Relationships between wheat yield, yield components and physico-chemical properties of soil under rain-fed conditions

This research was conducted to study and classify the physico-chemicalproperties of soil, yield components of wheat and to determine the significance ofthese parameters on the grain yield formation. In this research, seven statisticalmethods consisting of simple correlation analysis (SCA), multiple linear regression(MLR), stepwise regression (SR), factor analysis (FA), principal componentanalysis (PCA), cluster analysis (CA) and path analysis (PA) have beeninvestigated. The physico-chemical properties of soil, different morphological traitsand wheat yield have been obtained from a field with 250×300 meter dimensionlocated in Bajgah (with silty clay loam soil) that consisted of 30 samples. Amongstatistical analysis performed, MLR has provided more acceptable results. In thismethod, among the examined characteristics, five traits i.e., the number of stemswithout spikes per plant, biological yield, harvest index, soil soluble potassium andsoil available phosphorus, examined 98.3% of the variations of the yield (P<0.05).Lack of soil nitrogen effect on yield is due to drought stress conditions in which theplant growth is less sensitive to nitrogen. Furthermore, the negative effect ofphosphorus on the yield of plant may be due to the inverse relationship between thesoil phosphorus and micronutrient elements on the plant growth. Generally, amongthe yield components, biological yield is the most important and effective trait ongrain yield, that has presented a significant contribution in different statisticalmethods. For some of the used statistical methods, the measured traits, like lengthof spike, the number of spikes per square meter, the number of grains per spikeand harvest index showed positive effects on the grain yield and other traits like1000-grains weight, the weight of grain per spike and the number of tillers withoutspikes per plant showed negative effects on the grain yield with the highestcorrelation. Among different soil nutrition, soluble potassium, phosphorus, sulfateand available potassium with positive effects and the clay content with negativeeffects showed the most correlation with the grain yield.

Relationships between wheat yield, yield components and physico-chemical properties of soil under rain-fed conditions Keywords:

Statistical analysis , Physico-chemical properties of soil , Morphological traits , Wheat grain yield