| Poplar are the species collectively of Salicaceae Populus L..They are main afforestation of many countries in the world species, which are also important resource of tree species industrial plantation and ecological protective forest in China, because they are rapid growth, strong resistance, wide accommodation.Cross-breeding of artificial breeding is an important way for improving tree varieties. After the founding of the PRC, China's poplar forest workers cultivated successfully a large number of rapid growth, strong resistance varieties through artificial breeding,for example, Populus simonii×P.nigra P .popularis,Populus tomentosa Carr ,and etc. They are beneficial to improve the productivity of poplar in China and the level of improved variety system.The artificial crossing between Populus alba and P.salba×P.glandulosa,P.tomentosa was carried out in room and some hybrids were got from the two crosses. Growth-testing,the resistance diseases,insect pests and the traits of leaves were carried out in the second year, The results are as follows:1.The cross ability between Populus alba and P.salba×P.glandulosa,P.tomentosa is high and the fruit set rate after pollination of the two crosses reached 80% and 40% respectively, the germination rate of hybrid seeds is 75.32% and 80.00% respectively, and the rate of shoot survival is 53.7% and 41.5% respectively. The fruit set rate and rate of shoot survival of Populus alba×(P.salba×P.glandulosa) are high in comparison with Populus alba×P.tomentosa,respectively, but the germination rate of hybrid seeds of Populus alba×P.tomentosa is slightly high in comparison with Populus alba×(P.salba×P.glandulosa).2.The average seedling height and collar diameter of stumping seedling of Populus alba×(P.salba×P.glandulosa) are 2.06m and 1.55cm, Populus alba×P.tomentosa's are 2.09m and 1.61cm the growth increment of the two hybrids is near in this year.3.The seedling height variance coefficient of Populus alba×(P.salba×P.glandulosa)and Populus alba×P.tomentosa are 23.54% and 23.50%, the collar diameter variance coefficient are 23.05%和27.25% recpectively. The large variations in seedling height is useful for selection.4.The rate of disease and insect and the index of disease and insect all are lower in Populus alba×(P.alba×P.glandulos) seedling than Populus alba×P.tomentosa.So the resistant ability of disease and insect in Populus alba×(P.alba×P.glandulos) seedling all is higher than the Populus alba×P.tomentosa.Its offsprings show better resistant ability of disease and insect and the selection foundation.The resistant ability of leaf blight is lower black spot in the two crossing feedlings.So Its offsprings have better the resistant ability of leaf blight.5.The leaf length, leaf width, petiole length of Populus alba×(P.alba×P.glandulos) are 12.84cm,12.75cm,6.51cm recpectively. The leaf length, leaf width, petiole length of Populus alba×P.tomentosa are 12.15cm,11.52cm,5.76cm recpectively.So the leaf of Populus alba×(P.alba×P.glandulos) is slightly big in comparison with Populus alba×P.tomentosa's. From another point of view, ratio of length to breadth and the ratio of petiole length to principal vein length all describes the leaf shape, which are in middle of parents.It shows that the leaf shape has no major variation, the angle between the main vein and the second side the veins also proved this point more.6.From the combination of seedling height﹑collar diameter of stumping seedling﹑disease-resistant﹑pest-resistant traits, we did a total of five indicators of comprehensive evaluation, The former ranking is Populus alba×(P.alba×P.glandulos),the latter ranking is Populus alba×P.tomentosa.So comprehensive traits of Populus alba×(P.alba×P.glandulos) is better than Populus alba×P.tomentosa.They have a better choice foundation and advantages.7.We choosed 18 strains of superior individual in Populus alba×(P.alba×P.glandulos) seedlings and 2 strains of superior individual in Populus alba×P.tomentosa seedlings, according the standard of quantity and quality index.
|
PDF Full Text Request