Agroecological Assessment of New Bulgarian and Macedonian Cotton Varieties

The aim of this reaserch was to assess new Bulgarian and Macedonian cotton varieties under different ecological environments and to establish which of them are the best for introducing into production. The research included the newest Bulgarian and Macedonian cotton varieties. In 2008-2009 in thе Field Crops Institute in Chirpan Bulgaria and Agricultural Faculty in Strumica to the Univercity Goce Delchev in Stip Macedonia field trials were carried out according to the adopted cotton growing technology in each country. The varieties were evaluated on the grounds of the obtained data for the most important economic traits. It was found that during the years of study in Bulgaria and in Macedonia, there was sufficient temperature sum and insufficient rainfall supply for cotton development. The region of Strumica was comparatively arid than that of Chirpan, but the longer growing season allowed the use of rainfall during the months of August and September, and seed cotton yield was almost twice higher. Of the studied factors varieties, regions and years the regions had the biggest share in the total variation of the seed cotton yield 73.2 % and boll weight, while the varieties had the biggest share in the total variation of fiber length and lint percentage 44.5 % and 44.4 %, respectively. The effect of years was significant only for boll weight and fiber length. In Strumica the varieties differed more strongly in seed cotton yield and fiber lint percentage and more slightly in fiber length. Based on the average two-year data, for the conditions of Bulgaria, the varieties Darmi, Helius and Natalia proved to be the best and in seed cotton yield 2233 kg.ha-1 exceeded the standard variety Chirpan-539 by 16 to 62 g.kg-1. Darmi and Natalia varieties surpassed the standard in fiber length by 1.1-1.9 mm, but were inferior to it in lint percentage. Under the conditions of Chirpan the Macedonian variety 5140 was inferior to the standard in seed cotton yield by 48 g.kg-1 and in lint percentage by 2.6 %. For the conditions of Strumica - Macedonia the Bulgarian varieties Helius, Natalia and Vega were found to be the best. The variety Helius in seed cotton yield significantly exceeded the standard by 277 g.kg-1 and the Macedonian variety 5140. Natalia and Vega varieties in seed cotton yield exceeded the standard by 225 g.kg-1 and 186 g.kg-1 and the Macedonian variety. Both varieties had longer fiber. Average for the two regions and two years the highest yield was obtained from the variety Helius - 3895 kg/ha-1, an increase of 198 g.kg-1 over the standard variety Chirpan-539, and it was followed by Natalia - 3762 kg.ha-1 and Vega – 3639 kg.ha-1, or 154 g.kg-1 and 119 g.kg-1 above the standard. The variety Natalia outlined by the longest fiber, Chirpan-539 distinguished by the highest lint percentage.