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Genetic characterization of maize genotypes is of great importance in maize breeding program to identify diverse populations and divergent genotypes. Divergence and genetic diversity were assessed in a set of 20 maize genotypes representing popcorn, white corn, sweet corn and yellow corn, through morphological characteristics and Random Amplified Polymorphic DNA (RAPD) markers. Field experiment was conducted in randomized complete block design with three replications. Morphological data revealed that sweet corn genotype SCLY-1 was earlier in days to 50% pollen shedding than other genotypes while white corn genotype WL-3 was earlier in days to 50% silking. Maximum plant height was recorded for PCLY-5 (133.3 cm) while lowest for WL-4 (92.8 cm), whereas highest ears height was recorded for popcorn PCLY-1 (64.4 cm) and lowest (29.4 cm) for SCLY-5. The yellow corn had maximum (4.5 kg) grain yield at harvest as compared to sweet and popcorn (3.0 kg). Negative but weak correlation was recorded between ear height and grain yield. Cluster analysis based on yield related parameters grouped all the studied genotypes in to five sub clusters. Molecular genotyping based on four primers amplified 37 loci which were (100%) polymorphic. Maximum elven loci were identified by primer GLA-04, while minimum was reported for primer GLA-03. The loci GLD-18B1000, GLA-04B300 recorded highest gene diversity (0.500) followed by loci GLE-05B750, GLE-05B650 and GLE-05B550. The loci of primer GLD-18 (GLD-18B1000) detected highest alleles evenness and Simpson's diversity index of 1.00 and 0.526, respectively. Maximum gene diversity (0.354) among populations were recorded for yellow corn, while the minimum was detected for white corn (0.254), while genotypic diversity was same for all maize types. Cluster analysis based on molecular genotypic data grouped the maize genotypes into four distinct groups. Lack of concordance was observed while comparing the clustering based on phenotypic and molecular data. The overall diversity among the studied maize genotypes could be used in future maize breeding program. [ABSTRACT FROM AUTHOR]

A greenhouse experiment was carried out at Agricultural Research Station (ARI), Shen Lasht Chitral in 2016-17. A total of 300 samples were collected from the five different locations namely Drosh, Shen Lasht, Garam Chashma, Ayun and Bony Lasht of district Chitral. The soil samples were placed in trays (27 cm × 21 cm × 4 cm = 2268 cm3), and the trays were arranged in three repetitions having 100 samples in each repetition. Each repetition contained samples from 5 locations, in each location 4 sites (east, west, north and south each at 100 m distance from each other) and at each site samples were collected from 5 different depths, making a total of 100 samples in one repetition i.e. 5 × 4 × 5 = 100 and with repetitions making a total of 300 samples in one district. The results identified 31 noxious weeds belong to 17 different plant families in the soil samples of district Chitral.. Out of the 31 different weeds, 23 were broad leaves, 8were grasses and 1was sedge. Moreover, 24 weeds were annuals, while the rest were perennials. A. Among the different locations of Chitral, the highest weed seed bank was recorded in the soil samples of ARS Shen Lasht area.. The lowest seed bank was recorded in the soil samples of Garam Chashma, which was however statistically at par with the rest of the locations studied in Chitral. The major weed seed bank lies in the upper 6-12 cm depth of the soil. Out of the total 31 weeds recorded in soil samples of Chitral, the top 10 weeds in terms of the relative weed densities, relative weed frequencies and importance value indices were Convolvulus arvensis, Rumex crispus, Poa annua, Galium aparine, Avena fatua, Trianthema portulacastrum, Silybum marianum, Sorghum halepense, Euphorbia helioscopia, and Lolium tenulentum species. The Importance Value Indices for these weeds were 14.01, 13.96, 13.07, 11.83, 11.57, 11.12, 10.35, 10.09, 10.02, and 9.99, respectively. Moreover, these IVIs indicate that out of the top most 10 problematic weeds eight weeds are broad leaved and two are grassy weeds. Therefore, for planning of the weed control measures it must be kept that broad leaf weed problems are higher. [ABSTRACT FROM AUTHOR]

Field based assessment of wheat rust resistance was conducted for 29 advanced CIMMYT wheat lines and local checks across three locations of Pakistan vz. Peshawar, Mansehra and Bannu, complemented with molecular marker-based screening. A high disease pressure was prevalent across all locations associated with the favorable cold and wet climatic conditions prevalent during the year (2016). The maximum severity was recorded at Mansehra (up to 90%) followed by Peshawar (up to 50%) and Bannu (up to 45%). Significant variability existed amongst the tested wheat lines for yellow rust severity (ranging from 0% to 90%) and yield potential (ranging from 263 g to 757 g per 4.5 m2 plot). Cluster analysis grouped 29 lines and three checks into four clusters. A better grain yield among the advanced lines was recorded for W-SA-104 (565 g per 4.5 m2 plot), W-SA-115 (452 g) and W-SA-118 (447 g). None of the lines was resistance at every location and thus none had average coefficient of infection “ACI” = 0, though 26 lines were identified to possess partial resistance to yellow rust (with ACI < 20). Genotyping for the presence of resistance genes with molecular markers STS-7 (linked with Yr5), SC-Y15 (linked with Yr17) and Xwmc44 (linked with Yr29) revealed the highest frequency of Yr17 (90.60%) detected in 29 wheat lines, followed by Yr29 (87.5%) detected in 28 wheat lines and then by Yr5 (50%) detected in 16 lines. Among 15 wheat lines (46.87%), three resistant genes were detected together. Variability detected in resistance response based on both field testing and molecular markers could potentially be exploited in wheat breeding to develop better resistance varieties for deployment at field level. [ABSTRACT FROM AUTHOR]

Present study was conducted in the Institute of Biotechnology and Genetic Engineering (IBGE), Faculty of Crop Production, University of Agriculture, Peshawar, Pakistan during 2013 to find out the response of different mutants (cad 2-1 and sir 1-1) of Arabidopsis thaliana impaired in GSH biosynthesis under arsenic (As) stress. Results showed that reduced Glutathione level in cad2-1 and biosynthetic capacity of the sir1-1 mutants made these plants highly sensitive to As applied in the form of sodium arsenate at 100 μM and 200 μM concentrations. Ten days old seedlings of mutants when exposed to sodium arsenate for 14 days were severely affected compared to wild-type plants. This was shown in their growth phenotype, reduced root length, reduced biomass, reduced chlorophyll contents resulting in pale color of the leaves. The seedlings of cad2-1 mutant were found eventually bleached after 12 days when exposed to 200 μM concentration of sodium arsenate whereas the wild-type seedlings were found viable and greenish under the same conditions. Experiments on direct germination showed that seeds of cad2-1 mutant were unable to germinate in the presence of 100 μM and 200 μM concentrations of sodium arsenate unlike wild-type and sir1-1. These results showed that relative anthocyanin contents were accumulated approximately thirteen-fold in the cad2-1 mutant in 200 μM concentration of sodium arsenate which clearly suggest that optimal availability of GSH is critical for the survival of plants under As stress. [ABSTRACT FROM AUTHOR]