Browsing by Author "Jackson, PA"

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Evaluation and re-structuring of regional selection programs to maximise efficiency and speed of cultivar release
(2002) Chapman, SC; Rattey, A; Jackson, PA
Continual delivery of new cultivars is required to maintain resistance to existing and new pests and diseases, and to provide constant improvement in crop productivity, quality and profitability for an internationally competitive sugar industry. Sugarcane breeding comprises two major activities: genetic variation is created by crossing parents (selected on historical performance of their progeny in the case of proven parents, or performance for heritable traits in trials in the case of new parents), and the best clones for release are selected through a multi-stage selection process that involves progressively more intensive testing of fewer clones over several years in multiple sites. In Australia, the geographic variation in climate and other conditions in the different regions, the difficulties of moving sugar cane planting material, and differences between regions for some diseases (e.g. the Fiji disease line between the Central and Burdekin regions) had resulted in six cultivar crossing and selection programs, each targeting different regions: North (inc. Atherton Tableland), Herbert, Burdekin, Central, South and northern NSW. The small Ord irrigation area is serviced via testing and selection of elite clones from all of these regional trials. Currently crosses are made in each of four specific regions based on performance of parents (in trials or via progeny performance) in that region. Clones from crosses are initially chosen from small plots in one site per region. In further selection, breeders conduct multi-row plot trials across sites and seasons, with intensive testing within regions, and later exchange of the most promising clones between regions. At the start of this project, there was no basic information on whether clones generated directly from crosses generally perform consistently relative to each other between regions, or whether many clones exhibit specific adaptation to regional environments. This information, and quantifying the relative sizes of genotype, genotype x region interaction, and genotype x within-region interaction variances, in genetic populations generated in breeding programs, is basic information needed for designing an optimal selection system that collectively targets all regions.
Genotype X environment interaction and selection of sugarcane families for the Burdekin River irrigation area : SRDC final report BS57S
(1995) McRae, TA; Jackson, PA
The arable lands being developed for sugarcane production in the Burdekin River Irrigation Area (BRIA) are on markedly different soil types and, as a consequence, may present environmental challenges different to those influencing sugarcane production on the more established alluvial soils of the Burdekin delta and levee areas.
Improved selection systems and data analysis in sugarcane breeding programs : SRDC final report BSS250
(2006) Wei, X; Jackson, PA
Overcoming constraints to high yield and CCS in large and lodged cane crops
(2001) Chapman, SC; Jackson, PA; Lawn, RJ
Past research indicates that large sugarcane crops (that usually also happen to be lodged) experience a slowdown in growth during winter, well before harvest (Muchow et al. 1996). The project examined factors affecting the growth of crops in both the dry (irrigated) and wet tropics and aimed to interpret and explain the effects of the identified factors on net growth and death processes as well as on the stalk and sucker dynamics, cane yield and CCS. Treatments included installation of bamboo scaffolding to prevent crop lodging, and a late ratooning of the crop so that a physiologically young crop would be growing into the winter ripening period. Experiments were conducted over two seasons (1997-1998 & 1998-1999) in commercial fields in areas where large crops may experience substantial lodging under different environmental conditions (Burdekin and Tully). Four or five sequential harvests were taken to determine if and when growth slowdown occurred and to separate the effects of crop age, season and lodging. By installing scaffolding to prevent lodging, we eliminated the growth ‘slowdown’ in three experiments to confirm that lodging and stalk death is part of the explanation. In both the wet and dry (irrigated) tropics, lodging of sugarcane significantly decreased both cane yield and fresh commercial cane sugar content (CCS). Prevention of lodging increased fresh cane yield by 11 - 15 %, CCS by 3 - 12 % and sugar yield by 15 - 35 % at the final harvest in August/September. The rate of increase in CCS in lodged cane was reduced following lodging, although CCS recovered by harvest to be similar to that of erect cane. While death of stalks was confirmed as a major component of the effect of lodging there was also a reduced weight and sugar content of live stalks. Dead and rat damaged stalks had CCS levels that were regularly less than 50% of sound live stalks. In the dry tropics, where cane is irrigated and grows under high radiation, sugar yield was 40 t/ha with scaffolding installed. The increased yield (compared to 35 t/ha in lodged cane) was due to both the survival of an extra 0.8 stalks/m2 and increased accumulation of sugar in live stalks. These experimental results have been published in two conference papers and in an upcoming issue of the Australian Journal of Agricultural Research (early 2003).