Towards progressive regulatory approaches for agricultural applications of animal biotechnology

Traditional breeding techniques, applied incrementally over thousands of years, have yielded huge benefits in the characteristics of agricultural animals. This is a result of significant, measurable changes to the genomes of those animal species and breeds. Genome editing techniques may now be applied to achieve targeted DNA sequence alterations, with the potential to affect traits of interest to production of agricultural animals in just one generation. New opportunities arise to improve characteristics difficult to achieve or not amenable to traditional breeding, including disease resistance, and traits that can improve animal welfare, reduce environmental impact, or mitigate impacts of climate change. Countries and supranational institutions are in the process of defining regulatory approaches for genome edited animals and can benefit from sharing approaches and experiences to institute progressive policies in which regulatory oversight is scaled to the particular level of risk involved. To facilitate information sharing and discussion on animal biotechnology, an international community of researchers, developers, breeders, regulators, and communicators recently held a series of seven virtual workshop sessions on applications of biotechnology for animal agriculture, food and environmental safety assessment, regulatory approaches, and market and consumer acceptance. In this report, we summarize the topics presented in the workshop sessions, as well as discussions coming out of the breakout sessions. This is framed within the context of past and recent scientific and regulatory developments. This is a pivotal moment for determination of regulatory approaches and establishment of trust across the innovation through-chain, from researchers, developers, regulators, breeders, farmers through to consumers.

Genomics Associated Interventions for Heat Stress Tolerance in Cool Season Adapted Grain Legumes

Cool season grain legumes occupy an important place among the agricultural crops and essentially provide multiple benefits including food supply, nutrition security, soil fertility improvement and revenue for farmers all over the world. However, owing to climate change, the average temperature is steadily rising, which negatively affects crop performance and limits their yield. Terminal heat stress that mainly occurred during grain development phases severely harms grain quality and weight in legumes adapted to the cool season, such as lentils, faba beans, chickpeas, field peas, etc. Although, traditional breeding approaches with advanced screening procedures have been employed to identify heat tolerant legume cultivars. Unfortunately, traditional breeding pipelines alone are no longer enough to meet global demands. Genomics-assisted interventions including new-generation sequencing technologies and genotyping platforms have facilitated the development of high-resolution molecular maps, QTL/gene discovery and marker-assisted introgression, thereby improving the efficiency in legumes breeding to develop stress-resilient varieties. Based on the current scenario, we attempted to review the intervention of genomics to decipher different components of tolerance to heat stress and future possibilities of using newly developed genomics-based interventions in cool season adapted grain legumes.

Adaptation of microclones of blackberries to in vivo conditions

The results of studying the effect of mineral fertilizing on rhizogenesis and the development of aboveground organs of regenerant plants of blackberry thornless adaptable to in vivo conditions in the laboratory of selection, vegetable growing and horticulture, cloning “UNITS” Agrotechnopark “of Belgorod State Agrarian University are presented. Regenerated plants of thornless blackberry cultivar Agavam were adapted to in vivo conditions in a peat-perlite mixture with the addition of microelements and growth regulator root 16 days earlier than in the control. An active growth of the aboveground part and roots of regenerated plants of thornless blackberry was noted on the 21st day, in the control - on the 42nd day after the start of adaptation. By the end of the rooting stage on the 24th day, the regenerant plants formed an aerial part of two pairs of leaves 22 mm high and a developed root system - 37 mm. The mineral and hormonal composition of nutrient media for the cultivation of thornless blackberries has been optimized, an effective combination of physical and chemical factors at different stages of micropropagation has been determined, which enhance the proliferation of shoots and roots, and the dependence of the efficiency of adaptation of regenerated plants to in vivo conditions has been established. Along with traditional breeding methods, new opportunities for solving the problem of thorn-free blackberry varieties are provided, along with traditional breeding methods, which make it possible to accelerate the process of obtaining valuable planting material to provide the population and the processing industry with valuable berry products.

Classical Genetics and Traditional Breeding in Cucumber (Cucumis sativus L.)

Rapid progress has been made in classical genetics and traditional breeding in cucumber for various quantitative and qualitative traits which greatly benefited the development of superior varieties suitable for open field and protected cultivation. The different breeding methods like plant introductions, hybridizations, pedigree selection, recombination breeding and marker assisted selection have been employed successfully in developing superior varieties and F1 hybrids. The development of new varieties with earliness, high-yield and resistance to diseases (powdery mildew, downy mildew and tolerant to virus) through selection of superior parental lines followed by hybridization and marker assisted introgression of desired genes was a game changer in cucumber breeding. The exploitation of gynoecious sex along with parthenocarpic traits in traditional breeding has made revolution in cucumber cultivation throughout the world which enabled the adoption of cucumber crop by farming community on large scale. Molecular markers technology could be exploited to overcome the obstacle of traditional breeding by accelerating the breeding cycle and selection of desirable traits. The high density genetic maps for various traits have been constructed in cucumber to detected quantitative traits loci (QTLs) for genetic enhancement in different market classes of cucumber. Therefore, this chapter highlighted the concepts of genetic foundations for advancement made in cucumber breeding.

Development of a gRNA-tRNA Array of CRISPR/Cas9 in Combination with Grafting Technique to Improve Gene Editing Efficiency of Sweet Orange

Sweet orange is one of the most popular fruit crops worldwide. Traditional breeding approaches in sweet orange is impracticable due to the apomixis and long juvenility, making it difficult to obtain hybrids and selection of ideal genotypes. The development of targeted genome engineering technologies made it possible for the precise modification of target genes. Recently, a more efficient gene editing tool has been emerged based on the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) system (Bhaya et al. 2011). The development of CRISPR/Cas9 technology is promising to accelerate the process of genetic improvement in perennial crops.

Redefining Bean Iron Biofortification: A Review of the Evidence for Moving to a High Fe Bioavailability Approach

Iron biofortification of the common bean (Phaseolus vulgaris) commenced in earnest ~18 years ago. Based on knowledge at the time, the biofortification approach for beans was simply to breed for increased Fe concentration based on 3 major assumptions: (1) The average bean Fe concentration is ~50 μg/g; (2) Higher Fe concentration results in more bioavailable Fe delivered for absorption; (3) Breeding for high Fe concentration is a trait that can be achieved through traditional breeding and is sustainable once a high Fe bean sample is released to farmers. Current research indicates that the assumptions of the high Fe breeding approach are not met in countries of East Africa, a major focus area of bean Fe biofortification. Thus, there is a need to redefine bean Fe biofortification. For assumption 1, recent research indicates that the average bean Fe concentration in East Africa is 71 μg/g, thus about 20 μg/g higher than the assumed value. For assumption 2, recent studies demonstrate that for beans higher Fe concentration does not always equate to more Fe absorption. Finally, for assumption 3, studies show a strong environment and genotype by environment effect on Fe concentration, thus making it difficult to develop and sustain high Fe concentrations. This paper provides an examination of the available evidence related to the above assumptions, and offers an alternative approach utilizing tools that focus on Fe bioavailability to redefine Fe biofortification of the common bean.

Genomic selection and genetic gain for nut yield in an Australian macadamia breeding population

Background Improving yield prediction and selection efficiency is critical for tree breeding. This is vital for macadamia trees with the time from crossing to production of new cultivars being almost a quarter of a century. Genomic selection (GS) is a useful tool in plant breeding, particularly with perennial trees, contributing to an increased rate of genetic gain and reducing the length of the breeding cycle. We investigated the potential of using GS methods to increase genetic gain and accelerate selection efficiency in the Australian macadamia breeding program with comparison to traditional breeding methods. This study evaluated the prediction accuracy of GS in a macadamia breeding population of 295 full-sib progeny from 32 families (29 parents, reciprocals combined), along with a subset of parents. Historical yield data for tree ages 5 to 8 years were used in the study, along with a set of 4113 SNP markers. The traits of focus were average nut yield from tree ages 5 to 8 years and yield stability, measured as the standard deviation of yield over these 4 years. GBLUP GS models were used to obtain genomic estimated breeding values for each genotype, with a five-fold cross-validation method and two techniques: prediction across related populations and prediction across unrelated populations. Results Narrow-sense heritability of yield and yield stability was low (h2 = 0.30 and 0.04, respectively). Prediction accuracy for yield was 0.57 for predictions across related populations and 0.14 when predicted across unrelated populations. Accuracy of prediction of yield stability was high (r = 0.79) for predictions across related populations. Predicted genetic gain of yield using GS in related populations was 474 g/year, more than double that of traditional breeding methods (226 g/year), due to the halving of generation length from 8 to 4 years. Conclusions The results of this study indicate that the incorporation of GS for yield into the Australian macadamia breeding program may accelerate genetic gain due to reduction in generation length, though the cost of genotyping appears to be a constraint at present.

Development parameters of the latent period as a response of rubber tree resistance to South American leaf blight

ABSTRACT The major phytosanitary problem for rubber tree cultivation in Brazil is the disease known as South American leaf blight, caused by the fungus Microcyclus ulei. Its symptoms manifest in young leaves and cause intense defoliation, resulting in reduced latex production and even the death of susceptible plants. Thus, this disease consists in a constant threat to East Asian plantations. As worldwide traditional breeding programs have evolved, interspecific hybrid clones have currently been used for planting. They are more productive and show better resistance to pathogens. However, traditional breeding programs have not led to significant progress in resistance to South American leaf blight since the selection is directed to clones with complete resistance. In this pathosystem, horizontal or partial resistance (HR) and vertical or complete resistance (VR) can act simultaneously, evidencing their complexity and difficult quantification. This study aimed to: characterize the foliar lesion type in Hevea sp. X M. ulei pathosystem; verify the clonal susceptibility to pathogens; analyze the infection frequency for resistance quantification in Hevea sp. x M. ulei pathosystem, and recommend differentiating rubber tree clones to quantify M. ulei races in Brazil. The monocyclic parameters (latent period and lesion diameter) are applicable for resistance quantification in Hevea sp. x M. ulei pathosystem. Latent period had slight variation among clones. Lesion diameter had wide variation among clones and was a discriminating parameter for horizontal resistance and vertical resistance.