NITROGEN-FERTILIZATION OF DURUM-WHEAT CULTIVARS IN THE RAIN-FED AREA OF MOROCCO - BIOMASS, YIELD, AND QUALITY CONSIDERATIONS

Nitrogen is the dominant fertilizer element required for cereals in Mo rocco. While fertilization is less common in the semi-arid (250-450 mm ) cereal belt than at higher rainfall zones, the benefits in terms of yield increases and economics are potentially important. However, rese arch has been focused mainly on bread wheat (Triticum aestivum L), not withstanding the importance of durum wheat (T. Turgidum var durum L). This on-farm trial in a shallow soil (Petrocalcic Palexeroll) in the d ryland Chaouia area of south-central Morocco evaluated the impact of N (0, 30, 60, 90, 120 kg N/ha) in five durum cultivars (Kyperounda or 2 777, Marzak, Massa, Cocorit, Karim). Data were influenced by both N an d cultivar, with no interaction between them. Nitrogen significantly i ncreased biomass and grain yields up to 90 kg/ha; it had little effect on either grain N concentration, except at the highest level (120 kg/ ha), or kernel weight, but tended to decrease the percentage of ''yell ow berry''. Yields were significantly higher for Kyperounda, Marzak, a nd Karim than either Cocorit or Massa. Grain N and kernel weight were little influenced by cultivar, but the incidence of ''yellow berry'' v aried with the cultivar. While recognizing cultivar differences, the s tudy highlights the role of N for yield and quality components of duru m wheat.