Investigation of N Deficiency in Cherry Trees Using Visible and Near-Infrared Spectra Part of the Spectrum in Field Condition

This objective of the study was to develop a model for the determination of N deficiency in cherry trees using a combination of visible near infrared methods and spectro-radiometric measurement.In our experimental design,cherry seedlings were grown under various N deficiency conditions in nutrient-controlled containers.The reflectance values of plant leaves were measured using a spectro-radiometer.Plant leaves samples were simultaneously collected.Their nutrient contents were determined in the laboratory.Afterwards,we performed a statistical comparison of the reflectance values.Sample analysis results established the significant wavelengths.Moreover,we received accurate regression models for predicting N deficiency in cherry leaves that were grown in nutrient solutions.Next,we verified the model validity by measuring the reflectance of the leaves collected from cherry orchards at various locations using a spectroradiometer.Nutrient deficiencies were calculated using the developed model,and then,the predicted and measured data were compared to evaluate model validity.From these results,we determined the wavelengths that yielded the most accurate results for N prediction,selected from the blue and green regions of the spectrum.We established that for N prediction in cherry trees,the simplest model can be created using 560and 570nm wavelengths.However,the evaluated model can be applicable only under certain conditions.We concluded that in order to develop aprediction method with sufficient application capacity,as well as the ability to assess nutritional and physiological characteristics,the ecology condition of the plant should be properly considered based on the model.

Genetic gains in wheat in Turkey: Winter wheat for dryland conditions

Wheat breeders in Turkey have been developing new varieties since the 1920 s, but few studies have evaluated the rates of genetic improvement. This study determined wheat genetic gains by evaluating 22 winter/facultative varieties released for rainfed conditions between 1931 and2006. The study was conducted at three locations in Turkey during 2008-2012, with a total of 21 test sites. The experimental design was a randomized complete block with four replicates in2008 and 2009 and three replicates in 2010-2012. Regression analysis was conducted to determine genetic progress over time. Mean yield across all 21 locations was 3.34 t ha^(-1) but varied from 1.11 ha^(-1) to 6.02 t ha^(-1) and was highly affected by moisture stress. Annual genetic gain was 0.50% compared to Ak-702, or 0.30% compared to the first modern landmark varieties. The genetic gains in drought-affected sites were 0.75% compared to Ak-702 and0.66% compared to the landmark varieties. Modem varieties had both improved yield potential and tolerance to moisture stress. Rht genes and rye translocations were largely absent in the varieties studied. The number of spikes per unit area decreased by 10% over the study period,but grains spike^(-1) and 1000-kemel weight increased by 10%. There were no significant increases in harvest index, grain size, or spike fertility, and no significant decrease in quality over time. Future use of Rht genes and rye translocations in breeding programs may increase yield under rainfed conditions.