The Australian mango breeding project

The Australian mango industry is currently dominated by Kensington Pride which comprises some 80 per cent of all plantings. This is in contrast to other countries with modern export industries such as South Africa, Israel and Mexico, which are based on three to five cultivars. A joint venture between Agriculture Western Australia, the Queensland Department of Primary Industries (DPI), the Northern Territory Department of Primary Industries and Fisheries (DPIF) and the CSIRO commenced six years ago to generate a wide range of promising new mango hybrids that can meet both domestic and export market requirements. There has been considerable success to date

Σύνθεση ιοντικών υγρών και βαθέων ευτηκτικών διαλυτών και εφαρμογή τους στο διαχωρισμό του αζεοτροπικού μίγματος αιθανόλης/νερού

Productivity in temperate tree crops such as apple has been lifted several-fold by research focusing on optimising a combination of canopy components including light relations, vigour control, tree architecture and crop load. This paper outlines the research behind the Small Tree-High Productivity Initiative (STHPI), which is focused on improving productivity of mango, avocado and macadamia. Preliminary results from work we are undertaking for each of the above canopy components in mango will be outlined. A rootstock screening trial to identify vigour-managing, high-productivity rootstocks is being undertaken, and we present a comparison of the best-performing low-medium vigour rootstock varieties compared with control 'Kensington Pride' (KP) rootstock at 6 months old. Comparisons between 'Keitt', 'NMBP 1243' and 'Calypso' scion cultivars with regard to tree diameter, height and canopy growth at different orchard densities and training systems will also be presented. Preliminary results from an orchard light-relations study indicate that mango yields continued to increase with light interception up to 50%, and reached a maximum of 20-30 t ha at 68% light interception in KP trees approximately 25 years old. In a crop load trial, inflorescence thinning in a 'Calypso' orchard did not significantly reduce yields when up to 90% of inflorescences were removed, but did when 95% of inflorescences were removed, as trees were unable to compensate by adjusting fruit set, size and yield. Inflorescence thinning beyond 80% increased the number of fruit set per panicle, and thinning up to and including 90% of inflorescences increased fruit weight from 340 g to >400 g per fruit. This project is still in its initial stages; however, early indications suggest there may be opportunities to improve early orchard yields through optimising light interception in an orchard's life, potentially through the use of higher densities, and that rootstocks and tree training methods, once identified, may help in the management of vigour. It is also hoped to obtain a better understanding of how crop load influences the balance between vegetative growth, flowering, fruiting, alternate bearing and fruit quality

The Physics of Star Cluster Formation and Evolution

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00689-4.Star clusters form in dense, hierarchically collapsing gas clouds. Bulk kinetic energy is transformed to turbulence with stars forming from cores fed by filaments. In the most compact regions, stellar feedback is least effective in removing the gas and stars may form very efficiently. These are also the regions where, in high-mass clusters, ejecta from some kind of high-mass stars are effectively captured during the formation phase of some of the low mass stars and effectively channeled into the latter to form multiple populations. Star formation epochs in star clusters are generally set by gas flows that determine the abundance of gas in the cluster. We argue that there is likely only one star formation epoch after which clusters remain essentially clear of gas by cluster winds. Collisional dynamics is important in this phase leading to core collapse, expansion and eventual dispersion of every cluster. We review recent developments in the field with a focus on theoretical work.Peer reviewe

Evaluation of potting media for rapid growth of mango nursery plants

In Pakistan, mango nurseries are currently located in the traditional way, in the soil under trees in mango orchards. This method is responsible for the young plants being contaminated with many of the diseases present on mature trees. To produce clean and healthy plants, Pakistani mango nurseries must change their practices to isolate the nurseries from orchards and use clean potting media. In this study, a range of ingredients with fine and coarse texture were combined into 12 different media and tested for plant survival (%), plant height (cm), stem diameter (cm) and the physical and chemical properties of each potting medium. The potting medium that achieved maximum seedling survival (94%) contained bagasse (70%), silt (25%) and coconut fiber (5%) (by volume). This medium also achieved maximum plant height (60 cm) and maximum stem girth (1.2 cm) of seedlings after 1 year. The physical and chemical properties of this leading potting medium were 38% water-holding capacity (WHC), 13% air-filled porosity (AFP), 1300 µS cm-1 electrical conductivity (EC) and pH 7.8 after 4 months of seed germination. When farmyard manure (FYM) was used at any level (20 to 50%) with any other potting medium component, it caused seedling death within 3-4 months of seed germination. This research was conducted under the ACIAR-funded Pakistan-Australia Agriculture Sector Linkages Program (ASLP). The result of this research has led to the first recommendation of an evaluated potting medium for use in the mango nursery sector in Pakistan

The Australian mango breeding project

The Australian mango industry is currently dominated by Kensington Pride which comprises some 80 per cent of all plantings. This is in contrast to other countries with modern export industries such as South Africa, Israel and Mexico, which are based on three to five cultivars. A joint venture between Agriculture Western Australia, the Queensland Department of Primary Industries (DPI), the Northern Territory Department of Primary Industries and Fisheries (DPIF) and the CSIRO commenced six years ago to generate a wide range of promising new mango hybrids that can meet both domestic and export market requirements. There has been considerable success to date

Benefits of intensive production systems in mango

Mangoes are grown in over 100 countries throughout the tropical and subtropical world with a total production of over 42×10 t of fruit sold in both local and export markets. In tropical regions, mangos are typically large, vigorous, low yielding trees with very low production and harvest efficiencies. In Queensland, Australia, a collaborative research project between the Department of Agriculture and Fisheries, the University of Queensland and Hort Innovation Australia has been developing high density, intensive production orchard systems in tropical and subtropical tree fruits. The project is investigating and documenting the relationships between the key drivers of productivity orchards. In mango, the aim of this research is to radically redesign orchard systems, increasing their production efficiency and profitability. Experimental intensification using higher planting densities and single leader training of canopies has led to early gains in productivity (~47 t ha-1 in year 4). This paper outlines some of the key relationships that are underpinning these early productivity gains in areas such as tree architecture and canopy volume, canopy training, canopy light interception and light distribution

Management of mango decline using thiophanate methyl and plant activators through a macro infusion system

Mango decline disease has become a major cause of tree losses of about 7-10% in all mango growing areas of Pakistan. This study evaluated the effectiveness of plant activators used in conjunction with the fungicide thiophanate methyl in managing mango decline disease. The study was conducted in the Multan district using trees rated as 1-2 on a decline severity scale and displaying symptoms of gummosis, bark splitting, canker formation, and leaf drooping. Experimental treatments included three plant activators viz. Bion, Planofix, and Root king in conjunction with or without thiophanate methyl, delivered through a macro infusion system. This was the first time a macro infusion system had been used in Pakistan. The injection system delivered the fungicide/activator mixture into the tree trunk under pressure through a series of holes bored into the xylem tissue. Tree disease symptoms were recorded fortnightly to assess the treatment efficacy. After three months, thiophanate methyl, in combination with Bion, was found to be the most effective treatment with trees displaying no apparent disease symptoms. When thiophanate methyl was used alone, or in combination with Root king and Planofix, the symptoms of bark splitting and gummosis persisted

INHERITANCE OF FRUIT CHARACTERS IN HYBRID MANGOES PRODUCED THROUGH CONTROLLED POLLINATION

Mango fruit quality attributes have been evaluated in hybrids produced by the Australian National Mango Breeding Program. Since its inception in 1994 the program has generated more than 1800 hybrids from 33 parental combinations using controlled pollination methods. Characterisation of the fruit was carried out by assessing 24 internal and external attributes and an estimate was made of the heritabilities of characters for which the data were either quantitative or were scored on an evenly ordered hedonic scale. Analysis of the data indicated that many important fruit quality aspects such as fruit weight, fruit shape, ground skin colour, fruit width and pulp depth have high heritabilities, and can therefore be readily selected in a breeding programme. For non-ordered traits scored in discrete categories (blush colour, bloom, lenticel colour, embryo type and flavour), an estimate was made of data consistency from multiple scores for individual hybrids at different times and locations. A relatively high consistency value was recorded for fruit flavour, and in combinations involving Kensington Pride, between 24% and 47% of hybrids were scored as having Kensington Pride flavour. The embryo type of hybrids was also recorded and the data are discussed in the context of polyembrony being controlled by a single dominant gene

Inheritance of fruit characters in hybrid mangoes produced through controlled pollination

Mango fruit quality attributes have been evaluated in hybrids produced by the Australian National Mango Breeding Program. Since its inception in 1994 the program has generated more than 1800 hybrids from 33 parental combinations using controlled pollination methods. Characterisation of the fruit was carried out by assessing 24 internal and external attributes and an estimate was made of the heritabilities of characters for which the data were either quantitative or were scored on an evenly ordered hedonic scale. Analysis of the data indicated that many important fruit quality aspects such as fruit weight, fruit shape, ground skin colour, fruit width and pulp depth have high heritabilities, and can therefore be readily selected in a breeding programme. For non-ordered traits scored in discrete categories (blush colour, bloom, lenticel colour, embryo type and flavour), an estimate was made of data consistency from multiple scores for individual hybrids at different times and locations. A relatively high consistency value was recorded for fruit flavour, and in combinations involving Kensington Pride, between 24% and 47% of hybrids were scored as having Kensington Pride flavour. The embryo type of hybrids was also recorded and the data are discussed in the context of polyembrony being controlled by a single dominant gene