GENETIC STRUCTURE OF THE SHEEP FROM THE BULGARIAN DAIRY
SYNTHETIC POPULATION ON THE EXPERIMENTAL FARM
OF THE AGRICULTURAL INSTITUTE IN SHUMEN
Nevyana Stancheva, Jivko Krastanov, Teodora Angelova, Georgi Kalaydhziev, Daniela Yordanova, Stayka Laleva
Agricultural Institute, 9700 Shumen, Bulgaria
nevqna_68@abv.bg
Objective of the study was to establish the present generated genetic structure in the sheep from the nucleus herd of the Bulgarian Dairy Synthetic Population on the Experimental Farm of Agricultural Institute – Shumen. Subject of study are the ewes borne during the period 2007–2012 with available records for the main selection traits – milk yield and prolificacy. On the basis of the information from the pedigree books was build up a database of the pedigrees of 601 ewes. For each individual was constructed a genetic code representing the breed belonging of the ancestors back to third pedigree level. The established genotypes are formed with the participation of the breeds: 1 – Bulgarian Dairy Synthetic Population; 2 – Lacaune; 3 – Chios; 4 – East Friesian; 9 – with unknown pedigree. For the particular period of study, the genetic structure of the herd is formed by 33 genotypes. The highest portion of 78.21% is that of the ewes produced by linebreeding, shared by the BDSP genotype (53.91%) and those with genetic component from EF (24.3%). The F1 crossbreds with Lacaune and Chios (9.99 and 3.33%), the genotypes of the offspring resulted from them after mating with BDSP rams (2.16, 1.16 and 0.33%), and those of unknown pedigree from the side of one of the parents (1.83%) do not affect the overall genetic structure of the herd. With regard to the degree of grading from the different breeds, there are 15 genetic groups formed in the herd. The established variability of genotypes and genetic groups is to be grounded on the principle of forming the scientific hypothesis for evaluation of the genetic effects – additive and non-additive. Disregarding the non-additive genetic component in the process of crossbreeding would result in biased estimate of the genetic variability and in wrong prediction for the further development of the genetic structures of the population.
Keywords: sheep; Bulgarian Dairy Synthetic Population; genotype; genetic structure; genetic group
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