[Effect of nitrogen and irrigation frequency on agronomic parameters and industrial quality of durum wheat]

The objective of this thesis was to evaluate the effect of nitrogen and irrigation frequency on agronomic and quality characters of five durum wheat genotypes (Triticum turgidum var durum), Chonta, Lican, Ucaro 1, Ambra and UC-17D. The characters evaluated were mature plant height, lodging, yield components, yield, test-weight, protein content and yellow berry percentage. The experimental design was a split-plot randomized complete block with four replications. Main plots were nitrogen fertilization: 0, 50, 100, 150, and 200 kg/ha applied as urea. The five durum wheat genotypes were the sub-plots. The experiment was conducted under two irrigation frequencies, every 8 and 12 days at Pirque. At the second location, Ovalle, the irrigation was not an experimental variable. Nitrogen had a significant effect on mature plant height and lodging; in both characters the highest response was found at the maximum nitrogen rate. Irrigation frequency, did not affect the character. Number of spikes per hectare and number of kernels per spike showed a consistent increase with a higher nitrogen rates. The frequency of irrigation had effects on the first and last characters, but had no significant effect on the number of kernels per spike. Irrigation induced a slight increase in test-weight which was not statistically significant. Nitrogen did not induce a definite response in this character. Increasing nitrogen levels induced higher yields up to 200 kg/ha of this nutrient. All genotypes yields significantly more under the irrigation frequency of 8 days. Nitrogen caused a significant increase in protein content, response that was also observed, when the cultivars were subjected to an irrigation frequency every 12 days. The lowest percentages of yellow berry were observed under the irrigation frequency of 12 days, as compared to the 8 day regime. Increasing nitrogen level induced a steady decrease in the expression of this character