Completed projects and reports

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Sugar Research Australia, Sugar Research Development Corporation and BSES reports from completed research projects and papers.

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Author: search.filters.author.Berding, NSubject: search.filters.subject.Breeding

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    Introgression of new genes from Saccharum officinarum
    (SRDC, 2004) Jackson, P; Piperidis, G; Aitken, K; Li, J; Morgan, T; Foreman, J; Hewitt, M; McIntyre, L; Berding, N
    Modern sugarcane cultivars are derived from two main ancestral species: Saccharum officinarum, which is the main source of high sucrose levels, and S. spontaneum. Only a small number of clones of either species have ever been incorporated into commercial cane breeding programs around the world. While incremental gains in cane yield and ratooning have been made by sugarcane breeders over the last 40 years sugarcane, there is concern that improvement in CCS has been very limited. One hypothesis for this is that because of the limited genetic base of sugarcane favourable alleles for high CCS in the breeding parent pool have already been fixed in current cultivars. If this hypothesis is correct then new genetic diversity will need to be introgressed from germplasm outside current breeding programs. Clones of S. officinarum, available in germplasm collections may provide a source of valuable high sucrose genes. However, introgression breeding using traditional breeding technologies is long term and high risk. The development of new DNA marker techniques has provided new opportunities for improving introgression breeding. These techniques provide a means to (i) characterise diversity within germplasm collections, (ii) identify genes or chromosomal regions, termed quantitative trait loci (QTL), from wild parents which cause positive or negative effects on important traits, which may then be selected for or against during breeding cycles. With this background in mind, this project had two concurrent aims: (i) To characterise a collection of S. officinarum clones for important phenotypic traits and for genetic diversity using DNA markers and identify a set of these for future breeding efforts; (ii) Using case study populations, to assess the value of using DNA marker assisted selection in introgression breeding in sugarcane. A range of candidate S. officinarum x commercial parent crosses were made at the start of the project using a random sample of S. officinarum clones not previously used in our breeding breeding program. From these a “case study” population was chosen for detailed investigation using DNA markers. Two of the progeny were subsequently chosen for “backcrossing” again to proven commercial parents to produce two other “backcross” populations. Concurrently, the collection of 282 S. officinarum clones in the Australian collection was also characterised using DNA markers, along with 147 parent clones in the Australian core breeding program. A subset of 158 S. officinarum clones, recently imported from overseas, was also evaluated in a field trial for CCS and cane yield across a plant and two ratoon crops.
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    Effect of far-red radiation on flowering of Saccharum spp. hybrids : SRDC Final report BS1S
    (1990) Berding, N; Moore, PH
    Many tropical sugarcane clones (Saccharum spp. hybrids) are unavailable for hybridization because of poor flowering. Methods are required to improve the flowering of such clones. This study was conducted to determine whether far-red radiation (> 700 nm) at end-of day would improve flowering. Three treatments in a photoperiod facility (PPF) were compared to an external control (EC) under natural photoperiod. A basic treatment known as modified Florida (MF) was used in all PPF treatments and served as the internal control. This was altered to provide a far-red (FR) treatment, by addition of either 5 or 10 min of far-red radiation at end-of-day, and a day interrupt (Dr) treatment, by imposition of 2 hr of darkness in mid afternoon. Percent flowering as harvested panicles was 21.0, 24.2, 24.6, and 9.5 for FR, Dr, MF, and EC, respectively. Total flowering was 23.4, 28.9, 27.0, and 10.7, respectively. The PPF treatments did not differ significantly for either measure. All were highly significantly greater than EC. The far-red treatments did not differ for harvested panicles. Treatments differed significantly for time of flowering. The flowering sequence was EC, MF, FR, and then DI. There were significant differences among clones in all treatments for emergence day, initiation day, elapsed days, and pollen test. Correlations among these measures were varied, with some being significant. Far red at end-of-day neither stimulated nor inhibited flowering in the PPF treatments. The FR and Dr treatments delayed emergence of flowering.
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