Iran Agricultural Research
Volume:33 Issue: 1, Summer and Autumn 2014

Manual harvesting of saffron as a laborious and exhausting job; it not only raises production costs, but also reduces the quality due to contaminations. Saffron quality could be enhanced if automated harvesting is substituted. As the main step towards designing a saffron harvester robot, an appropriate algorithm was developed in this study based on image processing techniques to recognize and locate saffron flowers in the field. Color features of the images in HSI and YCrCb color spaces were used to detect the flowers. High pass filters were used to eliminate noise from the segmented images. Partial occlusion of flowers was modified using erosion and dilation operations. Separated flowers were then labeled. The proposed flower harvester was to pick flowers using a vacuum snapper. Therefore, the center of the flower area was calculated by the algorithm as the location of the plant to be detected by the harvesting machine. Correct flower detection of the algorithm was measured using natural images comprising saffron, green leaves, weeds and background soil. The recognition algorithm’s accuracy to locate saffron flowers was 96.4% and 98.7% when HSI and YCrCb color spaces were used. Final decision making subroutines utilize artificial neural networks (ANNs) to increase the recognition accuracy. A correct detection rate of 100% was achieved when the ANN approach was employed.

Iran achieved its self-sufficiency goal in wheat production a few years ago, perhaps at the expense of decreasing the production of other grains specially barley as stated by critics in the country. Considering the dependency of wheat and barley markets on each other, policy preference functions were estimated separately for each market. Incorporating political weights, a game theory approach was utilized to investigate welfare impacts of such attempt. Results not only justified the critic's claims, but also indicated that welfare had been transmitted from wheat producers to consumers and the government. Also despite the positive welfare surplus of producers and consumers in the wheat market, high government expenses have led to welfare losses, while barley is associated with welfare gains. Finally, an overall Nash equilibrium occurs as the best strategy between the two markets with a 15% increase in the consumer price of wheat and a 20% decrease in barley production costs. These results undoubtedly imply that optimal social welfare is associated with mitigating the government's role in the wheat market.

Desert truffles are hypogeous ascomyceteous ectomycorrhizal fungi, occurring in arid and semi-arid ecosystems. A PCR-based method was developed for the identification of 3 major desert truffles of Iran: Terfezia claveryi, Tirmania pinoyi and Tirmania nivea based on internal transcribed spacers of rDNA. Two specific PCR primers were designed for T. claveryi, 4 for T. pinoyi, and 2 for T. nivea. All primers were specific to their homologous species and neither set amplified purified DNA from other truffle species or soil-borne micromycetes. In conventional PCR, the limits of detection were 10-500 pg DNA. ITS-Tfc1 primers detected the species in host tissues using a nested-PCR method by ITS1 and ITS4 universal primers as external set.

Lactic acid bacteria are commonly found in the gastrointestinal tract of various endothermic animals and humans, in milk, dairy and seafood products and on some plant surfaces. The aim of this study was to investigate the inhibitory effect of isolated lactic acid bacteria from intestines of narrow-barred Spanish mackerel (Scomberomorus commerson) on Listeria innocua growth. Five strains of lactic acid bacteria (LAB) were isolated. Lactobacillus buchneri, Lactococcus lactis, Lactobacillus acidophilus, Lactobacillus fermentum and Sterptococcus salivarius strains were presumptively identified by biochemical and physiological tests. Anti-listerial activities of these isolates and their cell free supernatants (CFS) were evaluated using agar spot tests, agar well diffusion assays and BHI broth. The results revealed that all cultures and their cell free supernatants were able to inhibit L. innocua growth. Furthermore, the study showed that wastes of this kind of warm water sea fish, have antagonistic activities against L. innocua and can be potentially used as a free source of LAB.

The evaluation of leaf area and leaf nutritional value is important for crop growth modeling and estimations of its performance. The purpose of this study was to use image processing techniques to develop an economical method to ease the assessment of nutrient status and leaf area (LA) of plants and to compare the outcomes of this method with linear models. Leaf area and leaf chlorophyll (LChl) estimation models were developed for apples (Red delicious and Golden delicious) using a leaf area meter and a chlorophyll meter (SPAD 502), respectively. Linear models were developed by measuring the length (L) and width (W) of the leaves. Two models (LA= 1.01 + 0.82LW and LA= 1.23 + 0.87LW) were found to provide the most accurate estimations (R 2 = 0.94, MSE = 4.6 and R 2 = 0.94, MSE = 4.7) of leaf area for Red Delicious and Golden Delicious apples, respectively. Results also showed that the image processing technique was able to estimate leaf area with good accuracy (R 2 = 0.98, MSE = 4.6). The calculation of leaf area in this technique is easier and more accurate than linear models. The best model for leaf chlorophyll estimation using the image processing technique was (LChl= - 0.55 red - 0.45green +0.32 blue + 92) which was highly accurate (R 2 = 0.95, MSE = 7.4).

This experiment was carried out during the growing seasons of 2010 and 2011 at the Agricultural Research Farm of Bu-Ali Sina University, to study the effect of weed competition on subsequent germination and seed vigour of chickpea. 12 weed interference durations were evaluated in a randomized complete block design with three replications. Experiments consisted of two sets of treatments. In the first set, the crop was kept weed-free until 0, 14, 28, 42, 56 and 70 days after sowing and in the second set, weeds were permitted to grow within the crop until 0, 14, 28, 42, 56 and 70 days after sowing. Results of the two year experiments showed that the traits germination index, germination rate, mean germination time, percentage of germination, abnormal seedling percentage and seedling dry weight were affected by different duration of weed interference. Thereafter, the maximum value of germination rate and the minimum value of mean germination time belonged to the full weed-free condition. The increasing length of weed competition decreased seedling dry weight and increased abnormal seedling percentage. This finding is supported by a reduction in the seed weight. In other words, a decrease in seed storage contents resulted in a decrease in seedling growth and an increase in the percentage of abnormal seedlings.

Noise is considered as one of the most debilitating conditions in farming operations. In this study, a number of factors affecting the noise generated by Sampo 3065 combine harvesters were evaluated. Factors were engine speed and gear ratio for combines with and without original cabins. A factorial experiment arranged as a completely randomized design with four replicates was used. Results indicated that loudness level correlated strongly with A-weighted sound pressure level (R2=0.99) but had a weak relationship with linear sound pressure level (R2 = 0.60). Other results showed that original cabins decreased 30.5, 22.8 and 5.4 percent of the loudness level, A-weighted and linear sound pressure levels, respectively. Mean value averages for loudness level, A-weighted and linear sound pressure levels for high engine speed were 6.9, 9.1 and 11.1 percent higher than those at low engine speed.