Cotyledon thermal behavior and pectic solubility as related to cooking quality in common beans

The characteristic of proteins, starch and pectic substances in cotyledons of two bean cultivars varying in cooking time were determined to investigate their possible contribution to bean cooking quality. Both cultivars showed the same enthalpies of starch gelatinization but different protein denaturation enthalpies. The proportion of hot water soluble pectins was higher in Michigan, the cultivar with the lower cooking time, than in Ojo de Cabra, the cultivar with the higher cooking time. These results were not due to differences in pectin methylation or in the ratio of monovalent to divalent cations in the tissue, suggesting that in fresh beans the β-elimination reaction is not the sole or predominant route of thermal pectin degradation. Overall, this study indicates that varietal differences in bean cooking quality may be reflections of the rate of pectin loss during soaking/heating and that the thermal properties of starch and protein fractions seem to have a minor contribution. Researchers involved in this study propose that in fresh beans, the thermal pectin loss results from a two step mechanism: pectin enzymic breakdown during the bean soaking followed by thermal solubilization rather than β-elimination during the bean heating.     

Bacterial diversity and occurrence of ammonia-oxidizing bacteria in the Atacama Desert soil during a “desert bloom” event

The Atacama Desert, located in northern Chile, is one of the driest deserts on the Earth. However, in some years, short and sporadic rainfall in the southern end of this desert has increased the soil moisture that produces ephemeral “desert bloom”. Our goal was to assess the composition of the bacterial community and determine variations in the ammonia-oxidizing bacteria guild diversity from soils collected during the course of the “desert bloom” event. The bacterial composition from this arid soil was determined by cloning and sequencing the 16S rRNA gene. A relatively high diversity of clones belonging to 14 bacterial groups was detected. The ammonia-oxidizers showed a significantly higher diversity of amoA gene clones after the “desert bloom” than during or at the beginning of this event. All sequences obtained were related to Nitrosospira genera and environmental clones. These results suggest that the diversity of ammonia-oxidizing bacteria in this arid soil can be affected by the occurrence of “desert bloom”.     

Red List assessment of nine <Emphasis Type="Italic">Aegilops</Emphasis> species in Armenia

The aims of this study are to determine the geographical and ecological distribution of nine Aegilops species in Republic of Armenia and to make an assessment of their IUCN Red List status, using the IUCN Red list categories and criteria, in order to develop an in situ conservation strategy for wild relatives of wheat in Armenia. Ecogeographic surveys of nine Aegilops species were undertaken over 2 years in Armenia. They included a herbarium survey followed by extensive ground-truthing field surveys where targeted Aegilops species occur. The study showed that of the nine Aegilops species studied, four are threatened and of these, Ae. mutica and Ae. crassa are critically endangered. The latter species may even be extinct in Armenia. Ae. neglecta and A. biuncialis are endangered. Additional studies are required to assess the threat status of Ae. umbellulata. Ae. columnaris was assessed as near threatened, while the remaining species (Ae. triuncialis, Ae. cylindrica and Ae. tauschii) are of least concern. There has been a dramatic decline in the genetic resources of Aegilops species during recent years in Armenia as a result of adverse human impacts such as expansion of agriculture, urbanization and uncontrolled grazing. Several species, especially Ae. mutica and Ae. crassa, should be prioritized in conservation activities in Armenia. Efforts should be made to conserve genetic diversity of crop wild relative species both in situ and ex situ, bearing in mind that their germplasm carries potentially valuable information (traits) that can improve adaptability and productivity of cultivated wheat varieties.     

The archaeology of Ushki Lake,Kamchatka, and the Pleistocene peopling of the Americas

The Ushki Paleolithic sites of Kamchatka, Russia, have long been thought to contain information critical to the peopling of the Americas, especially the origins of Clovis. New radiocarbon dates indicate that human occupation of Ushki began only 13,000 calendar years ago-nearly 4000 years later than previously thought. Although biface industries were widespread across Beringia contemporaneous to the time of Clovis in western North America, these data suggest that late-glacial Siberians did not spread into Beringia until the end of the Pleistocene, perhaps too recently to have been ancestral to proposed pre-Clovis populations in the Americas.     

Timing of precision agriculture technology adoption in US cotton production

The timing of technology adoption is influenced by profitability and farmer ability to bear risk. Innovators are typically more risk tolerant than laggards. Understanding the factors influencing early adoption of precision agriculture (PA) technologies by cotton farmers is important for anticipating technology diffusion over time. The factors influencing the timing of grid soil sampling (GSS), yield monitoring (YMR) and remote sensing (RMS) adoption by cotton producers was evaluated using multivariate censored regression. Data for cotton farmers in 12 states were obtained from a survey conducted in 2009. The factors hypothesized to influence the timing of adoption included farm characteristics, operator characteristics, PA information sources, adoption of other PA technologies, and farm location. The results suggest that different factors influenced when cotton farmers adopted GSS, YMR and RMS after these technologies became commercially available. For example, land ownership was associated with the timing of GSS adoption, but not YMR or RMS adoption; farmer age was correlated with the timing of GSS and YMR adoption, but not RMS adoption; and obtaining PA information from consultants affected the timing of GSS and RMS adoption, but not YMR adoption. The only factors correlated with the early adoption of all three technologies were beliefs that PA would improve environmental quality and the adoption of at least one other PA technology. Thus, the potential for improved environmental quality appears to be a strong adoption motivator across PA technologies, as is the earlier adoption of other PA technologies. This research may be useful for farmers, researchers, Extension personnel, machinery manufacturers, PA information providers and agricultural retailers to anticipate the future adoption of new and emerging PA technologies.     

Screening for resistance to black rot in a Spanish collection of Brassica rapa

Productivity and quality of crops of Brassica rapa L. in north‐western of Spain are highly affected by black rot, caused by the bacterium Xanthomonas campestris pv. campestris (Pammel) Dowson (Xcc). Several races of Xcc have been described in this area, being the race 6 the most frequent in B. rapa crops and races 1 and 4 the most frequent in B. oleracea crops. The control of the disease can be aided by the employment of resistant varieties. The aim of this work was to find sources of resistance to Xcc in a collection of open‐pollinated varieties of B. rapa from north‐western Spain. Resistance was evaluated in 191 landraces. Partial resistance to races 6, 1 and 4 and complete resistance to race 4 were identified in several landraces. Several accessions exhibited partial resistance to the three races. Sources of resistance were identified in landraces of different crops of the species (turnips, turnip greens and turnip tops). These landraces could be grown after selection for resistance or they can be donors of resistance genes in breeding programmes.     

Fe uptake from meso and D,L-racemic Fe(o,o-EDDHA) isomers by strategy I and II plants

One of the most efficient fertilizers to correct Fe deficiency in calcareous soils and waters with high bicarbonate content is based on ferric ethylenediamine-N,N'-bis(o-hydroxyphenylacetic) acid [Fe(o,o-EDDHA)]. Fe(o,o-EDDHA) forms two groups of geometric isomers known as meso and D,L-racemic. To determine the Fe uptake from meso and D,L-racemic Fe(o,o-EDDHA), four iron-efficient plants, two plants representative of strategy I (tomato and pepper) and two plants representative of strategy II (wheat and oats), were grown in hydroponic culture. Results indicated that strategy II plants took up iron from both Fe(o,o-EDDHA) isomers equally. However, strategy I plants took mainly the iron associated with the meso form (the lowest stability isomer).     

Long-term effects of devegetation on composition and activities (including transcription) of fungal communities of a semi-arid soil

A stable plant cover is essential in the semi-arid soils of the Mediterranean area to maintain their fertility and functionality. In a semi-arid area, we have studied abundance, structure, and presence of active species of fungal communities of a devegetated soil (disturbed soil) and vegetated soil (undisturbed soil). Disturbed soil was covered by small spontaneous vegetation (5–10%) compared to undisturbed soils (70%), and this decreased the content of the total organic C, microbial biomass, microbial activity (adenosine triphosphate), and fungal counts. The composition and activities of fungal communities were also investigated by direct extraction of DNA and RNA from soil. Denaturing gradient gel electrophoresis analysis of 18S ribosomal DNA and 18S ribosomal RNA profiles indicated that total and active fungal communities were changed after vegetation removal.     

Bimetallic blends and chitosan nanocomposites: novel antifungal agents against cotton seedling damping-off

Anthracnose disease caused by fungal pathogen Colletotrichum capsici is considered to be one of the most destructive diseases in chilli cultivation as it infects and leads to complete destruction of the crop by infecting the mature fruit in the field and/or during the storage period. The management of the disease is difficult due to the absence of any resistant cultivar and effective fungicide. The current study was initiated to evaluate the antifungal efficacy of the biosurfactant produced by strain Pseudomonas aeruginosa JS29 for biological control of anthracnose disease. The results revealed significant disease reduction using biosurfactant in plant assay which were challenge-inoculated with the fungal spore. In vitro experiments clearly showed that the biosurfactant can effectively inhibit the growth of both spore and mycelia of the pathogen. Moreover, the biosurfactant can also effectively inhibit the fungal growth in detached-fruit assay in different storage conditions. The study confirmed that the biosurfactant has tremendous potential to become a viable, cost-effective and environment-friendly alternative for managing anthracnose disease in field and in post-harvest storage condition.