摘要
鉴于多倍体育种在杨树良种选育方面的优势,针对配子败育严重的毛白杨作母本杂交困难等问题,根据多年实地观察,选择结实率较高的毛白杨无性系3119、3532、8212为母本,银腺杨雄株YX1为父本,尽可能在雌蕊发育接近可授期时进行雌花枝水培,防止因营养不足而导致杂种胚败育的影响,在此基础上,选用39和42℃高温分别对授粉后4、16、28和52 h的雌花序持续处理2和4 h,并设置未施加高温处理的对照组合,同时同步固定与处理花序状态相同的毛白杨无性系3119的雌花序,组织切片观察统计胚囊发育过程各时期所占比例,以确定毛白杨胚囊染色体加倍与胚囊发育的相关关系。结果表明:3个杂交组合的各处理共获得458株毛白杨杂种三倍体,其中毛白杨3119×银腺杨组合共获得211株杂种三倍体,平均三倍体得率为57.97%;毛白杨3532×银腺杨组合共获得230株杂种三倍体,平均三倍体得率为65.71%;毛白杨8212×银腺杨组合共获得17株杂种三倍体,平均三倍体得率为70.83%,对照组合未获得杂种三倍体。从染色体加倍有效处理时期看,毛白杨3119雌花序在授粉后4~64 h均处于胚囊发育的3次有丝分裂内,不同花序间以及同一花序不同胚珠间表现出一定程度的不同步性,证明高温加倍获得的毛白杨×银腺杨杂种三倍体来源于胚囊染色体加倍;而从染色体加倍的处理温度和持续处理时间看,39、42℃的处理温度和2、4 h的处理持续时间均适宜于毛白杨胚囊染色体加倍,不同处理温度和不同持续处理时间之间并无太大差异。对杂种后代生长性状观察结果表明,各杂交组合的三倍体株高和地径平均值普遍高于二倍体。有关研究结果表明,高温诱导胚囊染色体加倍是一种高效获得杨树杂种三倍体的方法,对于毛白杨遗传改良具有重要价值。
Polyploid breeding is proved to be advantageous over other methods of breeding in Populus. Given the problem that cross breeding was very difficult in P. tomentosa when using those serious abortive gametes as female parents, P. tomentosa clones 3119, 3532 and 8212 with higher seed setting rate from many years of field observations were selected as female parents, and P. alba × P. glandulosa YX1 as male parent. Before chromosome doubling was carried out, female flower branches should be cultured in water while their pistil development was approaching receptive period, which can overcome the problem that gamete abortion was likely to happen because of malnutrition. During chromosome doubling of embryo sac, female catkins, 4, 16, 28 and 52 h after pollination, were treated for continuous 2 and 4 h by 39 and 42 ℃ high temperature exposure, respectively. And control groups were set without high temperature treatment. In addition, female catkins of P. tomentosa clone 3119 with the same conditions were fixed for paraffin sectioning, sections were observed and the percentages of embryo sac at different developmental stages were statistically counted for determining the correlation between chromosome doubling in embryo sac of P. tomentosa clone 3119 and the development of embryo sac. The results showed that, in total, 458 triploids were produced from the treatments of three cross breeding. Among them, 211 triploids were derived from the cross breeding between clone 3119 and P. alba × P. glandulosa, and the average rate of triploid production was 57. 97% with a total of 230 triploids came from the cross breeding between clone 3532 and P. alba × P. glandulosa, and the average rate of triploid production reached 65. 71%. However, only 17 triploids were screened from the cross breeding between clone 8212 and P. alba × P. glandulosa, with an average rate of triploid production of 70. 83%. No hybrid triploids were obtained in control groups. From the view of effective treating period, P. tomentosa clone 3119 female catkins after pollination 4-64 h were in the three mitosis periods of embryo sac development. There was a certain degree of asynchrony in different catkins and different ovules of the same catkin, suggesting that the obtained hybrid triploids by high temperature treatment were from chromosome doublings of embryo sac. Considering the temperature and duration of treatment, the temperature of 39, 42 ℃ and the duration of 2, 4 h are all suitable to P. tomentosa embryo sac chromosome doubling, and little difference was observed between 39 and 42 ℃, the same for duration between 2 and 4 h. Observations of growth traits in hybrid progenies revealed that the average height and ground diameter of triploid seedlings were larger than those of diploid individuals. Our findings interprete that, chromosome doubling of embryo sac with high temperature exposure is an efficient method for inducing triploid poplar hybrids, which has important values in genetic improvement of P. tomentosa.
出处
《北京林业大学学报》
CAS
CSCD
北大核心
2015年第2期79-86,共8页
Journal of Beijing Forestry University
基金
"十二五"国家科技支撑计划课题(2012BAD01B0302)
城乡生态北京实验室课题"环境友好型无飞絮白杨育种技术研究"
关键词
毛白杨
胚囊
染色体加倍
三倍体
诱导率
Populus tomentosa
embryo sac
chromosome doubling
triploid
rate of induction