ha), and the lowest to the Basma 1 variety (2567 kg/ha). The same legality is noted in the Dobrushevo locality, where yield increases of 24.14%, 26.75%, 23.57% and 24.29 % respectively, as opposed to the nonfertilized variant. The variety Prilep P23 as standard, fertilized with the 30 kg N/ha achieved the highest average yield per unit area (3573 kg/ha), while the Basma 1 variety have significantly lower average yield than the standard variety, 2676 kg/ha. The fertilization has a positive effect and statistical significance on the average yield and gross income, per unit area. The average purchase price of tobacco, expressed in % of quality classes, has a slight decrease with increasing nitrogen rates, in all investigated varieties. In the both localities, in all investigated varieties was observed increasing content of nicotine, total nitrogen, proteins and mineral matter, and decreasing content of the soluble sugar with increasing nitrogen quantities. To evaluate the fertilization effect on investigated varieties all results were statistically processed by analysis of variance and LSD test. Based on the obtained results it can be concluded that due lower yield and gross income per ha, the introduced varieties Basma 1 and Elenski 817 are not perspective varieties for wider production in the Pelagonija region.