The effect of planting density and weed interference on agricultural traits of different rapeseed genotypes in Darab Region using multivariate statistical methods

This study was carried out to evaluate the effect of planting density and weed interference on agronomic traits of different rapeseed genotypes in Darab region using multivariate analysis methods. To evaluate the physiological, morphological, yield and yield components of rapeseed genotypes, a split plot experiment was carried out based on a randomized complete block design with three replications in Fars province (Darab County, Forg District) during 2015-2017 (for two years). The treatments included main plot of plant density (densities of 20, 40, and 60 plants per m2) and sub plot included complete weeding, non-weeding and weeding at the rosette stage. Moreover, sub plots included cultivars (Hayola 401, Sarigol, and RGS003). Simple and compound ANOVA, stepwise regression, and correlation were calculated using SAS software, and main components were analyzed using minitab16 software and charts were drawn using Excel software. Means were also compared using the Duncan's multiple range test (DMRT) at a confidence level of 5%. The results of the analysis of the variance of measured traits showed that density, weeding, cultivar, interaction of density x weeding, weeding x cultivar, and density x weeding x cultivar and interaction of density x weeding x cultivar and interaction of density x cultivar were significant in both crop years and in compound analysis of two years at 1% probability level. The results of this experiment showed that density of 20 increased leaf area, number of lateral branches, plant height, stem diameter, number of pods of main stem, pod length, distance from first pod to ground, fresh pod weight, number of seeds per pod, weight of 1000 seeds, and seed and oil yields as compared with density of 60. Comparison of mean of weeding effect on leaf area, plant height, number of main stem pods, distance from first branch to ground, stem diameter, pod length, distance from the first pod to ground, fresh pod weight, weight of 1000 seeds, seed and oil yield showed that complete weeding and non-weeding have the maximum and minimum numerical values, respectively. Comparison of mean of cultivar effect on leaf area, plant height, and distance from first pod to ground showed that Sarigol had the maximum leaf area as compared with Hayola 401. Also, the results showed that Hyola 401 cultivar had more yield than other cultivars.