Marker Assisted Selection for high oleic acid content in Groundnut

Abstract

newlineTwo elite Spanish bunch groundnut cultivars viz., TMVGn 13 and GJG 33 having low newlineoleic acid content from 45 50% were selected for improvement of the oleic acid content. newlineThe introgression of this high oleic trait was from a Spanish bunch, high oleic groundnut newlinecultivar Girnar 4 through marker-assisted backcrossing. Two cross combinations TMVGn 13 newlinex Girnar 4 mentioned as C1 and GJG 33 x Girnar 4 mentioned as C2 were used in this study. newlineAn assessment of diversity was done in 55 groundnut genotypes for eleven oil, kernel and newlinepod traits. The variability parameters such as mean, coefficient of variation, skewness and newlinekurtosis, principal component analysis, clustering and correlation studies were performed. newlineAmong the genotypes, Girnar 4 and NRCGHFS72 showed high mean values for oleic acid newline(gt70%) while NRCGHFS72 had the lowest value for linoleic acid (6.01%). The genotype newlineVG19817 had a high oil content of 56.27 %. The oleic acid trait showed a moderate newlinecoefficient of variation (17.7 %), linoleic acid content showed high CV (22.4%) and oil newlinecontent showed low CV (6.38%). Oleic acid had a positively skewed and leptokurtic nature newlineof distribution. Linoleic acid had a negatively skewed and leptokurtic distribution. newlineOil content had a negatively skewed and platykurtic nature of variation. In Principal newlinecomponent analysis, the first four principal components explained 78.37% of the total newlinevariation. In PC1, the traits palmitic acid, linoleic acid, stearic acid and oil content newlinecontributed positively. In PC2, the trait oleic acid had a positive weight. With the biplot newlinerepresentation, the oleic acid was found to be negatively correlated with the linoleic acid newlineand oil content. UPGMA method of hierarchical clustering based on the Euclidean distance newlinegrouped the genotypes into nine major clusters, with Cluster III having the genotypes with newlinemid (gt50%) to high oleic (gt70%) content such as Girnar4, GJG18, GJG19, ICGV191020, newlineICGV191035, K7 and NRCGHFS72. Correlation studies showed that linoleic acid had a newlinesignificant and negative correlation with oleic acid and a positive correlation with palmitic newlineacid. Oleic acid was found to be negatively correlated with the oil content. With these newlineresults, it can be concluded that the increase in the oleic acid reduces other fatty acids and newlineoil in groundnut. Hence, appropriate selection of recurrent parent with high oil content is newlineessential in the oleic content improvement programme of groundnut. newlineEfficiency of the three types of marker assay systems viz., AS-PCR assay by newlineChen et al. (2010), CAPS marker assay by Chu et al. (2007) for A genome and Chu et al. newline(2009) for B genome, Reaction primer assay by Yu et al. (2013) to identify the plants positive newlineand homozygous for both the A and B genome were tested with progenies of segregating newlinepopulation. To select the progenies from C1 and C2 allele-specific PCR primers suggested by newlineChen et al. (2010) were used for the initial screening of the plants in the F1 generation. newlineTo identify the homozygous plants in BC2F2, reaction primers were utilized for the screening newlineat later generations. Screening of the genome-wide SSR markers to estimate the parental newlinepolymorphism between the recurrent and donor parent identified 59 and 50 polymorphic newlinemarkers in C1 and C2 accounting for 13.6 and 11.7% of polymorphism, respectively. newlineBackground genome recovery of the recurrent parent was estimated. The average recurrent newlineparent genome recovery in C1 and C2 was 81.9 % and 81.3 % in BC2F2. The maximum newlinerecovery percentage in BC2F2 for C1 was 84.7 % and for C2 was 86.0%.