Assessment of Reproductive Biology and Crossing between Adapted and Non –Adapted Clones of Populus deltoides Bartr

Abstract

Study on reproductive biology was conducted in selected male and female clones of Populus deltoides. Flower is dioecious and dichogamous in nature. Both male and female clones bear pendulous catkins with the male catkins are long reddish- purple and the female catkins are green in colour. Flowering occur once in year, during late February to April, 1 to 2 weeks before leaf initiation, strong anemophilous adaptations such as very high pollen output and light weighing winged seeds. Populus deltoides produces first seed at approximately 10 years of age. The capsule and seed set percentage is very high, if there is no seed set in bagged inflorescence indicating cross pollinating nature. But in cross pollination resulted in lower seed set than observed in open pollination. Pollen germination rates were affected by sucrose concentrations and the solution containing 2% and 15% sucrose concentration had the highest germination rates than 1%, 5% and 10% sucrose concentration. The significant differences for crossability parameters viz., successful crosses (%), germination (%) and survival (%) among the clones of Populus deltoides. The overall performance of G-48 X S7C1 and Kranthi X 25-N hybrids were found outstanding for most of morphological traits.