Pan, X., Caldwell, C. D., Falk, K. C. and Lada, R. 2012. The effect of cultivar, seeding rate and applied nitrogen on Brassica carinata seed yield and quality in contrasting environments. Can. J. Plant Sci. 92: 961–971. The unremitting growth of oilseed demand makes it necessary to explore alternative oilseed crops to meet this requirement. This study evaluated the effects of genotype, seeding rate and nitrogen (N) supply on the seed yield and quality of oilseed Brassica carinata A. Braun in three contrasting environments (Truro, NS, Harrington, PE and Saskatoon, SK). Useful genetic variation in agronomic and seed quality characteristics was found among these 10 B. carinata genotypes and genotype selection requires location specific recommendation. Line 050488EM had consistently good yield in both Nova Scotia and Prince Edward Island, while line 070768EM displayed better yield stability across 2 yr in Saskatchewan. Because of the high degree of compensatory ability to low plant population, maximum seed yield of B. carinata can be achieved over the range from 34 to 114 plants m−2. No significant difference in oil and protein content of seed due to seeding rates was observed. The linear increase in seed and oil yield with increased N rate up to 150 kg ha−1 indicates that B. carinata is highly responsive to applied N. Increases in N supply resulted in a decrease in oil content and a corresponding increase in protein content in all experiments. In summary, the findings of this study provide convincing evidence of the agronomic adaptation of B. carinata to all three locations.

Effects of water and nitrogen (N) supply on growth and photosynthetic response of B. carinata were examined in this study. Plant growth and related characteristics varied significantly in response to the availability of water and nitrogen. B. carinata maximized the utilization efficiency of the most limiting resources by developing physiological adaptations, such as changes in root and leaf development. The utilization of water and N was tightly linked with the availability of each resource. Instantaneous water-use efficiency (WUE) was always greater in plants with high-N nutrition [50, 100, and 150 kg(N) ha −1 ] than in the low-N-treated plants [0 kg(N) ha −1 ] in all watering treatments. Instantaneous N-use efficiency (PNUE) decreased significantly with increasing water stress in all N treatments. Seed yield is significantly related to PNUE (p>0.05) but not WUE (p<0.05). The positive relationship between leaf net photosynthetic rate (P N ) and seed yield suggests that P N can be used as an important tool for selection of new strains with high seed yield.

Water and nitrogen (N) deficiency are two major constraints limiting the yield and quality of many oilseed crops worldwide. This study was designed to assess the response of Camelina sativa (L.) Crantz to the availability of N and water resources on photosynthesis and yield parameters. All the measured variables, which included plant height, root and shoot dry matter, root:shoot ratio, xylem pressure potential (XPP), yield components, photosynthetic parameters, and instantaneous water-use efficiency (WUE) were remarkably influenced by water and nitrogen supply. Net photosynthetic rate (P N ) and yield components were significantly decreased more by water deficit than by N deficiency. XPP, stomatal conductance (g s ), and intercellular CO 2 concentration (C i ) decreased substantially as the water deficit increased irrespective of the level of N application. WUE at the high N supply [100 and 150 kg(N) ha -1 ] dropped in a large degree as the increased water deficit due to a larger decrease in P N than transpiration rate (E). The results of this study suggest that the regulative capacity of N supply on photosynthetic and plant growth response is significantly affected by soil water status and C. sativa is more sensitive to water deficit than N supply.Additional key words: instantaneous water-use efficiency; net photosynthesis; nitrogen supply; seed yield; soil water status; transpiration rate. ---The unremitting growth of oilseed demand makes it necessary to explore new oilseed crops to meet this requirement. C. sativa, with many positive agronomic attributes such as apparent low-input requirements, adaptation to semiarid regions, tolerance of low-fertility and high disease and insect resistance (Schuster and Friedt 1998, Zubr 1997), has great potential to be grown across Canada. In order to introduce a new oilseed crop, it is necessary to determine the resource requirements of this crop.Accurate assessment of resource-use efficiency is crucial to an understanding of how to optimize growth and yield through an improved management. The relationship among applied N rate, photosynthesis, and growth has been well documented (Field and Mooney 1986, Cechin andFumis 2004). Many previous studies have addressed the response of stomatal behavior, leaf water status and photosynthesis to soil water status (McVetty et al. 1989, Reddy et al. 2003. However, information on the interactive effect of nitrogen and water on C. sativa growth and photosynthetic response is limited. Hence, this study was initiated to determine the photosynthetic and yield responses of C. sativa to various N and moisture regimes. The main objectives of the study were to (1) determine the interactive effects of N and moisture regimes on growth and yield components and (2) evaluate the effect of applied N and water on P N , E, and WUE.In a controlled environment study, C. sativa cv. Calena (provided by the Nova Scotia Crop Development Institute) was used to study the effect of different N rates [0, 50, 100, and 150 kg(N) ha -1 , which corresponded to 0, 0...