Comparative assessment of the sensitivity of oilseed rape and wheat to limited water supply

Abstract

The drought-sensitivity of oilseed rape (OSR, Brassica napus cv. SW Landmark) was investigated, using the more widely studied crop species wheat (Triticum aestivum cv. Tybalt) as a benchmark. The water relations of OSR and wheat were compared in lysimeter and controlled environment experiments to test the hypothesis that the growth of OSR is restricted to a greater extent by soil drying than wheat and to determine whether the greater sensitivity results from differences in root or shoot traits. Plants were grown, with or without irrigation, in 1.2 m tall lysimeters packed with a sandy clay loam soil. The experiment was conducted in an open-sided glasshouse to encourage air flow and to resemble a field environment as far as possible; plant population densities were equivalent to commercial crops. Irrigated OSR (evapo)transpired more water than wheat (498 vs. 355 mm), but had a comparable water use efficiency (WUE; 4.1 vs. 4.4 g DW mm −1 H 2 O). Oilseed rape showed a greater reduction in above-ground growth (52% vs. 21%) and a smaller increase in WUE (27% vs. 45%) when water was withheld. Oilseed rape also responded to soil drying at a lower soil moisture deficit than wheat; transpiration rates fell below the potential of irrigated plants when plant available water remaining in the soil profile declined from 54 to 23% compared to 38 to 9% for wheat. The root hydraulic conductivity of young OSR plants, measured on root surface area basis, was about twice that of wheat, and was comparable on a root length basis. The results show that OSR was more sensitive to a restricted water supply than the benchmark species wheat and that the greater sensitivity resulted from differences in shoot, rather than root, characteristics. The root system of OSR was at least as efficient as wheat at extracting water from soil.

Root hydraulic properties: an exploration of their variability across scales

“…Actually, less than 10% of the reviewed studies included species corresponding to more than one PFT, and the hydraulic properties investigated there were unevenly distributed: while K rs and k root studies mostly focused on dicot and monocot crop species (Gallardo et al ., 1996; Bramley et al ., 2007; e.g. Hess et al ., 2015), broadleaf and needle trees were predominant in k x (or rather k x_cs ) studies (e.g. Maherali et al ., 2006; Domec et al ., 2010).…”

Long-Term Water Balance of Selected Field Crops in Different Agricultural Regions of the Czech Republic Using Fao-56 and Soil Hydrological Approaches

“…Daryanto et al [32] stated that wheat is less susceptible to drought due to effective soil water use owing to the dryland region origin. According to Hess et al [33], oilseed rape is more sensitive to a restricted water supply than wheat, which is stated to be associated with a lower WUE and a greater reduction in the yields following soil drying, even if the root system of oilseed rape is at least equally efficient as wheat in extracting water from soil. The lowest water stress of oilseed rape in our study could be explained by the lowest daily CWR (1.9-2.0 mm compared to 2.2-2.4 mm for winter wheat, 2.6-3.0 mm for maize and 2.8-3.1 mm for potatoes).…”

Evaluation of the Concentration-Response Relationship between Film Antitranspirant and Yield of Rapeseed (Brassica Napus L.) Under Drought

“…Rapeseed (Brassica napus L.) (also known as canola or oilseed rape) has become the third most essential crop globally for edible oil, fodder, and biofuel production after soybean and palm oil (FAOSTAT, 2020). Previous studies have reported that rapeseed can be highly affected by water stress during the flowering stage in terms of seed yield and yield components such as pod number and seed number per pod (Johnston et al, 2002;Istanbulluoglu et al, 2010;Hess et al, 2015). Ahmadi and Bahrani (2009) compared the effect of water stress imposed at three different growth stages (flowering, pod development and seed filling stage) on rapeseed.…”