Selection strategies for dairy buffaloes: economic and genetic consequences

Buffaloes are generally raised in Brazil without milk‐recording programs, and thus without genetic evaluations of any of their traits. This study evaluated the economic impacts of three different selection strategies on buffalo populations and the evolution of genetic trends, genetic variances and inbreeding coefficients resulting from each of them. The selection strategies used were as follows: (i) random selection; (ii) phenotypic selection; and (iii) progeny testing (PT). As the numbers of herds enrolled in milk‐recording programs increased, phenotypic selection and PT strategies increased both monetary benefits and genetic trends. The extra costs of implementing milk recording (MR) and PT procedures were exceeded by the income resulting from better buffalo performance. Progeny testing is known to result in beneficial genetic trends and the use of artificial insemination promoted better distributions of genetic material into herds that were not enrolled in milk‐recording programs. Phenotypic selection and PT increased mean milk production ‐ a key factor in profitability. Inbreeding levels remained stable with phenotypic selection, even as the numbers of MR herds increased. Increases in the numbers of sires that were evaluated reduced the mean inbreeding coefficient in PT. Increasing the number of herds enrolled in milk‐recording programs resulted in increased numbers of sires needed for PT, but this did not increase the inbreeding coefficient. In summary, phenotypic selection and PT strategies appear to be economically viable for buffalo husbandry in south‐eastern Brazil under current (2007–2008) economic conditions and should be encouraged.     

Relationship between total nodulation and nodulation at the root crown of peanut, soybean and common bean plants

The objective of this study was to simplify the procedure for evaluation of legume nodulation, by examining if there is a relationship between the nodulation of the whole root system and at the crown region. Roots of peanut, soybean and common bean plants growing in soils were split in two parts (crown and bottom) and assessed for nodulation (nodule number and dry weight). In general, most nodules were concentrated at the crown, and crown nodulation was generally positively correlated with total nodulation of all three legume crops. The results are highly applicable in studies such as strain selection for inoculants and assessment of inoculation technologies, among others, and is an important contribution to help reduce the time and labor required for the evaluation of nodulation parameters.     

Acibenzolar-S-methyl on Meloidogyne javanica control in lettuce

Nematodes are among the main limiting factors of the vegetables productivity, especially due to management restriction this crop to obtain an efficient control of pathogen. Resistance induction using acibenzolar-S-methyl (ASM) has presented promising results in the management of diseases, but to plant-parasitic nematodes the time required to activate latent defense mechanisms is a limiting factor, which can be prevented with the treatment of seedlings in trays. Thus, the present study aimed to assess different times of ASM application to Meloidogyne javanica control in lettuce. Lettuce seedlings were produced in trays, transplanted to pots 25 days after germination and inoculated with 2000 eggs of the nematode. The seedlings were pulverized on shoots with ASM 10 or 5 days before of transplant (DBT), on the day of transplant (DT), 5 or 10 days after transplant (5 or 10 DAT), 10 DBT?+?DT and 10 DBT?+?5 DAT. The untreated plants formed the control group. Fifty days later, these plants were collected and evaluated the nematological and vegetative parameters. The treatments promoted a decrease in M. javanica population higher than 60% when applied until 5 DAT and generally did not interfere with the vegetative parameters of lettuce, and ASM can be adopted as an alternative for the root-knot nematodes management.     

Nitrogen in plant growth and yield of common bean

The aim of this research was to determine the effect of nitrogen (N) availability on wild Rhizobiumnodulation, plant growth and grain yield of the common bean crop. Experiments were conducted in two growing periods, from 2 March to 3 June 2011 (autumn) and from 21 September to 23 December 2011 (spring), in pots using sand as substrate. Nitrogen concentrations of 5.12 (T1), 7.6 (T2), 10.12 (T3), 12.62 (T4), and 15.12 (T5) mmol L^?1 were supplied by fertigation. In spring, the grain yield, number of grains and shoot growth of both cultivars reduced by effect of N concentration but in the cultivar BRS Valente they reducedonly in autumn. Number of nodules and root growth decreased in both cultivars while N concentration increased in the plant tissues. Nitrogen fertilization is not required to the common bean and its use inhibits nodulation. The increased availability does not enhance plant growth and grain yield.     

Use of molecular markers to improve relationship information in the genetic evaluation of beef cattle tick resistance under pedigree‐based models

The selection of genetically superior individuals is conditional upon accurate breeding value predictions which, in turn, are highly depend on how precisely relationship is represented by pedigree. For that purpose, the numerator relationship matrix is essential as a priori information in mixed model equations. The presence of pedigree errors and/or the lack of relationship information affect the genetic gain because it reduces the correlation between the true and estimated breeding values. Thus, this study aimed to evaluate the effects of correcting the pedigree relationships using single‐nucleotide polymorphism (SNP) markers on genetic evaluation accuracies for resistance of beef cattle to ticks. Tick count data from Hereford and Braford cattle breeds were used as phenotype. Genotyping was carried out using a high‐density panel (BovineHD ‐ Illumina^® bead chip with 777 962 SNPs) for sires and the Illumina BovineSNP50 panel (54 609 SNPs) for their progenies. The relationship between the parents and progenies of genotyped animals was evaluated, and mismatches were based on the Mendelian conflicts counts. Variance components and genetic parameters estimates were obtained using a Bayesian approach via Gibbs sampling, and the breeding values were predicted assuming a repeatability model. A total of 460 corrections in relationship definitions were made (Table 1) corresponding to 1018 (9.5%) tick count records. Among these changes, 97.17% (447) were related to the sire's information, and 2.8% (13) were related to the dam's information. We observed 27.2% (236/868) of Mendelian conflicts for sire–progeny genotyped pairs and 14.3% (13/91) for dam–progeny genotyped pairs. We performed 2174 new definitions of half‐siblings according to the correlation coefficient between the coancestry and molecular coancestry matrices. It was observed that higher‐quality genetic relationships did not result in significant differences of variance components estimates; however, they resulted in more accurate breeding values predictions. Using SNPs to assess conflicts between parents and progenies increases certainty in relationships and consequently the accuracy of breeding value predictions of candidate animals for selection. Thus, higher genetic gains are expected when compared to the traditional non‐corrected relationship matrix.     

Meloidogyne luci,a new root‐knot nematode parasitizing potato in Portugal

In 2013, during a field survey conducted in Portugal on potato, Solanum tuberosum, an unusual esterase (EST) phenotype was detected in a root‐knot nematode (RKN) from potato roots collected in Coimbra. This Portuguese isolate was purified and maintained on tomato, S. lycopersicum, and morphological, biochemical and molecular characteristics were studied. Perineal pattern morphology was highly variable, similar to Meloidogyne ethiopica and not useful for identification. The EST phenotype, from young egg‐laying females, displayed three bands similar to the Brazilian M. luci (L3) and distinct from M. ethiopica (E3). Phylogenetic analyses of mitochondrial cytochrome oxidase subunit I and the mitochondrial DNA region between COII and 16S rRNA genes revealed that the Portuguese isolate grouped with M. luci isolates close to M. ethiopica isolates. However, considering the ITS1‐5.8S‐ITS2 region, the Portuguese isolate grouped with isolates of M. luci, M. ethiopica and M. hispanica, which limits the confidence of this region for M. luci diagnosis, and its differentiation from other species with morphological similarities. The M. luci pathogenicity to potato was also assessed in 16 commercial cultivars and compared with M. chitwoodi, considered to be a quarantine RKN species by EPPO. All potato cultivars were susceptible to both Meloidogyne species with gall indices of 5 and higher reproduction factor values ranging from 12.5 to 122.3, which suggests that M. luci may constitute a potential threat to potato production. In the present study, M. luci is reported for the first time attacking potato in Portugal.     

Reconstructing 290 years of a data‐poor fishery through ethnographic and archival research: The East Pacific green turtle (Chelonia mydas) in Baja California,Mexico

Evaluating historical changes in the exploitation of marine organisms is a key challenge in fisheries ecology and marine conservation. In the Eastern Pacific, marine turtles were exploited for millennia before systematic monitoring began <50 years ago. Using ethnographic and historical data, we generated a detailed reconstruction of the East Pacific green sea turtle (Chelonia mydas) fishery in Mexico's Baja California peninsula from 1700 to 1990. Sea turtles from the region's important feeding areas were a staple food source from the earliest phases of human occupation, dating back at least 12,000 years. In contrast with regions such as the Caribbean, small human populations and limited market access resulted in apparently sustainable turtle harvests until the second half of the 20th century. We found that the estimated annual catches between 1960 and 1980 exceeded the estimated annual catches of the previous 250 years by an order of magnitude, leading to the collapse of the fishery and the depletion of the green turtle population. A total ban on sea turtle captures in 1990, comprehensive nesting beach protection, and significant conservation efforts resulted in increases in breeding females on nesting beaches and catch rates in scientific monitoring on main feeding grounds since the early 2000s. This provides a positive outlook for this once‐depleted population segment. Although further research is needed to evaluate current conservation status, we have identified a date, between 1950 and 1960, which can serve as a reliable temporal reference for future evaluations of historical baseline abundance in this region.