The recessive adult plant resistance (APR) gene Lr48 in wheat was tagged with flanking random amplified polymorphic DNA (RAPD) markers. Markers S336 775 in coupling and S3 450 in repulsion with Lr48 were identified in wheat line CSP44. Tests of these markers on available Thatcher near-isogenic lines (NILs) detected the likely presence of Lr48 in TcLr25. A test of allelism of APR involving the cross TcLr25 9 CSP44 indicated that Lr48 was present in both lines. A separate experiment on inheritance of resistance in an F 2 population of TcLr25 9 Agra Local confirmed the presence of a dominant seedling resistance gene (Lr25) and a recessive APR gene (Lr48) in TcLr25. This study demonstrated the value of molecular markers in identifying the presence of masked genes in genetic stocks where direct phenotyping failed to detect their presence.

The recessive adult plant leaf rust resistance (APR) gene Lr48 in CSP44 was tagged using simple sequence repeat (SSR) markers. The population was phenotyped under controlled conditions using pathotype 77-5 (121R63-1) at both seedling and adult plant stages. Four microsatellite markers Xwmc175, Xwmc332, Xwmc627 and Xwmc149 were linked to Lr48 and mapped to chromosome 2BL with distances of 10.3, 2.5, 12.6 and 20.7 cM from Lr48 covering a length of 31 cM. Lr48 was placed between markers Xwmc175 and Xwmc332. The earlier reported location of Lr48 on 2BS could not be confirmed. The markers were validated on another population and the closest SSR marker, Xwmc332, was specific to resistance allele Lr48 and did not amplify in wheat lines carrying other resistance genes, thus enabling breeders to pyramid Lr48 with other leaf rust resistance genes.

The leaf rust resistance gene Lr25, transferred from Secale cereale L. into wheat and located on chromosome 4B, imparts resistance to all pathotypes of leaf rust in South-East Asia. In an F(2)-derived F(3) population, created by crossing TcLr25 that carries the gene Lr25 for leaf rust resistance with leaf rust-susceptible parent Agra Local, three microsatellite markers located on the long arm of chromosome 4B were found to be linked to the Lr25 locus. The donor parent TcLr25 is a near-isogenic line derived from the variety Thatcher. The most virulent pathotype of leaf rust in the South-East Asian region, designated 77-5 (121R63-1), was used for challenging the population under artificially controlled conditions. The marker Xgwm251 behaved as a co-dominant marker placed 3.8 cM away from the Lr25 locus on 4BL. Two null allele markers, Xgwm538 and Xgwm6, in the same linkage group were located at a distance of 3.8 cM and 16.2 cM from the Lr25 locus, respectively. The genetic sequence of Xgwm251, Lr25, Xgwm538, and Xgwm6 covered a total length of 20 cM on 4BL. The markers were validated for their specificity to Lr25 resistance in a set of 43 wheat genetic stocks representing 43 other Lr genes.

Syzygium cumini(L.) Skeels (jamun) is a medically important fruit with numerous health protective effects. Seeds of this fruit contain 74.5 % NFE (nitrogen free extracts) and therefore possess a good source of carbohydrates. This fraction consists of high molecular weight carbohydrates (HMWC) like inulin (41.1 %) and resistant starch (3.9 mg/L); and hitherto unquantified low molecular weight carbohydrates (LMWC). This study was performed to extract and quantify LMWC from jamun seeds. To extract LMWC, ethanol concentration, extraction time and solute particle size were evaluated in 21 experimental designs using Response Surface Methodology (RSM) based on the central composite rotatable design (CCRD). A quadratic polynomial equation was obtained by multiple regression analysis. Analysis of variance (ANOVA) tested significance of the factors and their interactions at 95 % confidence interval. High Performance Anion Exchange Chromatography – Pulsed Amperometric Detection (HPAEC-PAD) was used to characterize the prebiotic fraction into individual sugars. Prebiotic potential of LMWC was established by calculating the Prebiotic Activity Score (PAS). A maximum LMWC yield (21 g / 100 g) was obtained when extraction was performed with 50 % ethanol as solvent for 80 to 85 h using the seed powder with 0.6 mm particle size. The predicted yield was in agreement with the experimental value and therefore proved the suitability of the RSM model. This model could be used as a standard for scaling up LMWC extraction from jamun seeds. A positive PAS of 1.532 ± 0.008 ascertained the prebiotic efficacy of the LMWC extracts. This score reflected the ability of probiotics like Lactobacillus acidophilus to gainfully utilize the LMWC in the growth medium in comparison to pathogenic strains like Escherichia coli.