Varieties, plant breeding and release
Permanent URI for this collectionhttp://elibrary2.sugarresearch.com.au/handle/11079/13841
Research outcomes: Comprehensive and efficient variety breeding, selection and release programs responding to yield expectations, environmental constraints, resource scarcity and regional preferences. Faster varietal adoption using advanced methods for bulking, distribution and planting.
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Item Exploiting introgression for the development of productive and regionally adapted varieties for NSW : final report 2013/022(Sugar Research Australia Limited, 2020) Parfitt, RC; Beattie, RNThis project aimed to explore sugar cane variety improvement opportunities available through introgression in relation to 2-year cropping, temperate cane growing conditions of NSW and frosting. It provided an opportunity to review the NSW selection program that has been operating since early 2000.Item Prospects for a genetic solution to the management of ratoon stunting disease : ASSCT peer-reviewed paper(ASSCT, 2021) Bhuiyan, SA; Eglinton, J; Magarey, RCRatoon stunting disease (RSD,) caused by a bacterium (Leifsonia xyli subsp. xyli), is one of the most important diseases of sugarcane in Australia. RSD is an inconspicuous and highly infectious disease and can spread unnoticed causing significant yield loss across entire regions and industries. Developing varieties with resistance to RSD has been proposed at different times as a possible solution. This paper provides a review of the resistance status of the sugarcane germplasm, the effective range in reactions to the disease, and the efficacy of current practices used for RSD management. Examination of the Australian germplasm and historical resistance records show that material with effective RSD resistance has never been identified. Published literature has occasionally suggested that there are resistant varieties/clones, but these putative sources of resistance have failed to demonstrate commercially-effective disease control. Currently, there are no validated sources of resistance available to be used as parents in the breeding program. Evidence from overseas and Australia demonstrates that RSD can be successfully managed through disease-free planting material and farm hygiene. A genetic solution for RSD may only be considered if an effective source of resistance can be identified and validated.Item Genomic organisation of sugarcane cultivars revealed by chromosome-specific oligonucleotide probes : ASSCT peer-reviewed paper(ASSCT, 2021) Piperidis, N; Piperidis, G; D’Hont, ASugarcane (Saccharum spp.) is probably the crop with the most complex genome. Modern cultivars (2n=100-120) are derived from interspecific hybridization between the noble cane S. officinarum (2n=80) and the wild cane S. spontaneum (2n=40-128). We investigated the genome organization of important sugarcane cultivars and their parental species using chromosomespecific probes combined with genomic in situ hybridization (GISH). This allowed the genomic and genetic characterisation of Australian sugarcane cultivars and one of the major contributing parental clones, Mandalay. The S. spontaneum clone Mandalay follows the classical organization of S. spontaneum clones with x=8 with a major discrepancy related to an extra six chromosomes compared to the previously reported 2n=96 for Mandalay’s clone. Our previous results reported the rearrangements between the S. officinarum (x=10) and S. spontaneum (x=8) chromosomes, with a most likely scenario of a two-step process leading to x= 9 and then x=8, where each step involved three chromosomes that were rearranged into two. Further polyploidization led to the wide geographical dispersion of S. spontaneum clones with x= 8. In modern cultivars, the 13-20% of the S. spontaneum contribution originated from cytotypes with x=8. Modern cultivars have mainly 12 copies of each of the first four basic chromosomes and a more variable number for those basic chromosomes whose structure differs between the two parental species. These new insights and cytogenetic tools substantially improve our understanding of the extreme level of complexity of modern sugarcane cultivar genomes and could lead to guiding breeding strategies in the development of new improved varieties for the Australian industry.Item Seed-based in vitro propagation to accelerate variety development : ASSCT peer-reviewed paper(ASSCT, 2021) Zhao, L; Bolton, C; Piperidis, G; Eglinton, JTo shorten the current lengthy selection process in sugarcane breeding and to accelerate genetic gain, Sugar Research Australia is implementing a range of novel breeding strategies and selection tactics. One strategy is to rapidly evaluate the progeny of elite crosses in replicated trials without passing through the traditional Stage 1 trials. However, insufficient planting material hinders its adoption. A seed-based in vitro propagation system has been developed for sugarcane in which sodium hypochlorite (bleach) and plant preservative mixture (PPMTM) were used in the sterilisation of seeds and seedlings, as well as in the treatment of infected seedlings. The system had been successfully implemented to propagate over 1000 clones of the elite cross Q208A x CP74-2005, for a Stage 2 selection trial. The new system, a first for sugarcane, is more cost efficient, providing three times the number of clones as in the seedling-based micropropagation system with the same input of resources. This innovation will shorten the selection cycle of proven elite crosses by up to 3 years, accelerating the delivery of new varieties.