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Gibberellin (GA) insensitive dwarfing genes Rht-B1b and Rht-D1b that are responsible for the ‘Green Revolution’ have been remarkably successful in wheat improvement globally. However, these alleles result in shorter coleoptiles and reduced vigour and hence poor establishment and growth in some environments. Rht18, on the other hand, is a GA sensitive, dominant gene with potential to overcome some of the early growth limitations associated with Rht-B1b and Rht-D1b. We assessed progeny from both a biparental and backcross population that contained tall, single-dwarf and double-dwarf lines, to determine whether Rht18 differs from Rht-D1b and hence verifying its value in wheat improvement. Progeny with Rht18 had an almost identical height to lines with Rht-D1b, and both were about 26% shorter than the tall lines with the double dwarf 13% shorter again. However, coleoptile length of Rht18 was 42% longer than Rht-D1b. We detected no differences in time to terminal spikelet, anthesis and few differences in stem or spike growth. Both dwarfing genes diverted more dry matter to the spike than tall lines from prior to heading. No differences were detected between Rht18 and Rht-D1b that could prevent the adoption of Rht18 in wheat breeding to overcome some of the limitations associated with the ‘Green Revolution’ genes.

Item Type:	Refereed Article
Keywords:	early growth, stem internodes, assimilate competition, carbohydrate remobilisation
Research Division:	Agricultural, Veterinary and Food Sciences
Research Group:	Crop and pasture production
Research Field:	Agronomy
Objective Division:	Plant Production and Plant Primary Products
Objective Group:	Grains and seeds
Objective Field:	Wheat
UTAS Author:	Tang, T (Mr Ting Tang)
UTAS Author:	Botwright Acuna, T (Associate Professor Tina Acuna)
ID Code:	141397
Year Published:	2020
Deposited By:	Agriculture and Food Systems
Deposited On:	2020-10-19
Last Modified:	2020-12-02
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