Grain yiel progress and asociated physiological and agronomical traits in spring wheat (Triticum aestivum l.) in Çukurova during the last quarter of the 20th century

ABSTRACTPhD THESISGRAIN YIELD PROGRESS AND ASSOCIATED PHYSIOLOGICAL ANDAGRONOMICAL TRAITS IN SPRING WHEAT (Triticum aestivum L.) INÇUKUROVA DURING THE LAST QUARTER OF THE 20th CENTURYAyşe KUŞCUDEPARTMENT OF FIELD CROPSINSTITUTE OF NATURAL AND APPLIED SCIENCESUNIVERSITY OF ÇUKUROVASupervisor: Prof. Dr. Müjde KOÇYear: 2006, Pages: 225Jury: Prof. Dr. Müjde KOÇProf. Dr. İbrahim GENÇProf. Dr. Aydın AKKAYAProf. Dr. Ahmet Can ÜLGERProf. Dr. Mehmet KILINÇYield-progress in Çukurova and associated traits is not investigated very wellfor the last quarter of the 20th century. A chronological set of 16 cultivars realizedafter 1976 in Turkey was evaluated using two nitrogen doses in Çukurova/Turkey,during 2002/03 and 2003/04 wheat growing seasons.Doubling of nitrogen from 80 kg ha-1 to 160 kg ha-1 increased the grain yieldfrom 418 gm-2 to 544 gm-2 only in the second year. Average yield ranged from 464 gm-2 (Çukurova 86) to 596 g m-2 (Balattila and Yüreğir 89). With the realization of thesecond generation, Çukurova 86, the grain yield decreased about 0.74 % per yearcompared to that of Cumhuriyet 75. The rate increased up to 0.79 % per year until2000 (Balattila). Except for Pandas, yield progress stabilized in later years until2002. The average rate was 0.64 % or 3.22 g m-2 per year. Yield increases haveresulted in an increase in harvest index associated with reduced height and thedevelopment of more grains especially per ear.Significant cultivar differences were found in all the investigated agronomicaland physiological traits. The effect of nitrogen on these traits, and the response ofcultivar to nitrogen were not consistent. The trend of most of the physiological traitswas also not consistent. Only, flag leaf area decreased, while nitrogen harvest index,leaf area index, chlorophilla, chlorophillb and chlorophilla+b content increased withthe year of release.Keywords: Spring bread wheat, Grain yield progress, Nitrogen uptake and use, Leafarea index, Flag leaf physiological traitsII