Genetic Improvement Programs Research Articles

EFFECT OF TEMPERATURE ON ROOTS AND SHOOTS FORMATION IN THREE VANILLA SPECIES (ORCHIDACEAE) UNDER CONTROLLED CONDITIONS

<p><strong>Background. </strong><em>Vanilla planifolia</em> is a species of commercial and cultural importance. However, its growth and development could be affected by the increase in temperature caused by climate change. In contrast, <em>V.</em> <em>pompona</em> and <em>V. insignis</em> are wild species with potential use as aromatic species and they show greater tolerance to prolonged exposure to high temperatures. <strong>Objective. </strong>To determine the effect of temperature on the development of roots and shoots of <em>V.</em> <em>planifolia</em>, <em>V.</em> <em>pompona</em> and <em>V. insignis</em> under controlled conditions. <strong>Methodology.</strong> Cuttings of approximately 20 cm with two nodes were grown at 25, 32, 35 and 38 °C under controlled conditions, with a relative humidity of 100%, for six weeks. To evaluate cutting development, the number of roots produced was recorded, as well their length, their growth rate and their diameter. Likewise, the number of shoots generated, their length, growth rate and diameter were also counted. The experimental design was completely random, and the data were analyzed using Tukey<em> post hoc </em>analysis of variance (<em>P</em> < 0.05). <strong>Results. </strong>The increase in temperature affected the promotion and root growth in <em>V. planifolia</em>, which showed<strong> </strong>the greatest length at 25 °C (20.64 ± 0.26 cm) and the lowest value at 35 °C (1.22 ± 0.49 cm), contrary to <em>V. insignis</em>, where the increase in temperature at 35 °C favored root elongation (4.76 ± 0.07 cm), while the lowest growth was observed at 25 °C (1.74 ± 0.13 cm). <em>V. pompona</em> did not present significant differences in root growth at the three temperatures evaluated. Similarly, the increase in temperature showed a distinct influence on the promotion and growth of the shoot. <em>V. planifolia</em> only produced shoots at 32 °C (8.4 ± 0.4 cm) and <em>V. pompona</em> generated them at 32 and 35 °C, being those of greater length at 35 °C (3.3±0.13 cm) and did not produce at 25 °C; while <em>V. insignis</em> showed the highest shoot growth at 25 °C (7.22 ± 0.2 cm) and the lowest at 32 °C (6.56 ± 0.12). At 38 °C, 100% mortality was observed in the three species. <strong>Implications.</strong> The growth of roots and shoots of <em>V. planifolia</em> are affected by an increase in temperature above 32 °C, therefore, conservation and genetic improvement programs are needed that could start from the qualities that <em>V. pompona </em>and <em>V. insignis </em>showed. <strong>Conclusion. </strong>Temperature ranges between 25 and 35 °C have a differential effect on the promotion and growth of roots and shoots for the species <em>V. planifolia</em>, <em>V. insignis</em> and <em>V. pompona</em>.</p>

DIVERSIDAD DEL MAÍZ EN TRES ZONAS GEOMORFOLÓGICAS DE YUCATÁN, MÉXICO

<p><strong>Background: </strong>Maize (<em>Zea mays</em> L.) is the main sustenance in the daily diet of Mexican families. As a crop, it is one of the most important in the country of Mexico, and in Yucatan state, it is grown under rainfed conditions in milpas with no mechanizable lands. In this study, an analysis of the phenotypic variability from cob collects of native maize from Yucatan state was carried out, with ethnobotanical information collected within passport data. <strong>Objectives:</strong> To introduce the genetic diversity of maize into a germplasm bank, to know the genetic diversity of native populations based on the characteristics of cob, to know its distribution, to find the potential populations in each collection area for its use in genetic improvement programs. <strong>Methodology: </strong>66 Tuxpeños, 13 Dzit bacal, 6 Nal tel, 13 Xmejen nal, and 2 Nal xoy were collected in the southern, central, and eastern regions of the state, from January to March 2020, by sampling the four cardinal points in each community visited. A vector map of collections in Yucatan was developed and quantitative data of 13 biometric cob variables were recorded in 100 populations (crop cycles: late n=68; intermediate n=26; early n=6), a general data analysis of variance (ANOVA) and by crop cycles were made, principal component analysis (PCA), hierarchically clustered with the average linkage method and discriminant analysis were made. Qualitative data from ethnobotanical surveys with mixed questions applied to milperos at the time of collection are presented. <strong>Results: </strong>The diversity of native maize in Yucatan is made up of three main groups based on the crop cycle: late, intermediate, and early. The southern and eastern regions of Yucatan preserve greater diversity, representing 44 and 40% of the total collections, respectively. There were significant differences in all ear variables; in a late growth cycle, only the grain thickness did not show differences between populations, and in the early growth cycle the grain thickness, width, and length variables were not significant. The PCA explained 80% of the total variation, seven different groups were formed, with greater differentiation in early maize Nal tel, intermediate Xmejen nal and Dzit bacal, contrary to the Tuxpeños late maize. Ten promising populations were identified for selection in each geomorphological region: eight correspond to the southern, two to the eastern, and one to the center of Yucatan state. The main factors to select for sowing corn in the region are: white and yellow maize for yield, the resistance to weevil attack for red maize, and the perception of color and palatability in purple maize. <strong>Implications: </strong>A complete phenotypic characterization in the field is required with a special interest in red-pigmented maize.<strong> Conclusions: </strong>The interest of the milperos in conserving and sowing the different native maize are based on the color of the grain, the benefits and uses that they can obtain from them, which determine the planting area in the milpas of the different races/varieties of maize. Red grain maize is being planted in a lower area in relation to other colors. The southern and eastern geomorphological regions showed a genetic flow between them.</p>

Morphological and Ecogeographical Diversity of the Andean Lupine (Lupinus mutabilis Sweet) in the High Andean Region of Ecuador

Promoting food security is one of the 17 Sustainable Development Goals (SDGs) proposed by the United Nations General Assembly, with a target date of 2030. Human nutrition based on legume consumption is essential to ensuring food security while reducing greenhouse gas emissions associated with nitrogen fertilizer use. Moreover, preserving legume biodiversity is critical to increasing agricultural resilience against climate change. The Andean lupine or “tarwi” (Lupinus mutabilis Sweet) is a legume native to the Andean region with high nutritional importance. Morphological characterization processes allow the determination of local agro-biodiversity and the identification of promising materials for genetic improvement programs. In the present investigation, 173 accessions of Andean lupine from the Germplasm Bank of INIAP, Ecuador, were evaluated. Thirteen quantitative and fifteen qualitative descriptors were used in the characterization. The results revealed that the genetic variability of the Andean lupine is represented by the conformation of four groups of accessions. Among those groups, two accessions stand out for having small plants and high yields, factors that could be used for genetic improvement processes or be reintroduced into farmers’ fields as they represent an option for the production, consumption, and marketing of the local germplasm of this relevant ancient crop. A phenotypic diversity map of the cultivated tarwi explained that areas with high morphological diversity are not completely identical to areas with high ecogeographic diversity. The distribution of the genetic variability of species appears to be more related to cultural aspects than environmental conditions.

Response of Conilon coffee cultivars in the central cerrado in irrigated management pivot sprinkler

Coffee cultivation has been growing significantly, since the world demand has increased considerably in recent decades. Among the coffees, conilon coffee has been a good option for cultivation in the Cerrado, as it presents good production in areas of high altitudes, however the study of canefora coffee in irrigated system in the Cerrado is something recent. The work aimed to analyze the productive potential of superior clones of caneflower coffee cultivars through agronomic performance under irrigated conditions in the Central Cerrado and to select the outstanding clones for future use in genetic improvement programs. The experiment was conducted in the experimental area of Embrapa Cerrados in Planaltina - DF, in a randomized block design with three replications. The cultivars evaluated were Diamante ES 8112, ES 8122 - Jequitibá and Centenária ES 8132, each composed of 9 clones totaling 27 conilon coffee genotypes, with different maturation times. The clones were planted with 3.5 x 0.5 m spacing in a center pivot irrigation system. The characteristics evaluated from two harvests (2018 and 2020) were: average grain yield (PMG); percentage of grains retained in sieve 16 (sieve > 16); percentage of mocha grains (GMO); average plant height (AP), crown projection (PC) and number of productive nodes (NNP). Data were submitted to analysis of variance and means were grouped by the Scott-Knott test at 5% significance level. Based on the result of the analysis of variance, there was a significant difference in all maturation cycles for the traits PMG, sieve > 16, GMO, AP, PC and NNP. The averages of grain size percentage in sieve size 16 or larger were distinct in the 3 groups analyzed. It was found that the averages of production of processed grains (PMG) were different in the two years evaluated, due to the environmental conditions imposed from one year to another. Within the clones, clone 207 presented the highest grain yield value in 2020 with 12493 kg ha-1. There was genotypic variability in the behavior of clonal varieties and their respective clones, being able to select clones and use them within breeding programs, for targeted crosses and subsequent development of new cultivars.

Molecular insight into genetic differentiation, population structure and banding pattern analysis of Bambara groundnut (Vigna subterranea [L.] Verdc.) linked with inter simple sequence repeats (ISSR).

A set of 44 selected Bambara groundnut (Vigna subterranea [L.] Verdc.) accessions was sampled from 11 distinct populations of four geographical zones to assess the genetic drift, population structure, phylogenetic relationship, and genetic differentiation linked with ISSR primers. The amplification of genomic DNA with 32 ISSR markers detected an average of 97.64% polymorphism while 35.15% and 51.08% polymorphism per population and geographical zone, respectively. Analysis of molecular variance revealed significant variation within population 75% and between population 25% whereas within region 84% and between region 16%. The Bidillali exposed greater number of locally common band i.e., NLCB (≤ 25%) = 25 and NLCB (≤ 50%) = 115 were shown by Cancaraki while the lowest was recorded as NLCB (≤ 25%) = 6 and NLCB (≤ 50%) = 72 for Roko and Maibergo, accordingly. The highest PhiPT value was noted between Roko and Katawa (0.405*) whereas Nei's genetic distance was maximum between Roko and Karu (0.124). Based on Nei's genetic distance, a radial phylogenetic tree was constructed that assembled the entire accessions into 3 major clusters for further confirmation unrooted NJ vs NNet split tree analysis based on uncorrected P distance exposed the similar result. Principal coordinate analysis showed variation as PC1 (15.04%) > PC2 (5.81%). The current study leads to prompting the genetic improvement and future breeding program by maximum utilization and better conservation of existing accessions. The accessions under Cancaraki and Jatau are population documented for future breeding program due to their higher genetic divergence and homozygosity.

Association Between of the Growth Hormone Gene GH-1 with Growth Indicators of Common Carp Cyprinus carpio L. in Three Different Ecosystems

This study was conducted in the central of health laboratory/Animal and Fish Resource Research Center, Agricultural Research Department, Ministry of Science and Technology, for the period from 15/8/2021 to 15/11/2021 in order to investigate the polymorphism of the growth hormone gene GH-1 and its relationship to the productive performance (body weight, total length, age and case factor) of common carp Cyprinus carpio, in 90 fish representing three different ecosystems (30 fish for each site) including floating cages, ponds, and the environment of the Tigris River, south of Baghdad, with an average weight of (975-1517±150) g. Some physical and chemical measurements of water were measured, including temperature, dissolved oxygen concentration, pH, and salinity. These fish were transferred to the laboratory, and the weight, total length, and age of each fish were measured, as well as DNA extraction for the purpose of amplifying the size of a segment (459pb) of the growth hormone gene that includes exon 4, intron 4, and exon 5 by polymerase chain reaction PCR using primers designed for this gene. The genotypes of the growth hormone gene were investigated using the Single-Stranded Conformation Polymorphism (SSCP) technique, and the produced bands were compared to distinguish different genotypes of the gene by the electrophoresis method. The results showed that the water temperature was close to the environmental systems under study and ranged between (25.4-27 ± 0.50), the rates of dissolved oxygen concentration were (6.5 ± 0.09) mg/l, pH (7.0 ± 0.02) and salinity 0.8 g/l higher in ponds compared to the lowest value of them in the river. The analysis of the SSCP technique revealed the presence of six different genotypes of this hormone, including A, B, C, E, F, and H with a frequency of 24.4, 5.6, 15.6, 15.6, 16.4, and 22.4, respectively, for the fish community in the studied sites. The H genotype was significantly (P< 0.05) superior in the floating cages in the average body weight (1600 ± 0 g) and the relative case coefficient (2.5 ± 0). significant differences were observed in the average total body length and age, according to the multiplicity of genotypes. We conclude from this study an improvement in the growth and health status of common carp in cages and ponds compared to the river at the probability level (P<0.05) and the possibility of focusing on the polygenic genotypes of the growth hormone gene and adopting the H genotype as a guide for selecting fish mothers in genetic improvement programs for artificial propagation and achieving the largest economic return from fish breeding projects.

CIP-PODEROSA CROCANTE, CIP-PODEROSA POLLERA, and CIP-PODEROSA WATIA: New Potato Varieties for Family Farming with Resistance to Late Blight and High Quality for the Frying Industry

Abstract Three new potato varieties: CIP-PODEROSA CROCANTE, CIP-PODEROSA POLLERA and CIP-PODEROSA WATIA were generated through traditional breeding as healthy and sustainable potato varieties, as compared with popular Peruvian potato varieties INIA 303-CANCHAN and UNICA, to improve living standards of small and medium scale potato producers in Peru and other developing countries. CIP-PODEROSA CROCANTE has high horizontal resistance to late blight (LB), high tuber yield, excellent quality for frying in French fries, red skin, oval tuber shape, cream flesh and superficial eyes, with crispy texture, adapted from 0 to 3700 m above sea level (m.a.s.l.); CIP-PODEROSA POLLERA has high horizontal resistance to LB, yellow skin with blue around the superficial eyes, elongated oval tuber shape, yellow flesh, it is suited to accompany grilled chicken (“Pollo a la brasa”) a typical dish in Peru, adapted from 2000 to 3700 m.a.s.l.; and CIP-PODEROSA WATIA, which in addition to resistance to LB and quality for frying, has excellent aptitude for baking, superficial eyes, light red skin, cream flesh, and is adapted from 0 to 3700 m.a.s.l. These varieties were released in 2022 and officially registered in the national registry of commercial varieties of Peru in 2023. They have low content of glycoalkaloids and acrylamides, require lower use of fungicides, and therefore present higher economic profitability. These varieties can also be used in other countries as parental material in genetic improvement programs or evaluated under regional environments to be registered as new varieties.

Quantitative trait loci and candidate genes for physico-chemical traits related to tuber quality in greater yam (Dioscorea alata L.).

Starch, dry matter content (DMC), proteins, and sugars are among the major influences on yam tuber quality. Genetic improvement programs need simple, rapid, and low-cost tools to screen large populations. The objectives of this work were, using a quantitative trait loci mapping approach (QTL) on two diploid full-sib segregating populations, (i) to acquire knowledge about the genetic control of these traits; (ii) to identify markers linked to the genomic regions controlling each trait, which are useful for marker-assisted selection (MAS); (iii) to validate the QTLs on a diversity panel; and (iv) to identify candidate genes from the validated QTLs. Heritability for all traits was moderately high to high. Significant correlations were observed between traits. A total of 25 QTLs were identified, including six for DMC, six for sugars, six for proteins, and seven for starch. The phenotypic variance explained by individual QTLs ranged from 14.3% to 28.6%. The majority of QTLs were validated on a diversity panel, showing that they are not specific to the genetic background of the progenitors. The approximate physical location of validated QTLs allowed the identification of candidate genes for all studied traits. Those detected for starch content were mainly enzymes involved in starch and sucrose metabolism, whereas those detected for sugars were mainly involved in respiration and glycolysis. The validated QTLs will be useful for breeding programs using MAS to improve the quality of yam tubers. The putative genes should be useful in providing a better understanding of the physiological and molecular basis of these important tuber quality traits. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Genetic trends and multivariate interrelationships for grain quality of irrigated rice genotypes

For genetic improvement programs, researches with multivariate approaches in rice are fundamental, to define genetic trends, clusters and correlations of agronomic characters that together help selection procedures. This work aimed to reveal the agronomic performance, trends and genetic interrelationships of grain quality based on multivariate models applied to elite lines of irrigated rice. The experiment took place in the 2017/2018 harvest, held at Estação Experimental Terras Baixas (ETB), of Embrapa Clima Temperado. The study used randomized blocks design, with three replications. There were fifteen F6 lines and four control cultivars. Evaluation of intrinsic physical quality attributes with the aid of S21 grain statistical analyzer, as well as grain yield and mill yield (whole and broken grains). Performance of analysis of variance, genetic parameters and Scott Knott cluster test, linear correlation, canonical correlations, cluster analysis via generalized Mahalanobis distance, using the Toucher method, in addition to BIPLOT principal component analysis. The results showed that PH18502 and PH18701 strains presented better agronomic performance for the studied characters, by univariate analysis. The linear and canonical correlations presented demonstrate potential in the direction of selection of multiple characters and point to the possibility of indirect selection among the relevant agronomic characters for the production chain of irrigated rice.

K252a inhibition of sperm viability for efficient crossbreeding of hermaphroditic bivalves

Bivalve mollusks are economically important shellfish, representing 56.3% of aquaculture production. Crossbreeding is a popular approach for the genetic improvement of aquaculture species, including bivalves. However, it is difficult for simultaneous hermaphrodites due to the difficulty in collecting unfertilized oocytes. Male infertility or subfertility could be a solution. Considering that protein phosphorylation is critical in spermatogenesis, we investigated the effects of the protein kinase inhibitor K252a on germ cell development, gamete quality and embryonic/larval development of the simultaneously hermaphroditic scallop Argopecten irradians and evaluated its feasibility in crossbreeding. The results showed that 20% K252a injection at the gonad growth stage led to significant decreases in sperm number and progressive motility rate. Abnormal axoneme arrangement in flagella may have caused reduced sperm motility. Normal oocytes fertilized with K252a-treated sperm showed significant decreases in fertilization rate (38.24%), cleavage rate (83.42%) and D-stage survival rate (15.93%), and K252a-treated oocytes did not show obvious defects in early development. Interspecific hybridization using K252a-treated A. irradians fertilized with Argopecten purpuratus sperm resulted in a 3.19-fold increase in the hybrid ratio (67%) over that of the control group (16%). Our study indicated that K252a influenced sperm development without affecting oocytes in A. irradians, indicating that K252a treatment may facilitate the mass production of crossbreeds and hybrids for simultaneous hermaphrodites. The approach reported here will greatly assist in genetic improvement programs for mollusk hermaphrodites.

Agronomic, Sensory and Essential Oil Characterization of Basil (Ocimum basilicum L.) Accessions

Basil (Ocimum basilicum L.) is one of the main condiments for fresh consumption and essential oil production. The aim of the present work was to assess the agronomic characterization and analyze the essential oil of 63 basil accessions. The experiment was conducted in two stages in a greenhouse using vases and a hydroponic cultivation system. Oil extraction was performed employing the Soxhlet method. There was a significant variation in the agronomic characteristics among the evaluated accessions. The estimated total contents of essential oils ranged from 0.05 to 0.40%, and the major volatile fraction was methyl-eugenol. In the present study, accessions with superior performance compared to commercial varieties were found. Accession BL11 presented agronomic characteristics suitable for cultivation in a hydroponic system due to its better plant structure and late flowering. Accession BL24 stood out for essential oil extraction, producing 17.6% of linalool and a high intensity of color and odor. Accessions BL11 and BL24 presented market potential, given their higher mass productivity and higher essential oil yield, respectively. These accessions can be made available as new varieties in addition to being used in genetic improvement programs for this species.

Impact of selection for growth and stocking density on Nile tilapia production in the biofloc system

Environmentally friendly aquaculture systems such as the biofloc technology (BFT) are gaining prominence, as well as the use of genetically superior fish and better adapted strains. However, sustainable systems must be economically efficient as well. According to literature, Nile tilapia takes a longer time to reach commercial weight in BFT if compared to traditional systems, reducing profitability. A better adapted strain, with faster growth, feed efficiency and tolerance to the intensive conditions of the BFT, should be an alternative to improve the profitability of the system. This study evaluated the economic and growth performance of Nile tilapia populations from two distinct generations, the base generation (G0) and generation 5 (G5), from a genetic improvement program based on genetic selection for body weight in BFT and recirculating aquaculture system, under two different stocking densities (12.5 and 37.5 ind. ‧ m−3) in BFT. A total of 320 male fingerlings (160 from G0 and 160 from G5) were randomly distributed in a factorial arrangement (2 × 2, four treatments) with four replicates (800 L tanks) for each treatment (16 sample units in total). The means were compared using two-way ANOVA and SNK's test (p < .05) and the confidence interval (95%) of the differences between them. The water management measures were enough to keep the water indicators within the acceptable ranges for tilapias. Survival rate was high (> 90%) for all treatments. The daily weight gain (DWG) was greater for G5 compared to G0 and resulted in a reduction of >57 days in slaughter time (750 g of harvested weight) for G5 compared to G0 and a 0.22 reduction in feed conversion ratio. The G5 promoted an average reduction of US$ 246.38 ‧ 100 m−3 for total operating cost and added US$ 275.97 ‧ 100 m−3 in operating profit compared to G0. Considering the economic analysis in relation to one ton of tilapia produced, G5 reduced the total operating cost and increased the operating profit only in the lowest stocking density. The increase in stocking density reduced the DWG for both generational groups, resulting in an increase of average time to slaughter of 43.61 days, however, 37.5 tilapia ‧ m−3 promoted a larger operating profit per 100 m−3 (+ US$ 832.60) and per ton of tilapia produced (+ US$ 338.90 for G0 and + US$ 148.39 for G5). This study demonstrates the importance of using genetically improved tilapia together with an adequate stocking density management to achieve better productivity and to make economically more viable an environmentally friendly system.

Evolutionary assessment of SQUAMOSA PROMOTER BINDING PROTEIN-LIKE genes in citrus relatives with a specific focus on flowering

Phase transition and floral induction in citrus requires several years of juvenility after germination. Such a long period of juvenility has been a major hindrance to its genetic improvement program. Studies have shown that miR156 along with its downstream genes SQUAMOSA PROMOTER BINDING PROTEINS (SBP) and SBP-LIKE (SPL) mediate the phase transition and floral induction process in plants. Our current study has systematically analyzed SPLs in 15 different citrus-related species, systematically annotated them based on their close homology to their respective Arabidopsis orthologs, and confirmed the functional attributes of the selected members in floral precocity. The majority of the species harbored 15 SPLs. Their cis-element assessment suggested the involvement of the SPLs in diverse developmental and physiological processes in response to different biotic and abiotic cues. Among all, SPL5, SPL9, and SPL11 stood out as consistently differentially expressed SPLs in the adult and young tissues of different citrus-related species. Independent overexpression of their F. hindsii orthologs (FhSPL5, FhSPL9, and FhSPL11) brought an enhanced expression of endogenous FLOWERING LOCUS T leading to the significantly precocious flowering in transgenic Arabidopsis lines. Future study of the genes in the citrus plant itself is expected to conclude the assessments made in the current study.Graphical

Genetic diversity and population structure of indigenous guinea fowl (Numida meleagris) in Benin using simple sequence repeat markers.

This study aimed to assess the genetic diversity and population structure of 12 guinea fowl phenotypes from three climatic zones (Guinean, Sudano-Guinean and Sudanian) of Benin. A total of 96 adult guinea fowl, aged at least 6months, were selected for blood sampling. Fragment analysis was carried out using 17 polymorphic microsatellite markers. The informative marker combinations revealed a total of 83alleles across all loci, with an average of 5alleles per locus and a mean polymorphic information content (PIC) of0.793. This study showed an observed heterozygosity of0.492. The inbreeding coefficient values ranged from0.086 in white phenotype to0.226 in cinnamon, showing a deficit of heterozygotes, suggesting a moderate inbreeding level. A relatively low population differentiation was observed, with a mean fixation index(Fst) value of0.033. The short genetic distances between phenotypes, unlike the strong genetic identities, revealed high genetic proximity between the 12 phenotypes of indigenous guinea fowl in Benin. These data indicate the existence of a single indigenous guinea fowl population with high intra-population genetic diversity with respect to climatic zones or phenotypes. This study will help in the selection of parental breeding stock for genetic improvement programs, as well as in the conservation for biodiversity maintenance and sustainable use of the indigenous guinea fowl in the study zones in Benin.

Genetic resistance to Ceratocystis fimbriata in elite genotypes of Gmelina arborea

Introduction. In Costa Rica, an incidence of nearly 40 % has been reported for a disease caused by Ceratocystis fimbriata in commercial plantations of Gmelina arborea (melina), which is the second most widely planted forest tree species in the country. Consequently, there is a pressing need to explore genetic material that exhibit resistance to this pathogen. Objective. To evaluate two methods of C. fimbriata inoculation and their effect on elite genotypes of melina, for their use within the melina genetic improvement program at the international forest genetic improvement cooperative GENFORES. Materials and methods. A pathogenicity test was established using the CIF 001 isolate of C. fimbriata under greenhouse conditions, in Santa Clara, San Carlos, Costa Rica. Two inoculation methods were evaluated in five elite genotypes from October 2019 to January 2020. The effect of the pathogen was evaluated by measuring total height development, basal diameter, number of leaves, incidence, and internal injury within the plant. The assessment was conducted at 30, 60, 90, and 120 days. Results. Mortality was observed from day 38 and reached an incidence of 26.7 % at 120 days. The treatment using solid medium displayed the highest incidence percentage. Genotypes 15N and 58 exhibited high susceptibility to the CIF 001 isolate, whereas genotypes 1 and 57 exhibited high tolerance. Based on the results, it was determined that the pathogenicity test of C. fimbriata on melina can be evaluated at 90 days. Conclusion. Solid medium was the most effective method for inoculating melina with C. fimbriata (isolate CIF 001). Evaluations showed the need to assess results at least 90 days after inoculation. Based on the analysis of the internal lesion, genotype 1 was identified as highly resistant to the effect of the pathogen. The inclusion of this genotype as an evaluation technique will substantially enhance the protocol for assessing tolerance to the pathogen.

Longitudinal genome-wide association analysis using a single-step random regression model for height in Japanese Holstein cattle

Growth traits, such as body weight and height, are essential in the design of genetic improvement programs of dairy cattle due to their relationship with feeding efficiency, longevity, and health. We investigated genomic regions influencing height across growth stages in Japanese Holstein cattle using a single-step random regression model. We used 72,921 records from birth to 60 mo of age with 4,111 animals born between 2000 and 2016. The analysis included 1,410 genotyped animals with 35,319 single nucleotide polymorphisms, consisting of 883 females with records and 527 bulls, and 30,745 animals with pedigree information. A single genomic region at the 58.4 megabase pair on chromosome 18 was consistently identified across 6 age points of 10, 20, 30, 40, 50, and 60 mo after multiple testing corrections for the significance threshold. Twelve candidate genes, previously reported for longevity and gestation length, were found near the identified genomic region. Another location near the identified region was also previously associated with body conformation, fertility, and calving difficulty. Functional Gene Ontology enrichment analysis suggested that the candidate genes regulate dephosphorylation and phosphatase activity. Our findings show that further study of the identified candidate genes will contribute to a better understanding of the genetic basis of height in Japanese Holstein cattle.

Genetic Components and Variability Assessment for Grain Yield and Its Accrediting Traits in Maize (Zea mays L.)

Understanding the variability, heritability, and genetic advance in maize is crucial for efficient plant breeding and genetic improvement programmes. The present investigation was conducted to evaluate the various parameters related to assessment of genetic variability and nature of associations among traits affecting grain yield in 80 genotypes of maize (Zea mays L.) at the Research Farm, Department of Genetics &amp; Plant Breeding, College of Agriculture, Gwalior, M.P., India during the Rabi seasons of 2019-20 and Kharif 2020-21. The analysis of variance revealed that highly significant differences exist among the inbred lines, their hybrids and checks for all the characters. Under irrigated and partial irrigated conditions, traits viz., days to 50 percent tasselling and silking, anthesis silking interval (ASI), plant height and membrane stability index exhibited high GCV and PCV. The characters with the highest heritability coupled with higher genetic advance were found for the traits namely: days to 50% silking and 50% tasselling, anthesis silking interval, plant height, numbers of kernel rows per cob, numbers of kernel per rows, seed yield per plant (g), numbers of cobs per plant, days to maturity, cob girth (cm), turgid weight (g), saturation water deficit and membrane stability index for both under irrigated and partial irrigated conditions. High heritability with higher genetic advance as percent of mean indicated the preponderance of additive gene action in controlling the traits. Hence direct selection of such characters would be effective in improving the yield in maize.

Heat stress effects on milk yield traits and metabolites and mitigation strategies for dairy cattle breeds reared in tropical and sub-tropical countries.

Heat stress is an important problem for dairy industry in many parts of the world owing to its adverse effects on productivity and profitability. Heat stress in dairy cattle is caused by an increase in core body temperature, which affects the fat production in the mammary gland. It reduces milk yield, dry matter intake, and alters the milk composition, such as fat, protein, lactose, and solids-not-fats percentages among others. Understanding the biological mechanisms of climatic adaptation, identifying and exploring signatures of selection, genomic diversity and identification of candidate genes for heat tolerance within indicine and taurine dairy breeds is an important progression toward breeding better dairy cattle adapted to changing climatic conditions of the tropics. Identifying breeds that are heat tolerant and their use in genetic improvement programs is crucial for improving dairy cattle productivity and profitability in the tropics. Genetic improvement for heat tolerance requires availability of genetic parameters, but these genetic parameters are currently missing in many tropical countries. In this article, we reviewed the HS effects on dairy cattle with regard to (1) physiological parameters; (2) milk yield and composition traits; and (3) milk and blood metabolites for dairy cattle reared in tropical countries. In addition, mitigation strategies such as physical modification of environment, nutritional, and genetic development of heat tolerant dairy cattle to prevent the adverse effects of HS on dairy cattle are discussed. In tropical climates, a more and cost-effective strategy to overcome HS effects is to genetically select more adaptable and heat tolerant breeds, use of crossbred animals for milk production, i.e., crosses between indicine breeds such as Gir, white fulani, N'Dama, Sahiwal or Boran to taurine breeds such as Holstein-Friesian, Jersey or Brown Swiss. The results of this review will contribute to policy formulations with regard to strategies for mitigating the effects of HS on dairy cattle in tropical countries.

Using a transcriptomic approach to understand poor growth performance in farmed orange-spotted grouper (Epinephelus coioides) larvae: a case study in a commercial hatchery

ABSTRACT The orange-spotted grouper (Epinephelus coioides) is one of the most popular fish in aquaculture due to its high economic value. However, the random occurrence of slow-growing population has led to profit loss. Therefore, transcriptomic analysis was performed to identify the molecular mechanisms involved in driving slow and fast growth, towards addressing this issue. Results show that low expression of developmental genes such as bone morphogenetic protein 1 (BMP 1) and somatostatin (SST), as well as GH/IGF axis-related genes (IGF-1, IGF2, IGFBP1, IGFBP2) and its downstream signalling pathways are correlated with the metabolism and digestive-system-related pathways in slow-growing groupers. Enrichment analysis further revealed that cellular process and biological regulation, as well as several pathways including glycolysis/gluconeogenesis, linoleic acid metabolism, protein digestion and absorption, and cholesterol metabolism were differentially expressed in slow-growing groups. The findings implied that the genomic architecture of growth between the different families raised and the likely problem of inbreeding have led to significantly reduced growth. It is also suggested that better husbandry practices (optimal dietary requirement) is also vital in supporting the success of a genetic improvement programme. These findings recommend growth improvement of orange-spotted groupers via molecular monitoring and artificial selection, complemented by specific dietary feeding.

Phenotypic diversity of date-palm genotypes (Phoenix dactylifera L.) collected from Mundra of Kutch region

A wide range of variability with regard to fruit and pulp characters and taste was observed in date groves in Kutch region of Gujarat (India), which have been developed naturally from seeds. An exploration was undertaken to identify better genotypes of date palm (Phoenix dactylifera) based on their fruit quality and yield-attributing characteristics. A total of 14 fruit samples were collected and data were analysed for fruit characters. Among the different genotypes MDR2 was identified and marked superior with respect to fruiting characteristics like fruit weight (29.86 g), fruit length (53.12 mm) and quality characteristics (TSS 35.17 ºB). In India, the coastal strip of the Kutch region contains the only remaining natural date palm groves, which should be utilised and maintained to be used in future genetic improvement programmes.