Thirupathy Venkatachalapathy, R.DEEPA.C.N2020-07-102020-07-102011http://krishikosh.egranth.ac.in/handle/1/5810148946The aim of this study was to investigate the polymorphism of the Prolactin receptor (PRLR) and follicle stimulating hormone (FSH) beta genes present in different pig breeds and its influence on reproductive traits. Reproductive traits investigated were: Litter size at birth (LSB), Litter weight at birth (LWB), litter size at viii weaning (LSW) and litter weight at birth (LWW). Genomic DNA was isolated from blood of 63 Large White Yorkshire (LWY), 25 Duroc and 32 Desi× large white Yorkshire crossbred pigs. The PCR-RFLP method was used to detect polymorphism in PRLR and FSH beta genes. Alu I polymorphism was found in 10th exon region of PRLR with two different alleles. The frequencies of PRLR allele A were 0.52 in the LWY, 0.64 in Duroc and 0.60 in the crossbreds. The allelic frequencies for PRLR- B allele were 0.48, 0.36, 0.40 in LWY, Duroc and crossbreds respectively. Hae III polymorphisms were detected in FSH beta first intron region. Two genotypes were found leading to allele frequencies of 0.87, 0.88. 0.83 for A and 0.13 ,0.12 ,0.17 for B allele in LWY, Duroc and crossbreds respectively. FSH beta fragment covering first exon and partial intronic region showed no polymorphism with Taq I in the tested sows of the LWY, Duroc and crossbreds. The association analysis between the genotypes and the reproductive traits were estimated using Least square mixed model method. PRLR/Alu I genotype showed significant association with litter size at weaning. The AB genotype had higher LSW in all breeds. Sows with the PRLR -BB genotype had the largest litter size at birth , but the difference was statistically not significant. No significant associations of FSH beta alleles with the traits were observed. Analysis were also done to estimate the effect of sire, age, breed and season of farrowing and showed that only age has significant effect on litter traits in the population studied. Sows at an age of 1.5-2 years had higher litter size and litter weight at weaning. Additional data is needed to confirm the significant effects seen in these three lines. However, the effects observed to date suggest that PRLR/Alu I polymorphism was associated with litter size at weaning and hence could be useful as a marker for litter size in selection programs.ennullThesis