Spatially Variable Rate Herbicide Application on Durum Wheat in Sicily

Using the conventional farming system, durum wheat requires high rates of herbicide spraying. Herbicide residues can cause pollution of soil and ground water and, therefore, of the entire environment.In order to minimise the environmental impact of herbicides, a home-made system for spatially variable rate crop input application was designed and developed. This system consists of a differential global positioning system (DGPS), a portable computer, specifically developed software and a device for applying rates proportionally related to the machine forward speed.Tests of spatially variable rate herbicide application were carried out in inland Sicily, on a field of 8.4 ha (where a 3-yr crop rotation of broad bean/vetch, durum wheat and durum wheat was practised), using a sprayer modified for applying variable rates and equipped with the above-mentioned system.The results are promising. The spatially variable rate herbicide application allowed an almost even grain yield over the entire field and a saving of 29% of herbicides with respect to the amounts normally used with the conventional farming system.     

Genetic diversity, conservation, and utilization of Theobroma cacao L.: genetic resources in the Dominican Republic

Cacao (Theobroma cacao L.) is a significant agricultural commodity in the Dominican Republic, which ranks 11th in the world for cacao exports. To estimate genetic diversity, determine genetic identity, and identify any labeling errors, 14 SSR markers were employed to fingerprint 955 trees among cacao germplasm accessions and local farmer selections (LFS). Comparisons of homonymous plants across plots revealed a significant misidentification rate estimated to be 40.9 % for germplasm accessions and 17.4 % for LFS. The 14 SSRs amplified a total of 117 alleles with a mean allelic richness of 8.36 alleles per locus and average polymorphism information content (PIC) value of 0.67 for the germplasm collection. Similar levels of variation were detected among the LFS where a total of 113 alleles were amplified with a mean of 8.07 alleles per locus and PIC of 0.57. The observed heterozygosity (H_obs) was 0.67 for the germplasm collection and 0.60 for LFS. Based on population structure analysis 43.9 % of the germplasm accessions and 72.1 % of the LFS are predominantly of the Amelonado ancestry. Among these Amelonado, 51.7 % for the germplasm collection and 50.6 % for LFS corresponded to Trinitario hybrid lineage. Criollo ancestry was found in 7.6 and 9.5 % of the germplasm accessions and LFS, respectively. The Contamana, Nacional, and Iquitos backgrounds were also observed in both populations, but the Curaray background was only detected in the germplasm accessions. No Purús or Guiana ancestry was found in either of the populations. Overall, significant genetic diversity, which could be exploited in the Dominican Republic breeding and selection programs, was identified among the germplasm accessions and LFS.     

Seasonality in rooting of Prosopis chilensis cuttings and in-vitro micropropagation

Seasonality in rooting of cuttings and its relationship with some environmental conditions and growth parameters of Prosopis chilensis (Mol. Stunz) were studied. It was observed that rooting could be induced in cuttings taken from field collections only during the dry season, the period corresponding to the highest vegetative growth and reproductive activity (September to March); however, percentages did not exceed 15%. The rooting response does not occur during the dormant period (May to September). When using cuttings from clonal material growing in the glasshouse, rootings exceeding 80% were obtained in liquid aerated media.

In-vitro micropropagation was assessed in P. chilensis using nodal and apical segments collected both from the field and from clonal material and plantlets grown from seed in the glasshouse. Juvenile material gave an 80% regeneration rate of complete plants in Murashige-Skoog medium fortified with 5 mg naphtaleneacetic acid 1⁻¹ and 10 mg cysteine 1⁻¹. In this same medium, the regenerative response of segments obtained from rooted cuttings was 60%. The material collected from the field showed no rooting responses.     

Wound management in reptiles.

Our understanding into the healing response of reptile wounds is in its infancy. To date, many of the methods we have used have been adopted from human, mammalian, or avian species, with varying success. Future research should focus on the development of methods to improve our management of contaminated wounds, minimize the negative inflammatory responses occurring in a wound, and shorten wound-healing time.     

Molecular identification and distribution of mangrove oysters ( Crassostrea) in an estuarine ecosystem in Southeast Brazil: implications for aquaculture and fisheries management

This study investigated the existing species of Crassostrea in the natural environment, farming systems and artificial spat collectors at a protected estuarine area in Brazil, through PCR‐RFLP of mitochondrial 16S rRNA. Among 450 samples collected in the natural environment, 303 were C. brasiliana and 147 C. rhizophorae. Oysters present in the rocky subtidal zone were C. brasiliana. However, both species occurred on mangrove roots in the intertidal zone. Farm‐raised samples included only C. brasiliana. It was observed that attached specimens in commercial collectors had a banding pattern distinct from C. brasiliana and C. rhizophorae, indicating the presence of a third species in the estuary. The 16S rRNA sequence analysis showed that these specimens are clustered with the oysters from Pacific and Indian Oceans, and genetically close to the oysters of Beihai, China (0.3% genetic distance). Oysters obtained from the seed capture showed 17.8% distance of in relation to C. brasiliana, 17.6% for C. rhizophorae and 10.3% for C. gigas, demonstrating high genetic divergence from these species. The occurrence of an exotic species in the Cananéia estuary may have strong ecological and economic implications which require new guidelines for farming, conservation and sustainable fisheries management for the native oyster species.     

Fumigant bioactivity of five Citrus essential oils against Tribolium confusum

During the past decades, the huge use of pesticides caused several environmental problems, so research investigations moved to find a series of compounds with selective toxicity, of a biodegradable and environment-friendly nature, maintaining a positive action in crop and stored products protection. In this perspective, interesting results in the control of pests and fungal pathogens were obtained using essential oils, which are compounds produced by many species of plants as secondary metabolites. The purpose of this research was to evaluate the fumigant activity of five Citrus essential oils against the confused flour beetle Tribolium confusum Du Val, planning a possible employment in the mill industry. The fumigant effectiveness was evaluated 24, 48, 72 hours and 7 days after the start of exposure and each essential oil was analyzed by means of GC and GC/MS. Further evaluations about the toxicity of these compounds were made by partially filling the glass vials with food matrix, in order to assess the possible interference of this matter on the active compounds. The data obtained indicated that, at a low level of fumigant concentration, essential oils can effectively control stored product pests; in the presence of debris, like flour, the efficacy decreased. Plant extracts caused also increased mortality levels after the end of fumigation. The results obtained from this experimentation confirm the efficacy of essential oils in pest control and, in particular, against stored product pests.     

Wild-weed-crop complexes of common bean (Phaseolus vulgaris L., Fabaceae) in the Andes of Peru and Colombia, and their implications for conservation and breeding

During germplasm explorations carried out in Peru and Colombia, interbreeding complexes of wild and cultivated common bean were observed in both countries, eight in Apurimac and Cusco departments of Peru and eight in Cundinamarca and Boyaca´ departments of Colombia. The existence of complexes was evidenced both by segregation of wild and cultivated morphological traits in certain populations, and by the presence of genetically stabilized weedy types which were assumed to have arisen from past hybridization. Observations on phaseolin seed protein confirmed that genetic exchange was occurring. Phaseolin types introduced from other regions were in incipient stages of introgression into local populations. On the other hand, local phaseolin types were observed in all phases of the complexes from totally wild to fully cultivated beans, suggesting that the complexes had undergone a long evolution. Complexes could be an effective means to generate genetic variability, introgressing genes from wild populations into cultivated types and complementing modern plant breeding programs. The conservation of such complexes depends on the continued existence of the wild, weedy and cultivated beans in close proximity; on the maintenance of a semi-domesticated environment; and on the willingness of farmers to leave weedy types in the field.