Seventy-seven wild sunflower accessions from USA were compared in France (Mauguio) for 13 quantitative characters using multivariate methods, including clustering, principal component and canonical discriminate analyzes to assess the patterns of morphological and climatic variation. Geographic and climatic data from their sampled sites such as latitude, longitude, elevation, rain fall, temperature, number of rain fall days, temperature range, and sunniness were also analyzed and we sought for correlations of climatic variables and morphological traits. Climatic data clustered the accessions into four groups. Principal component analysis was used to summarize the characteristic habits of annual wild sunflower sampled sites in terms of geography and climates, thus we characterized the ecogeographical profiles of wild sunflowers. As we studied the traits in a common environment we speculated whether local adaptation patterns are sustained by our data. Indeed traits shared by accessions that belong to climatic clusters are suggested to be due to local adaptation.
The resistance of 11 tomato cultivars (Ps-6515, Berlina, Poolad, Petoprid-5, Zaman, Matin, Golsar, Sandokan-F1, Golshan-616, Sadeen-95 and Sadeen-21) to the tomato moth, Tuta absoluta (Meyrick) (Lepidoptera:Gelechiidae) was investigated under field conditions. A randomized complete block design was used with three replications. Data analysis indicated that there were significant differences (P < 0.05) among cultivars regarding leaflet damage, leaf damage, overall plant damage, number of mines per leaf, number of holes on the stem, and fruit. Our findings revealed that the cultivars Berlina, Golsar, Poolad, and Zaman were less suitable cultivars, suggesting that they are more resistant to the tomato moth than the other cultivars. The high density of leaf trichomes present in the cultivars Berlina, Zaman, and Golsar can be one of the possible causes of resistance to T. absoluta. Knowledge of the extent of susceptibility or resistance of cultivars to a pest on a crop is one of the fundamental components of integrated pest management (IPM) programs for any crop.
Plant growth-promoting rhizobacteria possessing ACC deaminase activity reduces the level of stress ethylene, conferring resistance and improving plant growth under different stress conditions. The present study aims at evaluating Pseudomonas fluorescens strains for their potential to produce ACC deaminase and quantifying their effects on seed germination and seedling growth of wheat under salinity stress. Bacteria were first evaluated for their ability to utilize ACC, an immediate precursor of stress ethylene, using DF minimal medium containing 3 mM ACC and it was revealed that they were all able to use ACC as sole nitrogen source under in vitro conditions. Thereafter, the influence of bacterial strains on seed germination and seedling growth of wheat varieties was evaluated under NaCl induced salt stress after seven days. The experimental design was completely randomized in 3×5×5 factorial scheme with three replications. Factors consisted of salinity (0, 3 and 6 dS/m), P. fluorescens bacteria (strains PGU2-79, WBO-3, WKZ1-93 and WB1-7 and sterile water as control), and wheat variety (Chamran, Kooh-Dasht, Dehdasht, Karim and Jam). Twenty wheat seeds were transferred to plates after being soaked for an hour in bacterial suspensions at concentration of 10 8 CFU/ml. Each plate contained a filter paper which was moistened with 10 ml of NaCl solution in different concentrations. Plates were incubated in a growth chamber with maximum and minimum temperatures maintained at 20°C and 15 °C, respectively, with 12 h day-night photoperiod and relative humidity of 80%. Results revealed that P. fluorescens strains had positive impacts on different growth parameters of wheat varieties including germination percentage and rate, seed vigor, length and dry weight of coleoptile and radicle and salinity tolerance index of plants under salinity stress as compared to control. This study reveals the efficacy of plant growth promoting P. fluorescens strains containing ACC deaminase for improving salt tolerance and consequently stimulating the growth of wheat seedlings under salinity stress.
The genetic base of sunflower elite lines is very narrow, due to many years of selection and breeding. To broaden the genetic diversity of the cultivated sunflower, in 1995 73 wild sunflower populations were crossed with 3 cultivated lines (Testers), and 219 hybrid offspring's were evaluated in the field. GCA and SCA effects were computed suggesting for all traits a genetic potential for improvement through selection. Study of the hybrids revealed that the wild accessions bear different genetic abilities to combine with the testers for traits of morphological architecture, phenology and yield (seed weight and seed oil). The variance due to GCA and SCA showed that gene action was additive for days to flowering, branching and plant height. Genotypes derived from the same geographic origin may have either good or poor general combing ability. The correlation between GCA and per se genotype performance was positive for all traits except for seed oil content. This was the first attempt to evaluate wild-cultivated hybrids in sunflower on a large scale and will be the starting point for the management of hybrid Helianthus annuus populations for breeding. GCA and SCA estimations will facilitate the definition of strategies to manage and exploit the natural diversity for this crop.
The aim of this study was to assess the chronic effects of a bio‐pesticide (NeemAzal) on some biochemical parameters of grass carp (Ctenopharyngodon idella) under laboratory conditions. At first, 96 h LC50 of the pesticide was determined using probit analysis software and was found to be 0.73 mg L−1 of the active ingredient (azadirachtin) of the pesticide. Fresh fish were then divided into three treatments and a control and were exposed to sublethal concentrations (10%, 20% and 30% of the 96 h LC50 value) of the pesticide for a month. The biochemical examination of the blood showed a remarkable decrease in values of protein, albumin, AST, ALT, ALP and LDH (P < 0.05).
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