A GENETIC-STUDY ON CHARACTERISTICS OF CROWN LIGHT INTERCEPTION IN POPULUS-DELTOIDES

Light interception characteristics of 20 cottonwood clones (Populus de ltoides Basts. CV. 'Lux' x Populus deltoides Basts. CV. 'Harvard') wer e studied on one plantation in Nanjing. The main factors affecting lig ht interception efficiency of both population and individual trees are leaf area index, light extinction coefficient, the capacity of light interception, and lamina angle. Analysis on genetic correlation and he ritability shows that they are important for tree growth and genetic i mprovement. Different parts of the crown have different effects on tre e growth, and the effect of middle crown is the most important. The id eal crown structure of P. deltoides in this population is with bigger leaf area index in the upper crown and with smaller leaf area index an d more horizontal lamina angle in the middle and lower crowns.