abstract field experiment was conducted to evaluate the effects of sowing date, crop density, and weed interference on yield and yield components of chickpea in lorestan province during 2005-06. the experimental was a randomized complete block design by factorial arrangement with 4 replications. the experiment had 3 factors: sowing date at 2 levels (autumn, and winter), crop density at 3 levels...

development of an autonomous weeding machine requires a vision system capable of detecting and locating the position of the crop. it is important for the vision system to be able to recognize the accurate position of the crop stem to be protected during weeding. several shape features of corn plants and common weed species in the location were extracted by means of morphological operations. eff...

Plants often experience various biotic and abiotic stresses during their life cycle. The abiotic stresses include mainly drought, salt, temperature (low/high), flooding and nutritional deficiency/excess which hamper crop growth and yield to a great extent. In view of a projection 50% of the crop loss is attributable to abiotic stresses. However, abiotic stresses cause a myriad of changes in phy...

An image processing algorithm for detecting individual weeds was developed and evaluated. Weed detection processes included were normalized excessive green conversion, statistical threshold value estimation, adaptive image segmentation, median filter, morphological feature calculation and Artificial Neural Network (ANN). The developed algorithm was validated for its ability to identify and dete...

Engineering of salinity tolerance in agronomically important crop plants is required to increase their productivity by enabling them to grow in saline soils, which are otherwise left uncultivated. Since an increase in the enzymes of glyoxalase system has been shown to impart salinity tolerance in the model plant tobacco, we used the glyoxalase II gene for engineering salinity tolerance in an im...

Since nitrogen (N) is the most essential nutrient for plants and a major limiting factor in plant productivity, doubling agricultural food production worldwide over the past four decades is associated with a 20-fold increase in N fertilizer use. As a consequence, use of N fertilizers in agriculture has already shown a number of detrimental environmental impacts. Therefore, the need to reduce N ...

Gene flow between crop fields and wild populations often results in hybrids with reduced fitness compared to their wild counterparts due to characteristics imparted by the crop genome. But the specifics of the evolutionary outcome of crop-wild gene flow may depend on context, varying due to local environmental conditions and genetic variation within and among wild populations and among crop lin...

In the USA, cultivated sunflower (Helianthus annuus) is often sympatric with wild H. annuus, which is an agricultural weed that grows along roadsides and in other disturbed sites. We found that crop-to-wild gene flow was common (~5-40% hybrids) when wild plants occurred within <1,000 m of the crop, and crop-specific genetic markers persisted in wild populations for many generations. Crop-to-wil...

Plants respond with changes in their pattern of gene expression and protein products when exposed to low temperatures. Thus ability to adapt has an impact on the distribution and survival of the plant, and on crop yields. Many species of tropical or subtropical origin are injured or killed by non-freezing low temperatures, and exhibit various symptoms of chilling injury such as chlorosis, necro...

June 23, 2000 Deciding whether a specific weed infestation is worth treating is usually based on a subjective evaluation of the potential impact of the infestation on crop yields. The two main criteria used are 1) the number of weeds present, and 2) the specific weeds present (foxtail, velvetleaf, etc.). Another factor that is just as important, if not more so, is the emergence date of the weed...