New mango hybrids from Australia

The Australian National Mango Breeding Program has been breeding mangoes since 1994. In recent years, evaluation of the elite selection have identified three high performing hybrids, NMBP1243, NMBP1201 and NMBP4069, which are in the process of commercial release. These hybrids all have 'Kensington Pride' as their paternal parent and are characterised by improved fruit colour and tree productivity over 'Kensington Pride'. NMBP1243 is noted for its early season production, and NMBP1201 and NMBP4046 for their firm fruit. The hybrids were produced using hand pollination breeding and selection techniques. The breeding program is ongoing with the current hybridisation program being supported by a multidiscipline approach, that includes marker assisted screening, disease screening, postharvest evaluation and a genomics gene discovery program.

Commercial-scale Alternaria brown spot resistance screening as the first step in breeding new mandarins for Australia

Rapid screening tests and an appreciation of the simple genetic control of Alternaria brown spot (ABS) susceptibility have existed for many years, and yet the application of this knowledge to commercial-scale breeding programs has been limited. Detached leaf assays were first demonstrated more than 40 years ago and reliable data suggesting a single gene determining susceptibility has been emerging for at least 20 years. However it is only recently that the requirement for genetic resistance in new hybrids has become a priority, following increased disease prevalence in Australian mandarin production areas previously considered too dry for the pathogen. Almost all of the high-fruit-quality parents developed so far by the Queensland-based breeding program are susceptible to ABS necessitating the screening of their progeny to avoid commercialisation of susceptible hybrids. This is done effectively and efficiently by spraying 3-6 month old hybrid seedlings with a spore suspension derived from a toxin-producing field isolate of Alternaria alternate, then incubating these seedlings in a cool room at 25°C and high humidity for 5 days. Susceptible seedlings show clear disease symptoms and are discarded. Analysis of observed and expected segregation ratios loosely support the hypothesis for a single dominant gene for susceptibility, but do not rule out the possibility of alternative genetic models. After implementing the routine screening for ABS resistance for three seasons we now have more than 20,000 hybrids growing in field progeny blocks that have been screened for resistance to the ABS disease.