Responses of osmotic adjustment and seed yield of Brassica napus and B. juncea to soil water deficit at different growth stages
Qifu Ma A , Sharon R. Niknam A and David W. Turner A BA School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
B Corresponding author. Email: David.Turner@uwa.edu.au
Australian Journal of Agricultural Research 57(2) 221-226 https://doi.org/10.1071/AR04283
Submitted: 16 November 2004 Accepted: 15 September 2005 Published: 24 February 2006
Abstract
Canola (Brassica napus L.) is a major rotation crop but low yield has limited its adoption by farmers in the low-rainfall regions of southern Australia, where drought events can occur at any stage of crop development. We examined the effect of soil water deficit on osmotic adjustment and seed yield of canola and mustard (B. juncea L.) at the juvenile, elongation, anthesis, or seed-fill stage under glasshouse conditions and post-anthesis drought in the field. At the juvenile and elongation stages, leaves of both canola cv. Monty and mustard line 397-23-2-3-3 adjusted osmotically after exposure to water deficit. In comparison, only the mustard line expressed osmotic adjustment at anthesis and neither genotype adjusted at the seed-fill stage. A single drought event at the juvenile or elongation stage had little effect on growth and seed yield of either genotype, whereas water deficit at anthesis or seed-fill stage reduced seed yield of the canola cultivar by decreasing pod number, seeds per pod, and/or harvest index but largely did not affect the mustard line. In the field where rainfall diminished and plants were subjected to increasing water deficit during the reproductive stages, canola cv. Karoo and mustard line JN25 showed higher osmotic adjustment at anthesis and less yield reduction than the canola cv. Monty. This study suggests that yield sensitivity to water deficit was mainly due to its effect on concurrent formation of yield components, but could be modified by the physiological trait of osmotic adjustment.
Additional keywords: canola, mustard, drought, yield components, harvest index.
Acknowledgments
This project was funded by the Grains Research and Development Corporation, Australia. We thank Agriculture Western Australia for access to their facilities at the Merredin Dryland Research Institute, and are grateful to Mr Alan Meldrum for excellent support in the field. We acknowledge the helpful suggestions of a referee.
Chang, R (1981).
Diepenbrock W
(2000) Yield analysis of winter oilseed rape (Brassica napus L.): a review. Field Crops Research 67, 35–49.
| Crossref | GoogleScholarGoogle Scholar |
Dracup M,
Reader MA, Palta JA
(1998) Variation in yield of narrow-leafed lupin caused by terminal drought. Australian Journal of Agricultural Research 49, 799–810.
| Crossref | GoogleScholarGoogle Scholar |
French RJ, Ewing MA
(1989) Soil type influences the relative yields of different cereals and crop legumes in the Western Australian wheatbelt. Australian Journal of Experimental Agriculture 29, 829–835.
| Crossref | GoogleScholarGoogle Scholar |
Gammelvind LH,
Schjoerring JK,
Mogensen VO,
Jensen CR, Bock JGH
(1996) Photosynthesis in leaves and siliques of winter oilseed rape (Brassica napus L.). Plant and Soil 186, 227–236.
Leport L,
Turner NC,
French RJ,
Tennant D,
Thomson BD, Siddique KHM
(1998) Water relations, gas exchange and growth of cool-season grain legumes in a Mediterranean-type environment. European Journal of Agronomy 9, 295–303.
| Crossref | GoogleScholarGoogle Scholar |
Ludlow MM,
Santamaria JM, Fukai S
(1990) Contribution of osmotic adjustment to grain yield in Sorghum bicolor (L.) Moench under water-limited conditions. II. Water stress after anthesis. Australian Journal of Agricultural Research 41, 67–78.
| Crossref | GoogleScholarGoogle Scholar |
Ma Q,
Turner DW,
Levy D, Cowling W
(2004) Solute accumulation and osmotic adjustment in leaves of Brassica oilseeds in response to soil water deficit. Australian Journal of Agricultural Research 55, 939–945.
| Crossref | GoogleScholarGoogle Scholar |
Mengel, K ,
and
Kirkby, EA (1979).
Morgan JM
(1984) Osmoregulation and water stress in higher plants. Annual Review of Plant Physiology 35, 299–319.
| Crossref | GoogleScholarGoogle Scholar |
Morgan JM,
Rodriguez-Maribona B, Knights EJ
(1991) Adaptation to water-deficit in chickpea breeding lines by osmoregulation: relationship to grain-yields in the field. Field Crops Research 27, 61–70.
| Crossref | GoogleScholarGoogle Scholar |
Niknam SR,
Ma Q, Turner DW
(2003) Osmotic adjustment and seed yield of Brassica napus and B. juncea genotypes in a water-limited environment in south-western Australia. Australian Journal of Experimental Agriculture 43, 1127–1135.
| Crossref | GoogleScholarGoogle Scholar |
Richards RA, Thurling N
(1978) Variation between and within species of rapeseed (Brassica campestris and B. napus) in response to drought stress. I. Sensitivity at different stages of development. Australian Journal of Agricultural Research 29, 469–477.
| Crossref | GoogleScholarGoogle Scholar |
Santamaria JM,
Ludlow MM, Fukai S
(1990) Contribution of osmotic adjustment to grain yield in Sorghum bicolor (L.) Moench under water-limited conditions. I. Water stress before anthesis. Australian Journal of Agricultural Research 41, 51–65.
| Crossref | GoogleScholarGoogle Scholar |
Scholander PF,
Hammel HT,
Bradstreet ED, Hemmingsen EA
(1965) Sap pressure in vascular plants. Science 148, 339–346.
Subbarao GV,
Nam NH,
Chauhan YS, Johansen C
(2000) Osmotic adjustment, water relations and carbohydrate remobilization in pigeonpea under water deficits. Journal of Plant Physiology 157, 651–659.
Turner NC, Jones MM
(1980) Turgor maintenance by osmotic adjustment: a review and evaluation. ‘Adaptation of plants to water and high temperature stress’. (Eds NC Turner, PJ Kramer)
pp. 87–103. (Wiley Interscience: New York)
