. 2010. Fertilizer response for hybrid and open-pollinated canola and economic optimal nutrient levels. Can. J. Plant Sci. 90: 305Á310. Hybrid (HY) canola (Brassica napus L.) produces a higher seed yield than open-pollinated (OP) canola. While it is expected higher-yielding HY canola may require higher total available nutrients, especially nitrogen (N), the evidence is not conclusive. This study used canola yield data from several site-years and fertility experiments to determine whether HY and OP canola types require different rates of total available N (TAN) and total available phosphorus (TAP). The yield response of the two canola genotypes to TAP was the same, but for TAN the yield response was greater for HY canola. The quadratic yield response results were confirmed using three plateau equations. Optimal TAN for HY canola was higher than for OP canola. Soil test laboratories and producers growing HY canola need to modify N fertility for HY canola, compared with OP canola for which most of the current N fertilizer recommendations were developed. . Le rendement des deux ge´notypes re´agit de la meˆme fac¸on au PTD, mais celui du canola hybride re´agit davantage a`l'ATD. La re´action quadratique du rendement a e´te´confirme´e graˆce a`trois e´quations plateau. La concentration optimale d'ATD est plus e´leve´e pour le canola hybride que pour le canola a`pollinisation libre. Les laboratoires qui analysent le sol et les producteurs de canola hybride doivent adapter les amendements N pour ce type de culture, la plupart des recommandations actuelles en matie`re de fertilisation reposant sur la culture du canola a`pollinisation libre.

Th e high cost of hybrid (HY) canola (Brassica napus L.) seed has some producers considering F 2 generation hybrid farm-saved seed (HY-FSS), or open-pollinated (OP) varieties (both certifi ed and farm-saved seed). Th e net return (NR) of diff erent varieties, genetic backgrounds, seeding rates, seed treatments, and seed sizing was evaluated from three experiments over eight site-years of fi eld data from western Canada. One set of experiments included variety, genetic background and seeding rate, while another included seed treatment, genetic background and seed sizing. Th e experiments used randomized complete block designs. Th e NR accounted for yield, green seed price discount, seed costs, and other production costs. Analysis of variance indicated certifi ed F 1 hybrid seed (HYC) was more profi table than HY-FSS (15%, P = 0.0057) and OP (22%, P = 0.0001). With delayed weed control, NR was lower for HYC and not statistically diff erent than HY-FSS. Higher seeding rates and seed sizing for HY-FSS did not increase NR compared to HYC. Th e fi ndings of this study support the use of HYC canola seed, especially at high canola prices. Canola producers will not increase their NR by using HY-FSS or OP seed to reduce their seed cost because the lost value of production exceeds the higher cost of HYC seed.

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