Effects of Salt Stress on Vegetative Growth and Ion Accumulation of Two alfalfa (Medicago sativa L.) Cultivars

Salt stress is one of the most chalanging abiotic stresses affecting natural productivity and causing significant croplosses worldwide. A greenhouse experiment was conducted to evaluate the response of two alfalfa cultivars (Bamiand Hamedani) to 6 levels of salinity (0 as control, 25, 50, 75, 100, 125 mM NaCl) at the College of Agriculture,Shiraz University, Shiraz, Iran in 2008. Plant dry weight per pot in both cultivars decreased with increasing salinitylevels. However, Bami as compared to Hamedani, with the lowest Na+ sequestration, produced the greater dry matterweight. Leaf area per pot was significantly affected by salt stress with Bami cultivar showing a higher leaf area thanHamedani. Na+ accumulation also increased by increase in the salinity level in either one of the cultivars; however,Na+ sequestration of Bami as compared to Hamedani, was lower due to Na+ exclusion mechanisms occurring in thiscultivar. Although Cl- accumulation increased with increasing salinity level in either one of the cultivars, Claccumulationwas higher in Hamedani than in the other cultivar. Similar to K+/Na+ ratio, Ca2+/Na+ ratio alsodecreased by an increase in salt stress levels and there were highly significant differences observed between 25 and125 mM of NaCl in either one of the cultivars. There was a strong positive relationship observed between plant drymatter weight and leaf relative water content for both Bami (R2=0.94) and Hamedani (R2=0.96) cultivars under saltstress conditions. All in all, it appears that less adverse effect of salinity on Bami cultivar has made it suitable forgrowth in saline soils as compared to Hamedani in saline areas prevailent in south Iran

Determining the most important features contributing to wheat grain yield using supervised feature selection model

A supervised feature selection algorithm was applied to determine the most important features contributing to wheat grain yield. Four hundreds seventy two fields (as records) from different parts of Iran which were different in 21 characteristics (features) were selected for feature selection analysis. Selection of the wide range of features, including location, genotype, irrigation regime, fertilizers, soil textures, physiological attitudes, and morphological characters, provided the opportunity of precise simultaneous study of a large number of factors in wheat grain yield topic by hand of data mining. The grain yield of each record assumed as target variable. The feature selection algorithm selected 14 features as the most effective features on grain yield. These features included culture type, location, soil texture, 1000 kernel weight, nitrogen supply, irrigation regime, biological yield, organic content of the soil, the amount of rainfall, genotype, plant height, and spike number per unit area. Interestingly, growing season length and plant density were the second most important features for wheat grain yield. Based on the feature selection model, culture type, as dryland farming or irrigated, severely affected wheat grain yield. The soil pH had a marginal effect on wheat grain yield. The results of this investigation demonstrated that feature classification using feature selection algorithms might be a suitable option for determining the important features contributing to wheat grain yield, providing a comprehensive view about these traits. This is the first report in identifying the most important factors on wheat grain yield from many fields using feature selection model.Ehsan Bijanzadeh, Yahya Emam, Esmaeil Ebrahimi

Effect of Different Levels of Sodium Chloride on Germination Characteristics of 20 Cultivars of Bread and Durum Wheat20 Cultivars of Bread and Durum Wheat

Abstract Salt stress is a major stress influencing wheat seedling establishment. A laboratory experiment was conducted to evaluate the response of 20 cultivars of wheat to two levels of salinity (8 and 16 dS/m NaCl), at the College of Agriculture, Shiraz University, Shiraz, Iran in 2008. Maximum root length was obtained in Dabira (5.73 mm) at 16dS/m salinity level. In control, durum wheat cultivars including D81-17, Yavaros, D82-16, D79-15 and Taro3 had the maximum root length compared to bread wheat, however, with increasing salinity level to 16dS/m, minimum root length was observed in D82-16 (0.3 mm). In all cultivars, with increasing salinity level, shoot length was decreased and minimum shoot length was observed in D82-16 and D79-15. Under control conditions, Taro 3 cultivar had maximum seedling dry weight (108.6 mm), however, at 8 and 16 dS/m salinity levels, seedling dry weight of this cultivar was decreased to 92.33 and 78.43 mg, respectively. All seeds (100%) were germinated in D82-16, Taro3, Bolani Cross, and Chamran cultivars under 16 dS/m but in Marvdasht cultivar, seed germination percentage under 8 and 16 dS/m reached to 65 and 50%, respectively. Shiraz (10.8 seeds/day), Adl Cross(10 seeds/day), and Bolani Cross (9.1 seeds/day) had maximum germination rate under 16 dS/m salinity level. Differences among wheat cultivars also found in germination stress index (germination rate under stress divided by germination rate under control) and Shiraz, Adl Cross and Bolani Cross had maximum germination stress index, while Yavaros and D82-16 had minimum germination stress index. Furthermore, with increasing salinity level, different responses were observed among wheat cultivars in root and shoot length, germination rate and germination stress index which demonstrated the genetic diversity among wheat cultivars. It appeared that durum wheat cultivars, compared to bread wheat cultivars, had lower germination stress index and germination rate. Among what cultivars, Bolani Cross, Shiraz and Adl Cross appeared to be more tolerant and Marvdasht, Yavaros and Karkheh more sensitive to salt stress at seedling stage which is worthy of attention by farms growing wheat in saline soils. did not suitable cultivars for salt areas. Keywords: Bread and durum wheat cultivars, Salt tolerance, Germination stress index, Germination rat

Application of unsupervised weighting algorithms for identifying important attributes and factors contributing to grain and biological yields of wheat

To identify important attributes/factors that contribute to grain and biological yields of wheat, 9912 sets of diverse data from field studies were extracted, and supervised attribute-weighting models were employed. Results showed that when biological yield was the output, grain yield, nitrogen applied, rainfall, irrigation regime, and organic content were the most important factors/attributes, highlighted by 9, 7, 5, 3 and 3 weighting models, respectively. In contrast, when grain yield was the output, biological yield, location, and genotype were identified by 8, 6, and 5 weighting models, respectively. Also, five other features (cropping system, organic content, 1000-grain weight, spike number m-2 and soil texture) were selected by three models as the most important factors/attributes. Field water status, such as the irrigation regime or the amount of rainfall, was another important factor related to the biological or grain yield of wheat (weight ≥ 0.5). Our results showed that attribute/factor classification by unsupervised attribute-weighting models can provide a comprehensive view of the important distinguishing attributes/factors that contribute to wheat grain or biological yield. This is the first report on identifying the most important factors/attributes contributing to wheat grain and biological yields-using attribute-weighting algorithms. This study opened a new horizon in wheat production using data mining.E. Bijanzadeh, Y. Emam, E. Ebrahimi, and M. Ebrahim

Growth and Yield Responses of Triticale (X Triticosecale) to Biofertilizer Application Methods and Nitrogen Levels under Weed Competition Conditions

Recently, application of biofertilizers has been introduced as a new strategy in crop nutrition. In order to investigate the effect of application methods of biofertilizer in combination with nitrogen levels on yield and yield components of weed-infested triticale a field experiment was conducted at College of Agriculture and Natural Resources of Darab, Shiraz University in 2013-14 growing season. Experimental design was a split split plot with three replications. The main factor included weedy and weed free plots, subplots included three levels of nitrogen; control, 90 and 180 kg N ha-1 and the sub-sub plots were composed of Azotobacter biofertilizer application methods; seed inoculation, topdressing and without Azotobacter (control). The results showed that the effects of nitrogen and biofertilizers on plant height, number of grains per ear, 1000 grain weight, grain yield and yield components, N content in shoot and grain of triticale were significant. Seed inoculation of biofertilizer showed higher efficiency due to its close relationship with plant root systems. Nitrogen amendment had a positive effect on biofertilizer efficiency, so that application of biofertilizer without use of chemical N, had a lower impact on shoot N content. Application of biofertlizer combined with N fertilizer had a higher impact on shoot N content. Owing to a great competitive ability of this small-grain cereal crop against the weeds, triticale yield was not adversely affected by the weed interference

Decoding naturalistic affective behaviour from spectro-spatial features in multiday human iEEG

The neurological basis of affective behaviours in everyday life is not well understood. We obtained continuous intracranial electroencephalography recordings from the human mesolimbic network in 11 participants with epilepsy and hand-annotated spontaneous behaviours from 116 h of multiday video recordings. In individual participants, binary random forest models decoded affective behaviours from neutral behaviours with up to 93% accuracy. Both positive and negative affective behaviours were associated with increased high-frequency and decreased low-frequency activity across the mesolimbic network. The insula, amygdala, hippocampus and anterior cingulate cortex made stronger contributions to affective behaviours than the orbitofrontal cortex, but the insula and anterior cingulate cortex were most critical for differentiating behaviours with observable affect from those without. In a subset of participants (N = 3), multiclass decoders distinguished amongst the positive, negative and neutral behaviours. These results suggest that spectro-spatial features of brain activity in the mesolimbic network are associated with affective behaviours of everyday life