基于混合线性模型的高州油茶杂交亲和性遗传评估Ⅰ

Genetic evaluation for the cross-compatibility between lines of Camellia gauchowensis and other species based on mixed linear model

【目的】提高杂交选育效率,提高南缘油茶的产量,改良其品质。【方法】选取高州油茶4个优树无性系,小果油茶、普通油茶和香花糙果茶各1个无性系,开展5×7的人工控制授粉试验。检测参试亲本染色体倍性,统计杂交试验的授粉花朵保存数量、保存率、坐果数量和坐果率,采用混合线性模型估算不同无性系间亲和性的一般配合力和特殊配合力等遗传参数,综合评估各组合的杂交亲和性,最终确定杂交优势亲本。【结果】参试亲本中,小果油茶是六倍体,普通油茶是八倍体,高州油茶和香花糙果茶是十倍体。40株母树共授粉套袋1 866个,保存1 465个,坐果713个,保存率在母本间差异达极显著水平(P=0.002),坐果率在父本间(P=0.002)和母本间(P <0.001)差异均达极显著水平。♀CG2和♂CG1组合的坐果率在不同组合间的二维交互效果最好。父、母本间平均坐果率最高的分别是香花糙果茶(♂CF1,63.92%)和高州油茶(♀CG2,55.14%)。保存数量和坐果数量配合力混合模型中母本加性效应值高于父本;高州油茶坐果数量的母本一般配合力表现最高的是CG3(0.157),父本一般配合力最高的是CG1(0.137)。坐果数量组合间♀CG2×♂CG1的特殊配合力最高(0.177),其次是♀CG3×♂CG2(0.139)。【结论】高州油茶种内杂交亲和性普遍高于种间杂交。香花糙果茶不适宜作为高州油茶、小果油茶和普通油茶的杂交母本,更适合作为父本或配置授粉树;高州油茶、小果油茶和普通油茶杂交可互为亲本,坐果率差异化和染色体倍性以及亲缘关系密切相关。综合杂交亲和性各遗传参数,CG3可作为优势母本,CG1可作为优势父本。

【Objective】To improve the yield and quality of camellia oil in south area of China by increasing the efficiency of hybrid breeding between camellia species and cultivated varieties.【Method】Four clones of Camellia gauchowensis and each one clone of C. meiocarpa, C. oleifera and C. suaveolens were selected to test in a 5×7 pollination experiment.After detecting the chromosome ploidy for each parent, the preservation number of pollinated flowers, preservation rate of pollinated flowers, fruit setting number and fruit setting rate of pollination for the cross parents were counted. The genetic parameters such as general combining ability(GCA) and special combining ability(SCA) were estimated by using mixed linear model. And the hybrid compatibility of all combinations was evaluated comprehensively to determine the dominant parent in the end.【Result】Among the tested parents, C. meiocarpa was hexaploid, C. oleifera was octeploid, C. suaveolens and C. gauchowensis were tenploid. 40 female trees were pollinated with 1866 flowers, 1465 preservation number of pollinated flowers were record, and 713 fruit number were kept at last. There were significant differences in preservation rate of pollinated flowers among females(P=0.002), and fruit setting rate also presented significant differences among females(P < 0.001) and males(P=0.002) in variance analysis. The fruit setting rate of ♀CG2 and ♂CG1 showed the best interaction effect in the two-factor analysis of variance among combinations. The highest average of fruit setting rate among female was CG2 with 55.14%, and the highest average of fruit setting rate among male was CF1 with 63.92%. The additive effect of female parent was the highest variance component in the mixed model analysis for combining ability of preservation number of pollinated flowers and fruit setting number. The highest GCA effect value of female parent for fruit setting number was CG3with 0.157, and the male parent was CG1 with 0.137. The best combination of SCA effect value was ♀CG2 × ♂CG1 with 0.177, followed by ♀CG3 × ♂CG2 with 0.139.【Conclusion】The intraspecific cross affinity of C. gauchowensis is generally higher than interspecific cross. The species of C. suaveolens Ye. is not suitable as a female parent crossing with parents of C.gauchowensis, C. meiocarpa, and C. oleifera, which is more compatible as a male parent or configurated pollination tree. The species of C. gauchowensis, C. meiocarpa, and C. oleifera can be parents to each other in hybridization, and the difference in fruit setting rate is closely related to the chromosome ploidy and genetic relationship. According to the genetic parameters of cross compatibility, CG3 could be the dominant female parent and CG1 could be the dominant male parent.