Breeding of triploids by the reciprocal crossing of Populus alba×P.glandulosa and P. tomentosa×P.bolleana.
Kang Xiangyang;Zhu Zhiti;Zhang Zhiyi. Institute of Populus tomentosa, Beijing For. Univ.,100083, P.R.China.
Sixteen triploids were successfully obtained from the hybridization between P. alba ×P. glandulosa and P. tomentosa×P. bolleana by using unreduced 2n pollen and treating the pollen with radiation. The best treatment for the combination of ( P. alba ×P. glandulosa) ×(P. tomentosa×P. bolleana ) was 1?470 rad and the ratio of obtained triploids was 3.8%, while for the combination of ( P. tomentosa×P. bolleana) ×(P. alba ×P. glandulosa ) the best treatment was 1 680 rad and ratio was 12.9 %. The growth of triploids showed obvious superiority over normal diploids, and more out standing for a single tree. Stem height and basal diameter of 2 year old triploid seedling reached 4.9 m and 5.8 cm respectively, being 50% and 176% larger than the average growth. The difference in genetic effect of the triploids obtained from two different combinations was significant. The results suggested that breeding and selecting hybrid triploids by using unreduced 2n pollen and treating the pollen with radiation will be one of the most effective means for the future breeding of white poplar and even other members of Populus.