Applied phenomics and genomics for improving barley yellow dwarf resistance in winter wheat

Barley yellow dwarf (BYD) is one of the major viral diseases of cereals. Phenotyping BYD in wheat is extremely challenging due to similarities to other biotic and abiotic stresses. Breeding for resistance is additionally challenging as the wheat primary germplasm pool lacks genetic resistance, with most of the few resistance genes named to date originating from a wild relative species. The objectives of this study were to, i) evaluate the use of high-throughput phenotyping (HTP) from unmanned aerial systems to improve BYD assessment and selection, ii) identify genomic regions associated with BYD resistance, and iii) evaluate genomic prediction models ability to predict BYD resistance. Up to 107 wheat lines were phenotyped during each of five field seasons under both insecticide treated and untreated plots. Across all seasons, BYD severity was lower with the insecticide treatment and plant height (PTHTM) and grain yield (GY) showed increased values relative to untreated entries. Only 9.2% of the lines were positive for the presence of the translocated segment carrying resistance gene Bdv2 on chromosome 7DL. Despite the low frequency, this region was identified through association mapping. Furthermore, we mapped a potentially novel genomic region for resistance on chromosome 5AS. Given the variable heritability of the trait (0.211 0.806), we obtained relatively good predictive ability for BYD severity ranging between 0.06 0.26. Including Bdv2 on the predictive model had a large effect for predicting BYD but almost no effect for PTHTM and GY. This study was the first attempt to characterize BYD using field-HTP and apply GS to predict the disease severity. These methods have the potential to improve BYD characterization and identifying new sources of resistance will be crucial for delivering BYD resistant germplasm.

Phytochemical and Pharmacological Evaluation of Yellow and Green Variety of Cocus nucifera Water

Coconut water widely consumed as a health drink by people around the world. This led to an urge to study various properties of Cocus nucifera. We evaluated anti oxidant and phyto chemical constituents of two variety of coconut the yellow and green variety. Phytochemical assays showed the presence of terpinoids, alkaloids, resin, sugars, steroids, glycosides and tannins in both the dwarfs but yellow variety showed more amount of photochemical constituents. In both the variety of coconut water antioxidants were found. In the assay of DPPH, scavenging of nitric oxide assay and scavenging of hydrogen peroxide the presence of antioxidants were proved against the standard ascorbic acid. Results found yellow variety to be more potent antioxidant. All assays proved yellow dwarf was healthier than green dwarfs with more health benefits and medicinal properties.

Advances in understanding the biology and epidemiology of barley yellow dwarf virus (BYDV)

A tri-trophic network of domesticated grasses (host), various aphids (vector) and barley yellow dwarf virus (pathogen) species has been spread by humans from Eurasia to the rest of the world. Understanding how climate, natural and agricultural landscapes challenge pathogens, vectors, and their natural enemies and shape their dynamics is the key to managing this pathosystem. This chapter provides an overview of this complex system and its evolution. The chapter includes a case study of biological control of aphids causing wheat BYDV in Brazil. The current challenge is to create tools that integrate knowledge of this complex pathosystem and facilitate monitoring and decision making for rational management to reduce the burden of disease.

Resistance breeding in barley against Barley yellow dwarf virus (BYDV): avoiding negative impacts on anatomy and physiology

Barley yellow dwarf (BYD) is one of the most widespread and damaging viral diseases of grasses and cereal crops worldwide. Due to an increasing risk of food losses e.g. in barley by Barley yellow dwarf virus (BYDV) as a consequence of climate change, associated by a strong demand to decrease the use of chemical insecticides, breeding for BYDV resistance is of prime importance today. This chapter describes the negative impact of BYDV on barley on multiple levels (anatomy, physiology and agronomic traits). It also demonstrates the benefits of BYDV resistance regarding a reduction in yield losses but also a decreased spread of BYDV in the field due to effects on the tritrophic interaction of virus, vector and plant. Until now, several genes and QTL are known that mediate tolerance or resistance against BYDV, respectively. The combination of genomic tools and phenotyping is the basis for the identification of these genes and recent developments facilitate to enhance this process.

Virus Diseases of Cereal and Oilseed Crops in Australia: Current Position and Future Challenges

This review summarizes research on virus diseases of cereals and oilseeds in Australia since the 1950s. All viruses known to infect the diverse range of cereal and oilseed crops grown in the continent’s temperate, Mediterranean, subtropical and tropical cropping regions are included. Viruses that occur commonly and have potential to cause the greatest seed yield and quality losses are described in detail, focusing on their biology, epidemiology and management. These are: barley yellow dwarf virus, cereal yellow dwarf virus and wheat streak mosaic virus in wheat, barley, oats, triticale and rye; Johnsongrass mosaic virus in sorghum, maize, sweet corn and pearl millet; turnip yellows virus and turnip mosaic virus in canola and Indian mustard; tobacco streak virus in sunflower; and cotton bunchy top virus in cotton. The currently less important viruses covered number nine infecting nine cereal crops and 14 infecting eight oilseed crops (none recorded for rice or linseed). Brief background information on the scope of the Australian cereal and oilseed industries, virus epidemiology and management and yield loss quantification is provided. Major future threats to managing virus diseases effectively include damaging viruses and virus vector species spreading from elsewhere, the increasing spectrum of insecticide resistance in insect and mite vectors, resistance-breaking virus strains, changes in epidemiology, virus and vectors impacts arising from climate instability and extreme weather events, and insufficient industry awareness of virus diseases. The pressing need for more resources to focus on addressing these threats is emphasized and recommendations over future research priorities provided.

Comparative Biology of Coconut Leaf Beetle (Clb) Brontispa longissimi (Gestro) (Coleoptera: Chrysomelidae) on Selected Coconut Varieties

Comparative biology and development study of B. longissima Gestro was conducted using different coconut varieties namely: Baybay tall (BAYT) green, Baybay tall (BAYT) brown, Malayan Red dwarf (MRD), Malayan Yellow dwarf (MYD), Albuera dwarf (ALD), and Tacunan dwarf (TACD) varieties was investigated in the laboratory. The duration of the developmental period of B. longissimi was influenced by the different coconut varieties used as host plant. Duration from egg laying to hatching of eggs of B. longissima on tall varieties ranged from 3 to 5 days, while on dwarf varieties it took 4 to 5 days. In all varieties, Brontispa beetles underwent 5–6 instars. In addition, it was observed that the fifth and sixth instars took a longer time period compared to other instars. The total mean developmental period of Brontispa on BAYT (green and brown) was shorter in days compared to all dwarf varieties except to ALD. The results generally showed that BAYT (green and brown) seemed to be a preferred variety. There was considerably higher larvae mortality in dwarf variety like MRD (40%) than those reared in the BAYT green and brown (22.21%, 19.12%), respectively. Beetles reared on BAYT (brown) also had the highest fecundity which was statistically different from the rest of the varieties. In addition, results showed that adults reared in both BAYT (green and brown) had the highest longevity observed compared to other varieties

Cytoplasmic Matrix and Viroplasms Inclusions in the Presence of Gold Nanoparticles (AuNPs)

Cellular ultrastructure micrographs revealed striking changes resulting from the Barley Yellow Dwarf Virus (BYDV-PAV) infection in Electron microscopy. In the cytoplasm, the Gold nanoparticles (AuNPs) may bind with different cytoplasmic organelles and interfere with the treated site’s metabolic processes. The micrographs of the treated plant leave with AuNPs showing; Endosomes, amorphous bodies, slender filaments fibers, myelin bodies with a high concentration of virus particles, and Gold Nanoparticles distributed in a circulated shape in the cytoplasm with virus particles.