In order to study the yield and yield components comparison correlation some physiological characteristics, 20 genotypes of bread wheat cultivars by modifying the old, and promising new lines selection and in a randomized complete block design (RCBD) with three replications in a farm field in Karaj Seed and Plant Improvement Research Institute from 1999 - 2000 was performed.data using statistical software (SAS) analysis of variance genotype and compared using duncan's multiple range test at 5% level was and simple correlation coefficients different characteristics of and its components to determine and then by linear regression and the stepwise between traits with grain yield were determined. Analysis of variance showed Figures of the traits seed yield , grain filling rate in the main spike, grain weight, harvest index, Plant grain weight, hectolitre index, the main stem spike length, flag leaf area, peduncle length and main stem, plant height, grain weight per spike main stem, main stem length, number of grains per spike in the likelihood of a significant percentage Yield of straw, and plant biomass at the five percent significance level The number of spike per unit area yield and protein content did not show significant differences. All number of genotypes with maximum yield of 8217 kg / hectare Up to 42% and harvest index Tajan and number with a minimum yield was 5348 kg/hectare. The highest correlation with the per hectare yield of grain filling period in the 1% level significant And positive (r = 0 . 83 **) was a negative correlation between the number of grains per spike and grain weight and significantly at the 1% level (r =- 0 . 64 **) respectively. The number of spikes per unit area , The number of grains per spike and grain weight of non-financial performance and significant positive correlation. This implies that the increased. function of grain per hectare, but these three are related and by stepwise regression on the trait most hectare, The grain filling period.
