Excellent Parents Comprehensive Selection In Triploid Seed Orchard Of Betula Platyphylla

Carrying test for seed tree and progeny in seed orchard, selecting and evaluating hybrid parents in a early stage not only can effectively promote the upgrading of seed yield and quality, but also accelerate the improvement of seed orchard and shorten the breeding cycle, which has significance. In this study, seed orchard of birch triploid was used as object for measuring flowering phenology, seed yield and fiber material and other traits. Meanwhile, growth traits of birch triploid offspring were measured. The results of hybrid parents and offspring selection and evaluation provided a scientific basis for the improvement of birch triploid seed orchard.The main results included:Test of seed tree found that receptive stage of female inflorescence was a little earlier than male shedding time and lasted long time. End time of female inflorescence and shedding stage were basically synchronous, or one day earlier. According to above phenomenon, we thought that flowering phase of female inflorescence and male were basic accordance. In the aspect of seed production, seed tree Q71, Q55 and Q52 had the best performance and has reached the scale seed, which for three consecutive years seed quantity of these three seed tree were 3.79,3.44 and 2.61 times of the rest seed tree, respectively. In the aspect of fiberwood properties, seed tree 8419,8412, Q108, CK14, Q56,848, Q44, Q96,8413 and Q52 had the better performance and the content of wood density, fiber length, fiber length to width ratio,and ensemble cellulose were higher 5.72%, 5.07%,5.72%,2.49%than the group mean. Lignin content was lower 9.33%than the group mean. These seed tree were preferred pulpwood oriented breeding mother tree.Testing results of 18 half-sib families seed characteristics and seedling traits of birch triploid showed that Q53, Q65 and Q13 were better than other families in seed thousand weight, seed vigor and seedling growth. CK13, CK14 and Q27 were outstanding in seed vigor and growth traits. Q44 was better in seed thousand weight and vigor. The evaluation of 24 birch triploid full-sib families, which were obtained from control pollination, indicated that offspring, which mother tree were Q13, Q103, Q33 and Q83, performed better. And offspring, which father tree were F3(CK27^ F4(CK4)、F9(CK3), perform superior. Among these mother parents, Q13 was the best, and its offspring were higher 13.82%,7.01%than the overall average in height and ground diameter. Among these father parents, F3 was the best, and its offspring were higher 7.95%,2.91%than the overall average in height and ground diameter. F3×Q13 、F4×Q83、F9XQ33、F9×Q13andF3 X Q33 were excellent hybrids, average height, ground diameter of these three excellent hybrids were higher than the group average of 18.88%and 8.19%. Multi-sites stability analysis of birch triploid indicated that 203 and 201 were the best families with the best growth performance and strongest stability,309,308,205,316,302, and 206 were better families with better growth performance and stronger growth adaptability.