Relationship between leaf area index, biomass and winter wheat yield obtained at Fundulea, under conditions of 2001 year

Abstract

Several data of the ADAM (Assimilation of Data within Agricultural Models) project were used to establish the relationships between agronomic variables of winter wheat. During the campaign 2000-2001, ten calibration units from seed production farms of A.R.D.I. Fundulea were selected based on several factors of variation, such as: the cultivar (Dropia and Flamura 85); the preceding crops, soils with different microtopography and nitrogen fertilization. Positive correlations between leaf area index and biomass of winter wheat in different developmental phases were found (from r = 0.66 * to r = 0.84***). The bio-mass was correlated with yield (r = 0.65*), number of seeds and number of ears/m 2 (r = 0.63*, r = 0.72**), too. The results of regression analysis indicate that polyno-mial models gave the best fit for regression of total bio-mass and LAI (max) on harvest index and linear model for grain yield. The coefficients of determination be-tween harvest index and total biomass are smaller than those between harvest index and grain yield. This means that wheat crops with the highest harvest index do not necessarily have the highest biomass accumulation. In fact, the opposite can be true. The magnitude of coeff i-cient of determination for the regression of total bio-mass and grain yield on harvest index indicates that ap-proximately 0.34 % of the total variation of total biomass can be attributed to variation in harvest index of the ana-lysed wheat crop. The low correlation of this study be-tween LAI and TKW (r = 0.29) indicates that these two traits are largely independent of each other. In fact, TKW depends on the genetic background as some research-ers have reported. Key words: leaf area index (LAI), winter wheat biomass, grain yield