Genetic Improvement Programs Research Articles

Effect of different cytokinin sources on in vitro/ex vitro multiplication and rooting rate in Eucalyptus spp.

Eucalyptus globulus Labill. is of great interest to the pulp industry. However, the species is highly susceptible to leaf spot caused by Teratosphaeria nubilosa and has a low rooting capacity. In order to overcome these limitations, INIA has been implementing a genetic improvement program for this species and the generation of interspecific hybrids. The strategy is based on the selection of E. globulus clones with high precocity or foliage turnover, since the adult foliage is more tolerant to T. nubilosa. In addition, controlled crosses of E. globulus and E. maidenii with E. grandis are carried out to incorporate disease resistance and ease of rooting. The multiplication of the selected materials is carried out by micropropagation, but the low rooting capacity is a trait that needs improvement. The cytokines necessary for in vitro proliferation can have a negative effect on the rooting process. Benzyladenine is the most commonly used cytokine because of its low cost and easy availability, with some negative effects on rooting, while meta-topolin is a cytokine of lesser impact. The objective of this study was to evaluate the effect of benzyladenine and meta-topolin on the multiplication rate, rooting percentage and plantlets survival of E. globulus, E. grandis × E. globulus, and E. grandis × E. maidenii. In multiplication media, benzyladenine was supplied at 0.4 µM, while two concentrations of meta-topolin (0.4 and 2 µM) were used. Preliminary results indicated a higher multiplication rate with the inclusion of meta-topolin in both concentrations. The in vitro rooting percentage of explants treated with meta-topolin was 51% and 44%, at 0.4 and 2 µM, respectively, while with benzyladenine was lesser (37%). After 28 days post-transplanting, survival was higher in meta-topolin-derived plants. Meta-topolin improved multiplication, in vitro rooting and acclimation of plants. The use of this hormone could improve micropropagation protocols, facilitating rooting and multiplication of valuable genotypes.

RAIZ’s eucalypt genetic improvement program: The path taken and new challenges

RAIZ is a forest and paper research institute, part of The Navigator Company, a Portuguese pulp and paper company. Its eucalypt genetic improvement program started in the mid-1980s, focused mainly on E. globulus, which is well suited to the local soil and climate conditions and has outstanding wood qualities for pulp and paper production. Initially, main selection criteria were growth, survival to drought conditions, wood density and pulp yield. Cloning was the main form to transfer results into operational plantations and, as a result, rooting ability was also a key trait for successful large-scale nursery plant production. These requirements were maintained for several decades during which the program has achieved substantial gains and the E. globulus clonal forest was a reality. Meanwhile, interspecific hybridization has been tested mainly to achieve higher drought and pest resistance. As a result, the clonal program includes several hybrids. Currently, 11 clones, including three hybrids, are in nursery large-scale production, with operational gains of 30-50% over unimproved stocks, in terms of pulp produced per hectare. In the last decade, more than 250 controlled-crosses were carried out, including 70 interspecific crosses. More than 400 new clones, including 50 hybrids, and approximately 400 seed lots, including 100 hybrids and other species lots, have been tested across over 140 sites. Advanced BLUP analysis techniques are used since mid-1990’s to support strategic planning decisions, including more than 125,000 records for survival, 85,000 records for height and diameter, 57,000 pilodyn and 6,000 NIR records, collected from 219 trials, and covering about 45,000 individual genotypes. Nevertheless, efforts to face climate changes must be intensified, especially to mitigate the effects of drought and pests that currently affect a substantial portion of the forest estate. In the last 3 years, more than 100 new genotypes were selected from hybrids progeny trials involving species such as E. grandis, E. viminalis, E. saligna, E. rudis, E. urophylla, and E. tereticornis. Their multiplication and testing are undergoing, and results are expected within 5 years. In addition, an expanded approach to further diversify and strengthen of eucalypt genetic pool is being implemented, introducing species like E. cladocalyx, E. gomphocephala, E. benthamii, E. melliodora, E. punctata, or E. dunnii, aiming to enhance resilience to environmental challenges and ensuring the sustainability of Portugal's eucalyptus forests.

Polyembryonic twin seedlings in Madhuca diplostemon (Sapotaceae) - a critically endangered and endemic species of the Western Ghats

Madhuca diplostemon is a critically endangered and endemic species of the southern Western Ghats, represented by a single mature individual. The occurrence of twin seedlings in this species is being reported here for the first time will be useful future genetic improvement and conservation programs for this species.

Macro- and Micronutrient Contents and Their Relationship with Growth in Six Eucalyptus Species

Knowing nutrient allocation dynamics in the tissues and the characteristics related to growth in different forest species is crucial to fertilization management and selecting better species for specific environments, ensuring greater fertilization efficiency and consequent sustainability in the forestry sector through the rational use of fertilizers. The objectives of this study were (i) to evaluate the content of macro- and micronutrients in different tissues of eucalyptus species and (ii) to relate them with their growth. The treatments were composed of six eucalyptus species (Eucalyptus camaldulensis Dehnh., Corymbia citriodora Hook., E. saligna Sm., E. grandis W. Hill ex Maiden, E. urograndis, and E. urophylla S. T. Blake). Macro- (nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur) and micronutrient (boron, copper, iron, manganese, and zinc) contents were determined in the leaves, bark, and sapwood. To study the functional patterns in macro- and micronutrient contents, Canonical Variable Analysis (CVA) was performed. The first two canonical variables in nutrient content of leaves, bark, and sapwood and the growth variables of eucalyptus species accumulated values greater than 80% of variance. The species E. grandis and E. urograndis showed the highest means for volume and total height but showed no differences regarding the concentration of major elements in the tissues, except the iron content in the bark, which was higher compared to other species. CVA proved to be an excellent tool for understanding, identifying, and classifying the strategies of Eucalyptus sp. regarding the content of nutrients in the shoot biomass tissues and may support genetic improvement programs aiming at identifying potential species. Future research involving the use of remotely piloted aircraft and remote sensors could be a strategy to monitor nutrient contents in different parts of trees throughout the cycle of different eucalyptus species.

Genetics Studies on the Agromorphological Parameters of Some Ecotypes of Okra

The nutrient-rich okra, Abelmoschus esculentus, plays an essential role in the nutritional balance of rural populations in Chad, whose diet is based on cereals. Okra is also of considerable economic importance to women. However, Doba growers use traditional varieties which do not meet their acceptance criteria, making it essential to create new cultivars. For this reason, it was necessary to identify local population varieties with important characteristics. To this end, 9 ecotypes with varied agromorphological characteristics were sown in the field using a Fisher block design with 3 replications. Analysis of variance showed that there was considerable variability between the ecotypes used for all the agromorphological parameters studied (p<0.05). The results of the principal component analysis showed that ecotypes 2 and 4, the number of leaves per plant and the number of fruits per plant were positively and significantly correlated with the F1 axis (34.49%). Ecotype 6 and the number of seeds per fruit were strongly correlated with the F2 axis (27.90%). The correlation coefficient showed that number of seeds per fruit and plant height (r = 0.61); number of fruits per plant and number of leaves per plant (r = 0.77); number of fruits per plant and fruit width (r = 0.57); can be improved simultaneously. The integration of these agromorphological characteristics into the genetic improvement program could combat food insecurity and promote financial autonomy for women in Doba.

Taxonomic, physicochemical, phenolic and antioxidant comparison in species of high Andean wild fruits: Rubus and Hesperomeles

Currently, humans are taking better care of their health. It is known that fruit consumption prevents degenerative diseases such as cancer and diabetes. On the other hand, the high Andean biodiversity is rich in various resources that have been undervalued up to now. In the present study, the botanical characterization, physical and chemical properties, phenolic compounds, and antioxidant capacity were compared in four non-climacteric high Andean wild fruits of the species Rubus (black siraca and red siraca) and Hesperomeles (pacra and capachu), collected in the Peru province of Andahuaylas, Apurimac region, between 3600 and 3900 m.a.s.l. The taxonomic identification was performed according to the catalog of angiosperms and gymnosperms by geographical location. Polyphenols were determined by the spectrophotometric method based on the use of the Folin–Ciocalteu reagent, and the antioxidant capacity by the DPPH reagent discoloration method. Data in triplicate were analyzed by a one-way analysis of variance (ANOVA) and a multiple-range test of least significant difference (LSD). The results showed significant differences (p < 0.05) in all properties studied. The maturity index and phenolic content directly affected the antioxidant capacity. The four wild fruits studied presented high values of polyphenols and antioxidant activity. Therefore, they should be considered in genetic improvement and field extension programs to promote their consumption, which would encourage healthy and nutritious eating.

Unraveling the occasional occurrence of berry astringency in table grape cv. Scarlet Royal: a physiological and transcriptomic analysis.

Scarlet Royal, a mid-season ripening table grape, is one of the popular red grape varieties in California. However, its berries develop an undesirable astringent taste under certain conditions. Among the various factors contributing to the degradation of berry attributes, the levels and compositions of polyphenols play a fundamental role in defining berry quality and sensory characteristics. To comprehend the underlying mechanism of astringency development, Scarlet Royal berries with non-astringent attributes at the V7 vineyard were compared to astringent ones at the V9 vineyard. Biochemical analysis revealed that the divergence in berry astringency stemmed from alterations in its polyphenol composition, particularly tannins, during the late ripening stage at the V9 vineyard. Furthermore, transcriptomic profiling of berries positively associated nineteen flavonoid/proanthocyanidins (PAs) structural genes with the accumulation of PAs in V9 berries. The identification of these genes holds significance for table grape genetic improvement programs. At a practical level, the correlation between the taste panel and tannin content revealed a threshold level of tannins causing an astringent taste at approximately 400 mg/L. Additionally, berry astringency at the V9 vineyard was linked to a lower number of clusters and yield during the two study seasons, 2016 and 2017. Furthermore, petiole nutrient analysis at bloom showed differences in nutrient levels between the two vineyards, including higher levels of nitrogen and potassium in V9 vines compared to V7. It's worth noting that V9 berries at harvest displayed a lower level of total soluble solids and higher titratable acidity compared to V7 berries. In conclusion, our results indicate that the accumulation of tannins in berries during the ripening process results in a reduction in their red color intensity but significantly increases the astringency taste, thereby degrading the berry quality attributes. This study also highlights the association of high nitrogen nutrient levels and a lower crop load with berry astringency in table grapes, paving the way for further research in this area.

Genetic Improvement Methods with an Agroecological Approach for Plant Breeding

Conventional genetic improvement programs play a fundamental role in Brazilian agriculture, transforming this activity into an important contributor to the national economy. However, most of the time it does not serve family farmers, as this cultivation system has different characteristics from conventional agriculture, where it is often composed of agroecological and diversified crops, in a smaller territorial extension, without conditions for carrying out controls using technologies and inputs acquired externally. Thus, participatory breeding aims to align the improvement of cultivar productivity with the provision of biodiversity for family farming. This technique consists of the farmer's ability to select the cultivars best adapted to their environment based on the selection of their seeds, adopting agroecological principles and agrobiodiversity management.

Genetic diversity for agronomic and bromatological traits in forage cactus

This work aimed to estimate the genetic diversity in accessions of Opuntia ficus-indica collected in 13 regions of the semiarid region of Bahia. A total of 65 accessions were evaluated in a randomized complete block design, with three replications, at the Rio Seco experimental station belonging to the State University of Feira de Santana, Amélia Rodrigues-BA. Characterization of the accessions was made through the evaluation of 17 descriptors, namely 11 agronomic and six bromatological. The average Euclidean distance was used to estimate the genetic diversity among accessions. The shortest distances were obtained for accessions from the same collection site while the largest were observed in accessions 54 and 62 (10.32 DE) and 63 and 3 (10.22 DE). The analysis of canonical variables indicated cladodes total number (CTN), plant width (PW), CL, plant height (PH), ether extract (EE), and dry weight (DW) for discard as they presented the lowest contribution of the data set variation. Principal component analysis and K-means method were used to establish the clusters, and the formation of four groups was indicated. The first two principal components captured 52.5% of the total variation present in accessions. The descriptors with the greatest contribution to the variation observed in O. ficus-indica were total cladode photosynthetic area (TCPA), cladode area (CA), and cladodes width (CW). There is divergence between cactus forage accessions collected in the semiarid region of Bahia. This information will allow the use of these materials for the formation of segregating populations in the genetic improvement program of the State University of Feira de Santana. The accessions of groups III and IV should be explored by the forage cactus breeding program, as they presented greater productive potential.

Relationship of the CYP17 gene (T2231A) to milk production and its components in goats

The experiment was conducted at the Ruminant Research Station of the General Authority for Agricultural Research / Ministry of Agriculture on a sample of 53 goats of two breeds (26 Shami goats and 27 local goats), as well as the Scientific Progress Laboratory specialized in biotechnology and genetic material analysis. In order to determine the genotypes and allelic repeats of the CYP17 gene in goats to determine its relationship to milk production and its components, after the completion of the PCR polymerase chain reaction, the results were sent to the Humanizing Genomics Macrogen Company in South Korea to detect the genotypes of the studied area using the sequencing technology, Two genotypes TT and TA were obtained at the site (T2231A), and the percentage of TT genotype was 26.92% for Shami goats. The percentage of TA genotype was 73.08, and the relationship between them was significant (P≥0.05). The allelic frequency of the T allele was And A 0.63 and 0.37, respectively, where the results showed a significant relationship (P≥0.05) between the genotypes and the amount of total milk production and the percentage of solids that are not fatty. The animals carrying the TT genotype recorded the highest amount of production than those carrying the TA genotype, 571.08 ± 48.69 and 432.24 ± 50.56, respectively. Also, the animals carrying the TT genotype outperformed the animals carrying the TA genotype in the percentage of solid non-fat components, which scored 12.79 ± 1.66, and they scored 9.89 ± 1.63. The percentage of TT genotype for domestic goats was 40.74%, and the percentage of genotype TA was 59.26. the relationship between them was significant (P≥0.05), and the allelic frequency of the T and A alleles was 0.70 and 0.30, respectively. The results also showed a significant relationship (P≥0.05) between the genotypes and the amount of total milk production of the local goats, where the animals carrying the TT genotype recorded the highest amount of production than the animals carrying the TA genotype, and it scored 548.15 ± 72.06 and 350.10 ± 47.94, respectively. Thus, the CYP17 gene can be used in genetic improvement programs. Keywords: Goats; CYP17 Gene; Genotype; Milk Production.

Selection of Cordia trichotoma Vell. clones for adventitious rooting and determination of the plantlet quality produced by mini-cuttings

This study aimed to evaluate and define strategies for the selection of C. trichotoma clones with competence for adventitious rooting and production of high-quality plantlets by mini-cuttings. For adventitious rooting, mini-cuttings were treated with 3,000 mg L-1 of indole butyric acid and grown in 110 cm³ tubes, consisting of equal proportions of the commercial substrate and vermiculite. The percentage of rooting, number of roots, and mini-cuttings rooted per mini-stump were evaluated after 30 days of cultivation in a humid chamber. The rooted mini-cuttings were transferred to a shade house and the survival percentage, stem diameter, height, and number of leaves were evaluated at 120 days. Data were analyzed using the restricted maximum likelihood/best linear unbiased prediction (REML/BLUP) method and Pearson´s correlation analysis. The number of rooted mini-cuttings and stem diameter presented the highest repeatability and accuracy values for rooting and plantlet growth, respectively. These traits also presented significant positive correlation estimations with others, indicating the possibility of indirect selection gain. Cordia trichotoma clones can be selected for vegetative propagation, considering the number of rooted mini-cuttings and the stem diameter of the plantlets produced by mini-cutting. Early selection for adventitious rooting and plantlet quality can aid in genetic improvement programs for the development of new cultivars for vegetative propagation via the use of mini-cuttings.

Flowering induction in cassava using photoperiod extension premature pruning and plant growth regulators.

Cassava (Manihot esculenta Crantz) is a vital crop for food and economic security in many regions of the world. Despite the economic and social importance of cassava, challenges persist in developing superior varieties that meet the needs of farmers in terms of agronomic performance, nutritional quality, and resistance to pests and diseases. One of the main obstacles for genetic improvement is the lack of synchronization in flowering and the abortion of young flowers, making planned crosses and progeny production difficult. Therefore, the aim of this study was to evaluate the effect of photoperiod, premature pruning, and growth regulators on cassava flowering under low-altitude conditions in Brazil. Eight cassava clones with contrasting flowering capacity were assessed in Cruz das Almas, Bahia, using two photoperiods (ambient condition and extended photoperiod with red light for 12 hours), premature pruning at the first and second branching levels (with and without pruning), and the application of growth regulators: 0.5 mM 6-benzyladenine (BA) and 4.0 mM silver thiosulfate (STS) (with and without). Plots were assessed weekly for the number of female (NFF) and male (NMF) flowers, height of the first branching (H1B, in cm), number of days to the first branching (ND1B), and the number of branching events up to 240 days after planting (NOB). The extended photoperiod did not promote an increase in the number of flowers but allowed for precocity in cassava flowering, reducing the onset of flowering by up to 35 days, and significantly increasing the number of branches, which is closely related to flowering. The use of pruning and plant growth regulators (PGR) resulted in an increase in NFF from 2.2 (control) to 4.6 and NMF from 8.1 to 21.1 flowers. Therefore, under hot and humid tropical conditions at low altitudes in the Recôncavo of Bahia, manipulating the photoperiod and using premature pruning and plant growth regulators can accelerate cassava flowering, benefiting genetic improvement programs.

INFLUENCE DES PARAMETRES DE REPRODUCTION SUR LA PRODUCTIVITE DES HYBRIDES F2 NAIN X NAIN

The objective of this study was to evaluate some production parameters for the identification of elite Nain. Twenty-seven coconut trees, spread over 2 plots, were selected. A control, Malay Yellow Dwarf (NJM), was added to each plot. The study of the relationship between five variables revealed highly significant correlations between them. The multivariate analyses made it possible to identify among the genotypes, the type 7 individuals as being the most efficient. Individuals of type 7 had the highest averages for number of flowers at bag laying (NFP), number of flowers at bag removal (NFE), number of knotted flowers (NFN) and number of nuts harvested (NNR) compared to types 4, 5 and 6. Pollen germination rates in type 1 (Control) individuals were significantly higher than those of the other four types that did not differ significantly between them. The tests for the prediction of the number of nuts harvested indicated that 48.31% of the fluctuations of seed nuts reaching maturity are attributable to the number of female flowers counted at the installation of the bag, that of the female flowers counted at the bag removal and that of the female flowers tied. The predicted values for the number of mature seed nuts are: Nnoirec = -1.12 – 0.007*Nflepose + 0.012*Nflenlev + 0.408*Nflnou +0.014TG. Individuals of type 7 likely to be elite broodstock can be used in programs of genetic improvement of the coconut for better performance.

Genetic Diversity and Structure of Local Chicken Populations Raised in Five Agroecological Zones of Togo

Local chickens are the most commonly raised poultry breed in rural areas of Togo, where they help in alleviating poverty and food insecurity in households. The current study aimed to ensure the sustainable management of this genetic resource by evaluating the genetic diversity, phylogenetic relationships, and population structure of local chicken populations from five agroecological zones (Dry Savannah, Atakora, Forest, Wet Savannah, and Littoral) in Togo. Genotyping was carried out using 15 microsatellite markers on 30 unrelated individuals per agroecological zone. Genetic diversity was assessed by estimating the number of alleles per locus, observed heterozygosity, unbiased expected heterozygosity, and the polymorphic information content (PIC). The genetic structure of the populations was analyzed using a Bayesian-based approach. The results revealed a high genetic diversity but weak population structuring among local chickens. Moreover, 98 alleles were detected in all population groups, varying from 3 to 12 per locus, with an average of 6.53 ± 2.67 alleles per locus. The PIC values varied from 0.436 to 0.690, with an average of 0.550 ± 0.087. The mean number of alleles per population across all markers ranged from 4.4 ± 1.4 (Dry Savannah) to 5.4 ± 2.0 (Forest). The unbiased expected heterozygosity was high and varied from 0.58 ± 0.07 (Atakora) to 0.65 ± 0.11 (Forest), while that observed varied between 0.46 ± 0.09 (Dry Savannah) and 0.57 ± 0.14 (Forest). All populations deviated significantly from the Hardy-Weinberg equilibrium. Across populations, FIT, FIS, and FST fixation indices were 0.150, 0.132, and 0.021, respectively. The genetic distances were low and varied from 0.022 (between Atakora and Dry Savannah) to 0.045 (between Atakora and Forest). These results could be used in potential genetic improvement programs or the preservation of local chickens in Togo.

Comprehensive Organ-Specific Profiling of Douglas Fir (Pseudotsuga menziesii) Proteome.

The Douglas fir (Pseudotsuga menziesii) is a conifer native to North America that has become increasingly popular in plantations in France due to its many advantages as timber: rapid growth, quality wood, and good adaptation to climate change. Tree genetic improvement programs require knowledge of a species' genetic structure and history and the development of genetic markers. The very slow progress in this field, for Douglas fir as well as the entire genus Pinus, can be explained using the very large size of their genomes, as well as by the presence of numerous highly repeated sequences. Proteomics, therefore, provides a powerful way to access genomic information of otherwise challenging species. Here, we present the first Douglas fir proteomes acquired using nLC-MS/MS from 12 different plant organs or tissues. We identified 3975 different proteins and quantified 3462 of them, then examined the distribution of specific proteins across plant organs/tissues and their implications in various molecular processes. As the first large proteomic study of a resinous tree species with organ-specific profiling, this short note provides an important foundation for future genomic annotations of conifers and other trees.

Examining the supplementation of exogenous lipid and antioxidant to improve the survivability of post-thaw oocytes in Mediterranean mussels, Mytilus galloprovincialis

The Mediterranean mussel is one of the most important aquaculture species in the world and a key bioindicator for monitoring environmental pollution. In addition to genetic resource germplasm conservation, oocyte cryopreservation could increase opportunities for off-season seed supply and facilitate genetic improvement programs and applications that require gametes year-round, such as pollution assessments using larval development as a biomarker. This study investigated the effect of exogenous lipids and antioxidants on the survivability of post-thaw mussel oocytes by supplementing lipid, antioxidant or their combination in the base cryoprotectant agent (10% ethylene glycol and 7.5% Ficoll® PM 70). The lipids included three polyunsaturated fatty acids (PUFAs), i.e., arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid, one phospholipid [1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)] and the lipid extract from Atlantic salmon (Salmo salar). The antioxidant was α-tocopherol. Results from the chemical tolerance experiment showed that all PUFAs were toxic at a concentration of 0.1 mg/mL or higher. In comparison with the base cryoprotectant agent, the supplement of 0.5 mg/mL POPC or 1 mg/mL α-tocopherol alone increased the relative survival rate of D-stage larvae by approximately 50%, whereas the combination of 0.5 mg/mL POPC and 0.5 mg/mL α-tocopherol increased the relative survival rate of D-stage larvae by approximately 100%. Adding 0.5 mg/mL salmon lipid extract resulted in the highest relative survival rate of D-stage larvae. However, it was not significantly different from the POPC and α-tocopherol combination. In addition, the salmon lipid extract treatment produced twice the number of spat compared with the base cryoprotectant agent. This study reveals that adding lipids and antioxidants could therefore open a novel strategy for improving oocyte cryopreservation success in marine bivalves.

Towards understanding the type and function of indigenous goats: input for genetic improvement and conservation programme

ABSTRACT This study aimed to provide a better understanding of the type, function, and production potential of Central Highland goats. Morphometric measurements were collected from 510 heads of goats. About 17 biologically important structural indices were computed using morphological trait measurements. The data were analyzed using SAS’s general linear model, principal component analysis, and stepwise multiple regression techniques. Body index value indicate that the Central Highland goat’s shape is rectangular, which is good conformation for meat production. The dactyl thorax, transverse pelvic, longitudinal pelvic, relative depth of thorax, and width indices suggest their suitability for meat production. However, proportionality and length indices showed an aptitude for milk production. Besides, the body ratio and depth indices indicate less susceptibility of this goat breed to dust infestation and arthritis, good walking ability, good foraging capability, and move easily in sloppy areas. In conclusion, structural indices showed that Central Highland goats could be classified as having a dual purpose and better aptitude for meat production. The results of this study could be an input for designing genetic improvement and conservation programmes for the sustainable utilization of indigenous goats.

Correlations of betanodavirus load in the brain of experimentally infected sea bass (Dicentrarchus labrax, L.) with varying levels of resistance to viral nervous necrosis

The red-spotted grouper nervous necrosis virus (RGNNV) genotype of Betanodavirus causes significant losses to the European sea bass aquaculture industry. The lack of widely available vaccines against this genotype has led researchers and the industry to investigate other avenues for reducing mortality caused by the disease, such as the selection of resistant stocks. The objectives of this study were: a) to assess the presence of natural resistance in sea bass families propagated in the genetic improvement program of Nireus S.A., Greece and, b) to test an ELISA method able to detect viral coat antigen and measure viral load in the brain of tested fish. The second objective was to investigate virus antigen fluctuations during the course of the infection and its correlation with disease development, mortality and resistance. Further aspects of disease pathogenesis were investigated. A population of sea bass consisting of 89 families was experimentally infected with an RGNNV genotype of Betanodavirus; mortalities were recorded and brain samples from dead and survived fish were collected. Experimental infection of fish resulted in a typical pattern of mortality development that reached 56%. Different levels of natural resistance between families were found with cumulative mortality ranging from 20% to 86.2%. There was no statistical difference between the weight of dead fish and the resistant and susceptible families, except when extreme phenotypes were tested, indicating that the weight of fish that died was not a significant factor of final mortality. Brain virus load in the population as a whole increased sharply until D6 post-infection and then gradually dropped until the end of the experiment. When the viral load in the population (dead and survived fish) was tested against time of death, no correlation was found. In fish that survived the infection, the virus load remained high. The viral load per mg of brain tissue in samples taken from dead fish was not a factor that influenced family cumulative % mortality. Brain samples from survived fish reproduced the disease after infection of healthy fish. This study revealed a natural resistance of sea bass to Betanodavirus infection. This important finding can be used as an additional tool in reducing the mortality of cultured stocks. Additionally, there was clear evidence that fish surviving infection become subclinical carriers of the pathogen. Apparently, survival may not be associated with mechanisms of viral clearance but to other mechanisms that may suspend viral replication or aid infected cell endurance. These findings may assist in developing future vaccines and stock selection. A combination of effective vaccination and resistant stocks could be the way ahead.

Genetic Variability of Oil Palm in Mexico: An Assessment Based on Microsatellite Markers

Oil palm (Elaeis guineensis Jacq.) has become the largest source of vegetable oil in the world. It is known that all existing genotypes of this species are related, so their genetic variability is considered to be low. In Mexico, all oil palm plantations are located in the southeast of the country, and they are established with different origins seeds, which has caused poor yields and resulted in the need to establish a genetic improvement program. Therefore, in this study, the extent of genetic diversity among 151 oil palm accessions from all producing regions of Mexico was assessed with twenty simple sequence repeats (SSRs) and seven random amplified microsatellite (RAM) markers. The markers utilized proved to be useful in revealing high existing genetic variability, with a total of 1218 and 708 alleles detected and polymorphic information content (PIC) of 0.96 and 0.91 for RAM and SSR, respectively. The genetic distance among all accessions of oil palm collected ranged between 31% and 82% for similarity. Accessions from Tabasco and Veracruz presented the greatest and smallest genetic diversity, respectively. These results can allow breeding strategies to be established for the genetic improvement of this crop in Mexico.

Using the community-based breeding program (CBBP) model as a collaborative platform to develop the African Goat Improvement Network-Image collection protocol (AGIN-ICP) with mobile technology for data collection and management of livestock phenotypes.

Introduction: The African Goat Improvement Network Image Collection Protocol (AGIN-ICP) is an accessible, easy to use, low-cost procedure to collect phenotypic data via digital images. The AGIN-ICP collects images to extract several phenotype measures including health status indicators (anemia status, age, and weight), body measurements, shapes, and coat color and pattern, from digital images taken with standard digital cameras or mobile devices. This strategy is to quickly survey, record, assess, analyze, and store these data for use in a wide variety of production and sampling conditions. Methods: The work was accomplished as part of the multinational African Goat Improvement Network (AGIN) collaborative and is presented here as a case study in the AGIN collaboration model and working directly with community-based breeding programs (CBBP). It was iteratively developed and tested over 3years, in 12 countries with over 12,000 images taken. Results and discussion: The AGIN-ICP development is described, and field implementation and the quality of the resulting images for use in image analysis and phenotypic data extraction are iteratively assessed. Digital body measures were validated using the PreciseEdge Image Segmentation Algorithm (PE-ISA) and software showing strong manual to digital body measure Pearson correlation coefficients of height, length, and girth measures (0.931, 0.943, 0.893) respectively. It is critical to note that while none of the very detailed tasks in the AGIN-ICP described here is difficult, every single one of them is even easier to accidentally omit, and the impact of such a mistake could render a sample image, a sampling day's images, or even an entire sampling trip's images difficult or unusable for extracting digital phenotypes. Coupled with tissue sampling and genomic testing, it may be useful in the effort to identify and conserve important animal genetic resources and in CBBP genetic improvement programs by providing reliably measured phenotypes with modest cost. Potential users include farmers, animal husbandry officials, veterinarians, regional government or other public health officials, researchers, and others. Based on these results, a final AGIN-ICP is presented, optimizing the costs, ease, and speed of field implementation of the collection method without compromising the quality of the image data collection.