This field study was performed at the Agricultural Research Farm (Ghazala location), Faculty of Agriculture, Zagazig University., Egypt during 2002/2003 and 2003/2004 seasons to evaluate the effect of seeding rate (expressed herein as seed number, being 800, 1200 and 1600 seeds/m2) and N fertilization levels (20, 40 and 60 kgN/fad) on the yield and some certain characters of the two flax genotypes (local cultivar Giza 7 and Imported genotype Elise). In each trial, split-split plot design of three replicates was employed, with 2 genotypes as main plots, the three seeding rates as sub-plots and the three N levels as sub-sub plots. The experimental unit was 6 m2 with dimensions of 2x3 m.
The results showed significant cultivar behaviour, since Giza 7 cultivar was markedly distinguished on its similar Elise one in each of : stem diameter, number of basal and apical branches / plant, straw yield/fad, capsule and seed numbers/plant, seed index, seed yield/fad, seed oil percentage and oil yield/fad. On the other hand, Elise genotype was significantly superior as for : plant height, technical stem length, fibre% and fibre yield/fad. Such trend was greatly valid in both seasons and over them.
The three numbers of seeds/m2 gave considerable response in all flax traits studied, since planting 800 seeds/m2 gave greater mean values respecting : stem diameter, number of basal and apical branches/plant, capsule and seed numbers / plant, seed index and seed oil content. Moreover, planting 1600 seeds / m2 possessed greater excess in each of : plant height, technical stem length, fibre% and at last the final yields/fad of straw, fibre, seed and oil when compared with both 800 and 1200 seeding rates. This phenomenon was completely true in both trials and across them as well.
Nitrogen fertilization levels exerted noticeable variations in all tested flax traits, since the 20 kg N dose was most effective in raising both fibre% and seed oil content. Likewise, the 60 kg N level attained the greatest mean records regarding plant height, technical stem length, stem diameter, number of basal and apical branches/plant, straw and fibre yields/fad, capsule and seed numbers / plant, seed index and both seed and oil yields/unit area. Such N levels trend was fairly manifested in both seasons and their pooled data as well.
Planting 1600 seeds/m2 interacted meaningly with 60 kg N/fad to produce pronounced increments as for : plant height, fibre% and fibre yield/fad (respecting Elise genotype), number of basal branches/plant as well as straw, seed and oil yields/fad (in case of Giza 7 cultivar). In other score, the final yields/fad from straw, fibre, seed and oil were markedly maximized by considering the 1600 seeding rate along with 60 kg N level/fad under the circumstances of this investigation.