Previous PageTable Of ContentsNext Page

Morphological and physiological characters associated with higher grain yields of modern wheats

K.H.M. Siddique and M.W. Perry

Western Australian Department of Agriculture, Baron-Hay Court, South Perth W.A. 6151

In the Mediterranean type environment of Western Australia, a study of historically significant wheat cultivars (1) suggested that genetic change had increased grain yield by about 6 kg ha-1 year-1. Little is known about the morphological and physiological characters associated with past yield improvement. A current project aims to identify such changes and examines the potential for further yield improvement.

Methods

Field experiments were conducted over three seasons (1986 to 1988) at Perth, Wongan Hills and Merredin, Western Australia. The cultivars represented a chronological sequence of economically significant wheat cultivars from the 1860s to the 1980s. The experiments were sown as early as possible (end of May). Plot size was 2.16 m wide (12 rows, 18 cm apart) x 40 m long. Detailed measurements were made on phenology; organ initiation, growth and survival; dry matter partitioning; water use and plant water relations.

Results and discussion

Modern cultivars differed from the old, in developing faster, flowering earlier, forming fewer erect leaves and having a reduced phyllochron interval. Tillering was reduced (with greater tiller survival), but light interception increased and biomass was greater in modern compared to old cultivars. Increased ear:stem ratio at the terminal spikelet stage and at anthesis, more florets/spikelet, greater floret survival, and a longer grain growth period with a shorter lag phase also characterised modern cultivars. These changes were expressed as greatly increased grain number ear-1 (and m-2) and greater harvest index (1, 2, 3, 4 and 5).

Gamenya, released in 1960, was a 'watershed' cultivar in Western Australia and clearly demarcates the end of cultivars based on Farrer's material. Changes from Gamenya to recent cultivars such as Gutha (1982) and the semi-dwarf Kulin (1986) are small, but continue the trends towards earliness, increased ear:stem ratio and greater floret survival. Improvement in total biomass represents the alternate means of yield improvement and this deserves greater attention.

1. Perry, M.W. and D'Antuono, M.F. (1989). Aust. J. Agric. Res. 40. (in press).

2. Kirby, E.J.M., Siddique, K.H.M., Perry, M.W., Kaesehagen, D. And Stern, W.R. (1989). Field Crops Res. 20 (in press).

3. Siddique, K.H.M., Belford, R.K., Perry, M.W. and Tennant, D. (1989). Aust. J. Agric. Res. 40 (in press).

4. Siddique, K.H.M., Kirby, E.J.M. and Perry, M.W. (1989). Field Crops Res. 21 (in press).

5. Loss, S.P., Kirby, E.J.M., Siddique, K.H.M. and Perry, M.W. (1989). Field Crops Res. 21 (in press).

Previous PageTop Of PageNext Page

...

Search Site