Polycyclic Aromatic Hydrocarbon Deposition in the Snowpack of the Athabasca Oil Sands Region of Alberta,Canada

In the Athabasca Oil Sands Region (AOSR) of Alberta, Canada, increased concentrations of polycyclic aromatic hydrocarbons (PAHs) in the regional ecosystems and downstream of oil sands development have been observed, presumably originating from various sources including those of oil sands and non-oil sands activities. In this study, we investigated the extent that oil sands activities contribute PAHs to the snowpack of the AOSR. The dominant groups of PAHs found in our snow samples were dibenzothiophenes, phenanthrenes/anthracenes, fluranthenes/pyrenes, chrysenes, and fluorenes. These PAHs were highly dominated by alkylated species, especially near oil sands operations. Aerial deposition of PAHs declined exponentially with increasing distance from the geographic center (GC), which was located close to Suncor and Syncrude’s oil sands operations. The higher aerial deposition at similar distances from GC in the N-S versus W-E directions reflects that PAH inputs from oil sands operations are clustered along the Athabasca River. Patterns of air parcel movements, derived from HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) modeling, closely matched patterns of aerial deposition, supporting that regional wind patterns influence the transport of PAHs emitted by oil sands operations in the AOSR. The source attribution techniques employed in this study revealed that sampling location influenced the characteristics of PAHs deposited. PAHs deposited at sites close to GC were associated with industrial activity, whereas the influences of other sources became increasingly apparent as distance increased from major oil sands areas.     

Characterization of <Emphasis Type="Italic">Prosopis cineraria</Emphasis> (L.) Druce germplasm with suitable horticultural traits from the hot arid region of Rajasthan,India

Sixteen germplasm accessions of Prosopis cineraria with suitable horticultural traits were identified from north-western Rajasthan, India, propagated clonally by budding on seedling rootstock and maintained in the field gene bank. Morphological characterization of seven-year-old trees of these accessions by 21 traits indicated a lot of variation among the accessions tested. Higher number of flowers per raceme was found in accession CIAH/K2, higher width of ripened pod in CIAH/K5, higher number of seeds per pod in CIAH/K12 and a higher weight of seed per pod in CIAH/K6. Overall, CIAH/K16 was found to be a superior genotype for most of the useful traits. High significant positive correlation was obtained with traits useful for horticultural values. Out of 62 random decamer primers for random amplification (RAPD) reaction, and four minisatellite core sequence for direct amplification of minisatellite DNA (DAMD) screened with these accessions, 12 RAPD and 2 DAMD primers were found polymorphic. Average polymorphism resolved by these markers among the accessions was 93.2%. Genetic diversity revealed by Jaccard’s co-efficient was between 0.11 and 0.77, and four major clusters were identified among these accessions by phylogenetic analysis using NTSYSpc-2.02e software. This study shows the existence of high genetic diversity within these accessions.     

Marker‐assisted backcross breeding to combine multiple rust resistance in wheat

A widely grown but rust susceptible Indian wheat variety HD2932 was improved for multiple rust resistance by marker‐assisted transfer of genes Lr19, Sr26 and Yr10. Foreground and background selection processes were practised to transfer targeted genes with the recovery of the genome of HD2932. The near‐isogenic lines (NILs) of HD2932 carrying Lr19, Sr26 and Yr10 were individually produced from two backcrosses with recurrent parent HD2932. Marker‐assisted background selection of NILs with 94.38–98.46% of the HD2932 genome facilitated rapid recovery of NILs carrying Lr19, Sr26 and Yr10. In the BC₂F₂ generation, NILs were intercrossed and two gene combinations of Lr19+Yr10, Sr26 + Yr10 and Lr19+Sr26 were produced. A total of 16 progeny of two gene combinations of homozygous NILs of HD2932 have been produced, which are under seed increase for facilitating the replacement of the susceptible HD2932 with three of the sixteen improved backcross lines with resistance to multiple rusts.     

Discovery of a new gene causing dark green cotyledons and pathway of pigment synthesis in lentil (Lens culinaris Medik)

A new gene is reported which functions as a master gene for synthesis of the pigments determining cotyledon colour in lentil. This gene is different from the two earlier reported genes which are responsible for synthesis of yellow (gene Y) and brown (gene B) pigments. Double recessive homozygous condition of these two genes results into loss of both pigments and, consequently, produces light green cotyledons. The new gene, in contrast, produces dark green cotyledons in recessive condition irrespective of the dominance or recessive state of the Y and B genes. It is hypothesized that the new gene for dark green cotyledon colour (Dg) acts at an earlier stage in the biosynthesis of the two cotyledon-specific pigments, which are derived from a common precursor, whose synthesis is blocked when Dg mutates to its recessive condition. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effect of cytoplasmic male-sterility in sorghum on host plant interaction with sorghum midge,Contarinia sorghicola

Summary Sorghum midge, Contarinia sorghicola Coq. (Diptera: Cecidomyiidae) is one of the most important pests of grain sorghum worldwide. We studied the reaction of midge-resistant and midge-susceptible genic-cytoplasmic male-sterile (A-lines) and their maintainers (B-lines), and the effect of resistant and susceptible restorers on sorghum midge. Midge damage and adult emergence were significantly lower on the B-lines of midge-resistant genotypes (PM 7061 and PM 7068) than their corresponding A-lines, while the reverse was true for the midge-susceptible genotypes (296A and ICSA 42). Differences in midge damage and the number of midges emerged were not significant between the midge-resistant and midge-susceptible A-lines when infested without pollination (except midge emergence on PM 7061A). Pollination with a midge-resistant restorer (DJ6541) reduced midge emergence significantly in one of two seasons. Source of pollen did not influence midge emergence on the highly-resistant A-line, PM 7061A. The implications of these observations in the development of midge-resistant hybrids were discussed.     

Variation in inheritance of resistance to sorghum midge, Stenodiplosis sorghicola across locations in India and Kenya

Sorghum midge [Stenodiplosis sorghicola (Coquillett)] is an important pest of grain sorghum, and host plant resistance is one of the important components for the management of this pest. We studied the inheritance of resistance to this insect involving a diverse array of midge-resistant and midge-susceptible genotypes in India and Kenya. Testers IS 15107, TAM 2566, and DJ 6514, which were highly resistant to sorghum midge in India, showed a greater susceptibility to this insect in Kenya. The maintainer lines ICSB 88019 and ICSB 88020 were highly resistant to sorghum midge in India, but showed a susceptible reaction in Kenya; while ICSB 42 was susceptible at both the locations. General combining ability (GCA) effects for susceptibility to sorghum midge for ICSA 88019 and ICSA 88020 were significant and negative in India, but such effects were non-significant in Kenya. The GCA effects of ICSB 42 for susceptibility to sorghum midge were significant and positive at both the locations. The GCA effects were significant and positive for Swarna, and such effects for IS 15107 and TAM 2566 were negative at both the locations. GCA effect of DJ 6514 were significant and negative in India, but non-significant and positive in Kenya; while those of AF 28 were significant and positive during the 1994 season in India, but significant and negative in Kenya. Inheritance of resistance to sorghum midge is largely governed by additive type of gene action. Testers showing resistance to sorghum midge in India and/or Kenya did not combine with ICSA 88019 and ICSA 88020 to produce midge-resistant hybrids in Kenya. Therefore, it is essential to transfer location specific resistance into both parents to produce midge-resistant hybrids.     

Alteration in important quality traits and antioxidant activities in Brassica oleracea with Ogura cybrid cytoplasm

In vegetable brassicas, cytoplasmic male sterility (CMS) system is the most preferred mechanism for hybrid seed production and Ogura cybrid cytoplasm is the only source used widely. Effects of the alien cybrid cytoplasm on important quality traits need to be understood for their effective use in breeding programme. In analysing 38 Ogura cybrid cytoplasm‐based cauliflower CMS lines, it was revealed that introgression of Ogura cytoplasm resulted in significant alteration in important quality traits. Cupric reducing antioxidant activity and ferric reducing ability of plasma values were increased up to 5–10 times in different genotypes. Among 38 analysed CMS lines, concentration of plant pigments such as anthocyanin, total chlorophylls and ascorbic acid was reduced in 21, 17 and 32 genotypes, respectively. However, the concentration of total carotenoids and β‐carotene was elevated in most of the CMS lines and total carotenoid was increased up to 20 times in the CMS line, Ogu13‐85‐2A. The results indicate the role of nuclear–cytoplasmic interaction and mitochondrial genome in determining concentration of different quality traits.     

Inheritance and molecular mapping of restorer‐of‐fertility (Rf) gene in A2 hybrid system in pigeonpea (Cajanus cajan)

Inheritance of fertility restorer gene in pigeonpea was studied using F₂ and BC₁F₁ populations derived from cross AL103A × IC245273. It was found to be controlled by single dominant gene. Out of 228 SSR primer pairs, 33 primer pairs showed parental polymorphism, while four primers were found polymorphic in bulk segregant analysis (BSA). These four primers viz., CcM 1615, CcM 0710, CcM 0765 and CcM 1522 were used for genotyping of F₂ population and were found to be placed at 3.1, 5.1, 28.1 and 45.8 cM, respectively. Two of them, CcM 1615 and CcM 0710, evinced clear and unambiguous bands for fertility restoration in F₂ population. The Rf gene was mapped on linkage group 6 between the SSR markers CcM 1615 and CcM 0710 with the distances of 3.1 and 5.1 cM, respectively. The accuracy of the CcM 1615 was validated in 18 restorers and six maintainer lines. The marker CcM 1615 amplified in majority of male restorer lines with a selection accuracy of 91.66%.     

Identifying high yielding stable winter wheat genotypes for irrigated environments in Central and West Asia

Improved winter wheat (Triticum aestivum L.) cultivars are needed for the diverse environments in Central and West Asia to improve rural livelihoods. This study was conducted to determine the performance of elite winter wheat breeding lines developed by the International Winter Wheat Improvement Program (IWWIP), to analyze their stability across diverse environments, and to identify superior genotypes that could be valuable for winter wheat improvement or varietal release. One hundred and one advanced winter wheat breeding lines and four check cultivars were tested over a 5-year period (2004–2008). Grain yield and agronomic traits were analyzed. Stability and genotypic superiority for grain yield were determined using genotype and genotype × environment (GGE) biplot analysis. The experimental genotypes showed high levels of grain yield in each year, with mean values ranging from 3.9 to 6.7 t ha⁻¹. A set of 25 experimental genotypes was identified. These were either equal or superior to the best check based on their high mean yield and stability across environments as assessed by the GGE biplot analysis. The more stable high yielding genotypes were ID800994.W/Falke, Agri/Nac//Attila, ID800994W/Vee//F900K/3/Pony/Opata, AU//YT542/N10B/3/II8260/4/JI/Hys/5/Yunnat Esskiy/6/KS82W409/Spn and F130-L-1-12/MV12. The superior genotypes also had acceptable maturity, plant height and 1,000-kernel weight. Among the superior lines, Agri/Nac//Attila and Shark/F4105W2.1 have already been proposed for release in Kyrgyzstan and Georgia, respectively. The findings provide information on wide adaptation of the internationally important winter wheat genotypes, and demonstrate that the IWWIP program is enriching the germplasm base in the region with superior winter wheat genotypes to the benefit of national and international winter wheat improvement programs.