Mango Breeding Support

The Mango Breeding Support project provided technical, research and development support to the Queensland-based, Australian Mango Breeding Program to develop and evaluate breeding systems and technologies that improve mango breeding efficiency. Adoption of efficient breeding support technologies will allow breeders to identify genes for desirable plant and fruit traits in parent varieties and incorporate those genes into new hybrid varieties more efficiently and rapidly. The project compared traditional hand pollination methods with DNA marker assisted selection (MAS) open-pollinated methods to identify paternity and found both systems had advantages. Marker assisted paternity identification was not practical in all cases and relied on a greater range of technical skills and resources being available to the breeder. It is expected that MAS will become even more efficient when markers are available for production and quality traits in addition to parental identification. Breeding for anthracnose resistance in mango is in its infancy. This project has identified several accessions in related Mangifera species with potential tolerance to postharvest anthracnose and tested the compatibility of these related species with the common mango and if the tolerance is transferable. The project investigated ways of determining a trees postharvest fruit disease resistance status in seedlings to avoid the up to 6 year wait for trees to crop. Identification of genes and gene markers for plant development, stress response, fruit colour and flavour development was another goal of this project. Twenty five new expressed sequence tag (EST) derived single sequence repeat (SSR) DNA markers were identified and tested across a diverse range of germplasm. These markers were shown to be useful in determining genetic relationships, exploring potential pedigrees and estimating the genetic background of cultivated accessions of M. indica. They are the first reported EST-SSR markers suitable to cross-amplify in five wild Mangifera species. The technologies that have been shown to be more efficient have been incorporated in to the Australian Mango Breeding Project. Other technologies being researched that are not yet fully developed to the stage where they can be adopted in a working breeding program are being progressed in other related research projects

Field and laboratory evaluation of fungicides for the control of Phytophthora fruit rot of papaya in far north Queensland, Australia

Results from the first of two artificially inoculated field experiments showed foliar applications of copper hydroxide (Blue Shield Copper) at 600 g a.i./100 L−1 (0% infected fruit), copper hydroxide + metalaxyl-M (Ridomil Gold Plus.) at 877.5 g a.i./100 L−1 (0.27%), metiram + pyraclostrobin (Aero) at 720 g a.i./100 L−1 (0.51%), chlorothalonil (Bravo WeatherStik) at 994 g a.i./100 L−1 (0.63%) and cuprous oxide (Nordox 750 WG) at 990 g a.i./100 L−1 (0.8%) of water significantly reduced the percentage of infected fruit compared to potassium phosphonate (Agri-Fos 600) at 1200 g a.i./100 L−1 (8.22%), dimethomorph (Acrobat) at 108 g a.i./100 L−1 (11.18%) and the untreated control (16%). Results from the second experiment showed fruit sprayed with copper hydroxide (Champ Dry Prill) at 300 (2.0% infected fruit), 375 (0.4%) and 450 g a.i./100 L−1 (0.6%) and metiram + pyraclostrobin (Aero) at 360 (2.8%), 480 (0.6%) and 600 g a.i./100 L−1 of water (1.0%) significantly reduced the percentage of infected fruit compared to the untreated control (19.4%). Foliar sprays of copper hydroxide at 375 g a.i./100 L−1 in rotation with chlorothalonil at 994 g a.i./100 L−1 every two weeks is now recommended to growers for controlling Phytophthora fruit rot of papaya

Mango Breeding Support

The Mango Breeding Support project provided technical, research and development support to the Queensland-based, Australian Mango Breeding Program to develop and evaluate breeding systems and technologies that improve mango breeding efficiency. Adoption of efficient breeding support technologies will allow breeders to identify genes for desirable plant and fruit traits in parent varieties and incorporate those genes into new hybrid varieties more efficiently and rapidly. The project compared traditional hand pollination methods with DNA marker assisted selection (MAS) open-pollinated methods to identify paternity and found both systems had advantages. Marker assisted paternity identification was not practical in all cases and relied on a greater range of technical skills and resources being available to the breeder. It is expected that MAS will become even more efficient when markers are available for production and quality traits in addition to parental identification. Breeding for anthracnose resistance in mango is in its infancy. This project has identified several accessions in related Mangifera species with potential tolerance to postharvest anthracnose and tested the compatibility of these related species with the common mango and if the tolerance is transferable. The project investigated ways of determining a trees postharvest fruit disease resistance status in seedlings to avoid the up to 6 year wait for trees to crop. Identification of genes and gene markers for plant development, stress response, fruit colour and flavour development was another goal of this project. Twenty five new expressed sequence tag (EST) derived single sequence repeat (SSR) DNA markers were identified and tested across a diverse range of germplasm. These markers were shown to be useful in determining genetic relationships, exploring potential pedigrees and estimating the genetic background of cultivated accessions of M. indica. They are the first reported EST-SSR markers suitable to cross-amplify in five wild Mangifera species. The technologies that have been shown to be more efficient have been incorporated in to the Australian Mango Breeding Project. Other technologies being researched that are not yet fully developed to the stage where they can be adopted in a working breeding program are being progressed in other related research projects

Basil Downy Mildew management options – is it seedborne?

Basil downy mildew (Peronospora belbahrii) was identified for the first time in Australia in 2017. Since the first report, the fungal organism spread rapidly with incidences reported in all states other than Tasmania and Western Australia. There have been significant impacts on both field and glasshouse grown crops of basil with growers unable to manage the level of infection, this led to a shortened growing season and a reduced number of picking cycles. The purpose of the research study was to examine whether seed was the primary source of disease spread in Australia and to identify potential management strategies for the disease The research results showed no evidence to suggest that the commercial basil seed used was infested with basil downy mildew. However, the overseas literature states that the level of seed detection can be as low as (0.03%), therefore a higher sampling frequency would be required to confidently conclude that seed is or isn’t infected. The project delivered on a number of aspects: • The successful detection of the basil downy mildew (BDM) organism in seed (known field infection) using molecular technology. • A technique developed to inoculate plants artificially which could be used to determine cultivar susceptibility to the disease and to screen products for disease management (fungicides/biologicals). • Molecular assays tested and implemented that can detect the BDM organism in pure form, infected foliage and in seed. • Provision of advice in relation to chemical permit applications, which has led to an additional five fungicides permitted for use to manage BDM

Evaluation of the efficacy of commercial disinfectants against Fusarium oxysporum f. sp. cubense Race 1 and Tropical Race 4 propagules

Panama disease caused by Fusarium oxysporum f. sp. cubense (Foc) has devastated banana production worldwide. This work aimed to determine effective disinfectants against two races of Foc, race 1 and tropical race 4 (TR4), for implementation with on-farm biosecurity procedures against this disease following the outbreak of TR4 in North Queensland in 2015. A total of 32 commercial disinfectants were screened and their activity was assessed after ≤ 30 sec, 5 min, 30 min and 24 hr of contact with a Foc suspension containing 105/ml chlamydospores without and with soil added (0.05 g/ml). Of the disinfectants tested, the quaternary ammonium compounds containing ≥ 10% active ingredient were found to be the most effective against both Foc races. These products, when used at a 1:100 dilution, completely inhibited the survival of all Foc propagules across all the contact times regardless of the absence or presence of soil. The bioflavonoids product EvoTech 213 and bleach (10% sodium hypochlorite) used at a 1:10 dilution also eliminated all Foc propagules across all the contact times. None of the detergent-based or miscellaneous products tested were completely effective against both Foc races even used at a 1:10 dilution. Soil decreases the efficacy of disinfectants and therefore must be removed from contaminated items before treatments are applied

Evaluation of the efficacy of commercial disinfectants against Fusarium oxysporum f. sp. cubense Race 1 and Tropical Race 4 propagules

Panama disease caused by Fusarium oxysporum f. sp. cubense (Foc) has devastated banana production worldwide. This work aimed to determine effective disinfectants against two races of Foc, race 1 and tropical race 4 (TR4), for implementation with on-farm biosecurity procedures against this disease following the outbreak of TR4 in North Queensland in 2015. A total of 32 commercial disinfectants were screened and their activity was assessed after ≤ 30 sec, 5 min, 30 min and 24 hr of contact with a Foc suspension containing 105/ml chlamydospores without and with soil added (0.05 g/ml). Of the disinfectants tested, the quaternary ammonium compounds containing ≥ 10% active ingredient were found to be the most effective against both Foc races. These products, when used at a 1:100 dilution, completely inhibited the survival of all Foc propagules across all the contact times regardless of the absence or presence of soil. The bioflavonoids product EvoTech 213 and bleach (10% sodium hypochlorite) used at a 1:10 dilution also eliminated all Foc propagules across all the contact times. None of the detergent-based or miscellaneous products tested were completely effective against both Foc races even used at a 1:10 dilution. Soil decreases the efficacy of disinfectants and therefore must be removed from contaminated items before treatments are applied

Mango germplasm screening for the identification of sources of tolerance to anthracnose

Colletotrichum species are one of the most common causes of postharvest fruit rot in mango in Australia, particularly in the tropical region of north Queensland, and can result in significant losses if not managed. The research aims were to identify sources of anthracnose tolerance and to determine if host material other than fruit could improve or fast track the screening process and result in improved breeding efficiency. Access to the Australian National Mango Genebank (ANMG) collection enabled fruit screening of more than 100 Mangifera indica cultivars or Mangifera species for tolerance to anthracnose by artificial inoculation with Colletotrichum asianum over a period of 14 years. Mean lesion diameters were compared with those on a known susceptible M. indica cultivar Kensington Pride (KP) and a tolerant M. laurina cultivar Lombok. Inoculation of leaf discs and entire leaves was evaluated in the laboratory and the field as alternative assays for tolerance to anthracnose and was assessed by presence/absence of disease. Screening of fruit has shown that anthracnose tolerance within the mango germplasm is highly variable and needs to be assessed over multiple years. None of the alternative laboratory bioassays provided consistent or reliable data. The in-field artificial inoculation of immature leaf flush was successful but was not deemed suitable for adoption due to practical restraints. While resistance to anthracnose in fruit has not yet been identified, some cultivars and Mangifera spp. showed promise for inclusion as parents in future breeding programs

Microbial sharing between pediatric patients and therapy dogs during hospital animal-assisted intervention programs

Microbial sharing between humans and animals has been demonstrated in a variety of settings. However, the extent of microbial sharing that occurs within the healthcare setting during animal-assisted intervention programs is unknown. Understanding microbial transmission between patients and therapy dogs can provide important insights into potential health benefits for patients, in addition to addressing concerns regarding potential pathogen transmission that limits program utilization. This study evaluated for potential microbial sharing between pediatric patients and therapy dogs and tested whether patient-dog contact level and a dog decolonization protocol modified this sharing. Patients, therapy dogs, and the hospital environment were sampled before and after every group therapy session and samples underwent 16S rRNA sequencing to characterize microbial communities. Both patients and dogs experienced changes in the relative abundance and overall diversity of their nasal microbiome, suggesting that the exchange of microorganisms had occurred. Increased contact was associated with greater sharing between patients and therapy dogs, as well as between patients. A topical chlorhexidine-based dog decolonization was associated with decreased microbial sharing between therapy dogs and patients but did not significantly affect sharing between patients. These data suggest that the therapy dog is both a potential source of and a vehicle for the transfer of microorganisms to patients but not necessarily the only source. The relative contribution of other potential sources (e.g., other patients, the hospital environment) should be further explored to determine their relative importance

Field evaluation of strobilurins, triazoles and acibenzolar to control Sigatoka disease in Australia

Strobilurin fungicides (trifloxystrobin, azoxystrobin, and pyraclostrobin), a plant activator (acibenzolar), and triazole fungicides (JAU 6475 and epoxiconazole) were evaluated in three field experiments in northern Queensland, Australia, for control of Sigatoka disease (caused by Mycosphaerella musicola). In all experiments, the strobilurins used, alone or in conjunction with mancozeb and acibenzolar, were as effective or better than the industry standards mancozeb and propiconazole. Acibenzolar used in conjunction with mancozeb significantly improved the control of Sigatoka disease compared to mancozeb alone. The triazoles, epoxiconazole and JAU 6476 were as effective as the industry standard propiconazole. In 2004, trifloxystrobin, pyraclostrobin and epoxiconazole were registered for control of Sigatoka diseases on banana