Gill, B.S.Koraboyana Vijaya Kumar2019-09-122019-09-122019http://krishikosh.egranth.ac.in/handle/1/5810127472Yield improvement is the primary objective in soybean breeding. Many biotic and abiotic stresses are responsible for yield reduction of soybean. Among the biotic stresses yellow mosaic virus (YMV) is very serious disease. In India, soybean is prone to 80% yield lose due to YMV. All dominant varieties of soybean are susceptible to this disease. Therefore, the present study was planned to identify the soybean genotypes which are resistant to YMV. JS335 is centrally released high yielding variety but highly susceptible to YMV. Punjab agricultural university developed and released YMV resistant variety SL525. In this study 84 genotypes from four populations viz. F2:7, BC1F6, BC2F5, BC3F4 of the cross JS335xSL525 were screened to identify genotypes having YMV resistance from SL525 and yield and component traits from JS335. The variety JS 335 was used as recurrent parent. The study comprised of three experiments. In first experiment all the genotypes were grown at two locations viz. Ludhiana and Gurdaspur. Analysis of variance of genotypes revealed that genetic variation for grain yield and component traits was present in genotypes. Grain yield was observed to be positively correlated with number of pods per plant, days to maturity and number of seeds per pod. Path coefficient analysis revealed that number of seeds per pod, number of pods per plant and days to maturity recorded with maximum positive direct effect on grain yield. A total of 350 SSR markers were tested for polymorphism on both parents. Out of these, 64 were polymorphic and covering entire genome of 19 linkage groups except LG D1a. By using these 64 polymorphic markers recovery of recurrent parent genome (RPG) was estimated. Graphical genotyping (GGT) was done to identify the areas of introgression and RPG recovery. GGT analysis revealed that maximum RPG was recovered in linkage groups A2 and O. Maximum introgression was occurred in linkage groups C2 and L. Out of 84 genotypes, more than 80 per cent recurrent parent genome was recovered in six genotypes viz. SLJSB-3-3 (86.5%), SLJSB-3-7 (84.4%), SLJSB-3-13 (81.2%), SLJSB-3-10 (81.2%), SLJSB-2-10 (81.2%) and SLJSB-3-14 (80.9%). RPG for each population was also estimated. It was found that as number of back crosses increases, recovery of RPG also increased. Furthermore, phenotypic screening was also done to study the impact of RPG on grain yield and component characters. It was found that grain yield increased in accordance with increase in RPG. Validation experiment was conducted to identify the markers linked to YMV resistance. Out of 7 markers, 3 markers viz. GMAC7L, BARCSOYSSR_02_0547 and Satt322 were successfully validated as linked to YMV resistance. These markers can be used in MAS for YMV resistance.ennullThesis