Molecular characterization of Caulerpa racemosa (Caulerpales, Chlorophyta) from Indonesia based on the Plastid tufA Gene

The green seaweed Caulerpa racemosa is a seaweed of high prospect that is being given emphasis by the Indonesian government. However, C. racemosa in Indonesia may include multiple species level-entity exhibiting morphological overlap and require molecular analysis for species identification. Molecular documentation of species richness of indigenous populations of C. racemosa is essential to underpin cultivar development and conservation of the species to avoid overharvesting. The present study aimed to determine the genetic diversity of C. racemosa and document the haplotype network of the specimens from four different locations (Bintan Island, Jepara, Takalar and Osi Island) using the chloroplast tufA gene. Twenty individuals from four areas were collected and amplified with the chloroplast-encoded gene tufA for species identification against publicly available data. The identification of C. racemosa based on the tufA gene showed that the species found in four locations were C. cylindracea (previously C. racemosa var. cylindracea), C. macra (previously C. racemosa var. macra), C. racemosa, and C. oligophylla (previously C. racemosa var. lamourouxii). This study records the existence of C. cylindracea in Takalar and Jepara, Indonesia for the first time. The most diverse C. racemosa species was in Osi Island, where the exploitation of this seaweed is very low. In contrast, the lowest number of C. racemosa varieties were found in Takalar, where exploitation is very high. There were only minor light variations of Caulerpa species in the tufA gene in four different sites with only four haplotypes found, and each haplotype corresponded to another species.

Computational Discovery of a miRNA and its Putative Target Genes in Ziziphus Jujuba using Genome-wide Expressed Sequence Tags

Background Ziziphus jujuba is an important fruit crop which is increasingly becoming popular among consumers due to its medicinal properties. Increasing worldwide demand for the fruit poses new challenges to the industry which includes the need for accelerated cultivar development of jujubes. To embark on cultivar development with improved traits such as high yield and disease resistance, molecular and conventional breeding, and genetic engineering become imperative. But inadequate trait-enhancing alleles or gene pleiotropism limit the direct use of several identified genes. To overcome these issues, microRNAs (miRNAs) can be utilized in breeding of jujubes as genetic modulators to fine-tune the regulation of gene expression, thus the discovery of miRNAs becomes important. Methods and results In this study using a computational approach, we identified one potential miRNA (zju-miR-215-3p) from 2904 expressed sequence tags. The miRNA showed down regulation of five target proteins (AP-2 complex subunit alpha, C2H2-type domain-containing protein, sentrin-specific protease 1, hydrolase_4 domain-containing protein and putative alpha-ketoglutarate-dependent dioxygenase) and their suppression appears to be helpful to the plant to overcome stress conditions. Conclusion The miRNA identified in this study is associated with five potential target proteins, most of which are implicated in metabolic and developmental processes associated with plant growth and reproduction. Future studies are necessary to validate the miRNA by RNA sequencing and to confirm the molecular functions of the down regulations of target proteins.

Advances in Breeding of Peach, Plum and Apricot

Research on the expression of fruit specific genes may allow breeders in the future to selectively manipulate through gene transfer in certain aspects of fruit development/quality in their advanced breeding lines thus reducing the time necessary for cultivar development. This would be particularly useful in breeding programmes, hybridizing standard cultivars with exotic germplasm of low fruit quality. The use of exotic germplasm will be important for the expansion of the peach germplasm base and the development of stress resistant cultivars. More immediate results of research on fruit specific gene expression will provide a better understanding of fruit development and quality. It is required to learn how the differences at the gene level correlate with quality characteristics. With the continued cooperation of fruit biochemists it is expected to obtain a better definition of fruit quality and a better understanding of fruit biochemistry. The potential will exit to generate a range of “anti-sense mutants” i.e. transgenic plants expressing anti-sense gene contstructs that reduce or nullify the effects of the normal gene. The phenotypes of these mutants could help to define the biochemistry, genetics and quality of peach fruit. The development of efficient regeneration and transformation system in peach will be useful not only for the modification of fruit characteristics, but also for the transfer and manipulation of genes affecting stress resistance and other economically important characters.

Survey of Sugarcane Yellow Leaf Virus in the Canal Point Breeding and Cultivar Development Program

Sugarcane yellow leaf virus (SCYLV), a Polerovirus in the family Luteoviridea, causes yellow leaf disease (YLD). Yield losses from YLD have been reported from several countries in both symptomatic and asymptomatic sugarcane cultivars. The breeding nursery at Canal Point (CP) in 2016 and primary and secondary seed increases in the CP cultivar development program at grower’s farm from 2015 to 2019 were surveyed for SCYLV infection by the tissue-blot immunoassay using polyclonal antibodies raised against SCYLV. More than 32% of varieties in the CP breeding nursery were infected with SCYLV in 2016. The SCYLV data of primary and secondary seedcane increases from 2015 to 2019 showed that out of 54 varieties screened at different locations, 12 had no SCYLV-positive plants, 24 had less than 5%, 5 had 6% to 12%, and 13 had 20% to 75% of the plants infected with SCYLV. The SCYLV screenings in varieties in the primary and secondary seed increase plantings provide growers an opportunity to acquire virus-free clean seedcane by apical meristem propagation to minimize the spread of the SCYLV and avoid yield losses.

Evolution of Fusarium Head Blight Management in Wheat: Scientific Perspectives on Biological Control Agents and Crop Genotypes Protocooperation

Over the past century, the economically devastating Fusarium Head Blight (FHB) disease has persistently ravished small grain cereal crops worldwide. Annually, losses globally are in the billions of United States dollars (USD), with common bread wheat and durum wheat accounting for a major portion of these losses. Since the unforgettable FHB epidemics of the 1990s and early 2000s in North America, different management strategies have been employed to treat this disease. However, even with some of the best practices including chemical fungicides and innovative breeding technological advances that have given rise to a spectrum of moderately resistant cultivars, FHB still remains an obstinate problem in cereal farms globally. This is in part due to several constraints such as the Fusarium complex of species and the struggle to develop and employ methods that can effectively combat more than one pathogenic line or species simultaneously. This review highlights the last 100 years of major FHB epidemics in the US and Canada, as well as the evolution of different management strategies, and recent progress in resistance and cultivar development. It also takes a look at protocooperation between specific biocontrol agents and cereal genotypes as a promising tool for combatting FHB.

A Systematic Narration of Some Key Concepts and Procedures in Plant Breeding

The goal of a plant breeding program is to develop new cultivars of a crop kind with improved yield and quality for a target region and end-use. Improved yield across locations and years means better adaptation to the climatic, soil, and management conditions in the target region. Improved or maintained quality renders and adds value to the improved yield. Both yield and quality must be considered simultaneously, which constitutes the greatest challenge to successful cultivar development. Cultivar development consists of two stages: the development of a promising breeding population and the selection of the best genotypes out of it. A complete breeder's equation was presented to cover both stages, which consists of three key parameters for a trait of interest: the population mean (μ), the population variability (σG), and the achieved heritability (h2 or H), under the multi-location, multi-year framework. Population development is to maximize μσG and progeny selection is to improve H. Approaches to improve H include identifying and utilizing repeatable genotype by environment interaction (GE) through mega-environment analysis, accommodating unrepeatable GE through adequate testing, and reducing experimental error via replication and spatial analysis. Related concepts and procedures were critically reviewed, including GGE (genotypic main effect plus genotype by environment interaction) biplot analysis, GGE + GGL (genotypic main effect plus genotype by location interaction) biplot analysis, LG (location-grouping) biplot analysis, stability analysis, spatial analysis, adequate testing, and optimum replication. Selection on multiple traits includes independent culling and index selection, for the latter GYT (genotype by yield*trait) biplot analysis was recommended. Genomic selection may provide an alternative and potentially more effective approach in all these aspects. Efforts were made to organize and comment on these concepts and procedures in a systematic manner.

A High Throughput Method for Generating Dihaploids from Tetraploid Potato

There is a worldwide effort to increase the efficiency of potato (Solanum tuberosum L.) cultivar development by using inbred diploid breeding lines. This activity is impeded by the cost and effort required to produce dihaploids from cultivated tetraploid potatoes. We developed a high throughput dihaploid production method based on the 60-year-old method of Peloquin and Hougas. Red Norland inflorescences from commercial fields were transferred to greenhouses. As buds developed, pollen from the dihaploid inducer IVP 101 was applied systematically to thousands of stigmas per trial. Berries were harvested 21 days after pollination. Seeds of putative dihaploids lacking a seed spot marker were retained and ploidy was confirmed using flow cytometry. We recovered 23 dihaploids from 21,651 pollinations. This is a promising method for systematically carrying out thousands of pollinations since the cost of field-grown flowers is dramatically less than that of greenhouse-grown flowers.

Potential Threat of Bruchids on Soybean Production in Sub-Saharan Africa

Soybean production in sub-Saharan Africa (SSA) has been increasing in recent years in part due to the efforts of several national and international research agencies, including the Soybean Innovation Laboratory (SIL). SIL’s mission to increase utilization and production of soybean in SSA has led to several facets of research including cultivar development to increase yield through the Pan-African Soybean Variety Trials (PATs). Several abiotic and biotic stresses can decrease yield, including pathogens and pests that attack seed. While evaluating seed lots from 32 PAT locations, we identified bruchids and/or bruchid-damaged seed in nine locations in four countries (Cameroon, Malawi, Mozambique, and Rwanda). The most severe damage and infestation was recorded in Bwanje, Malawi, with 28 of the 40 seed lots infested. Seed damage ranged from 0.6 to 100% among the 28 infested seed lots. Adult bruchids discovered at the Bwanje location were identified as Callosobruchus chinensis, or the Chinese bruchid. No adults were found in other locations. Bruchids are a destructive storage pest of legumes, and monitoring the different species attacking soybean will help researchers and producers understand the potential threat of bruchids to soybean production in SSA as well as help implement the best management practices.

Genetic diversity in Colocasia esculenta and Xanthosoma mafaffa in Togo, West Africa

Taro and new cocoyam are root and leaf crops commonly grown in tropical to warm temperate regions. In Togo, they are neglected and underutilised. Here we report the genetic diversity of 26 accessions of taro and 101 accessions of new cocoyam. Analysis of simple sequence repeats revealed low polymorphic information content of 0.43 and 0.25 in taro and new cocoyam, respectively. PCA scatterplots and Neighbour Joining dendrograms based on the SSR data clustered accessions into groups that more-or-less correspond to morphological diversity in both species. AMOVA within and between morphological groups revealed greater variances within groups than between. This indicates weak genetic differentiation between morphological groups, particularly for taro. Genetic diversity was greater among taro cultivars. Taro has a longer history of introduction and dispersal in Africa, and has had more opportunity for multiple introduction and local cultivar development. Different strategies are suggested for future development of these crops in Togo and Africa. For taro, further studies of existing diversity and recent experimental introduction, has spread widely in Africa with little genetic diversity. For this crop, international collaboration is needed to clarify taxonomy, and to introduced further cultivars for evaluation under local conditions in Africa.