https://unilib.phaidrabg.rs/o:7553 ISSN: 0351-9147 Marović, Radovan Grbović, Branislava Petkov, Naum Mladenov, Georgi application/pdf 2071131 bytes info:eu-repo/semantics/article In the spring of 1990 four silkworm hybrids, obtained from the Experimental Station for Sericulture, Vraca, S. R. of Bulgaria were reared in the Institute of Forestry and Wood Industry, Belgrade. The hybrids were designated, as follows: 157k x Super 1 (1); Super 1 x 157, (2); Super 1 x Hesa 2 (3) and Hesa 2 X x Super 1 (4). On the basis of the obtained data the following conclusions can be drawn: - All four hybrids, fed with domestic white mulberry leaves from Banat (vicinity of Vršac), were successfully reared. - The caterpillair mortality of the hybrids under (2) and (3) was very low, within the limits of the standards, while under (1) and (4) it was a little higher than the standards (3--4%). - The weight of cocoons, silk coverings and yield of cocoons were lower for 20-27% than the standards. The reason for that can be poorer quality of leaves or reduced quantity of leaves given to caterpillars. It is possible that hybrid mulberry leaves (especially created for feeding silkworms, which leaves were used to feed the standards) are more suitable for rearing silkworms, so it should be necessary to introduce and propagate mulbery hybrids. - The hybrid S1 x H2 (3), according to this investigation, was the most successful, but the remaining three hybrids were not much lagging behind the best one, so they can be recommended to be bred in our country. Institut za šumarstvo srp Zbornik radova Instituta za šumarstvo number: 34-35 startpage: 117 endpage: 123 All rights reserved 1991 UPOREDNA ISTRAŽIVANJA UVEZENIH HIBRIDA SVILENE BUBE PRI ISHRANI LISTOM DOMAĆEG DUDA COMPARATIVE STUDY OF INTRODUCED SILKWORM HYBRIDS FED WITH LEAVES OF DOMESTIC MULBERRY