条斑紫菜双单倍体群体主要经济性状的遗传分析

条斑紫菜叶状体主要经济性状的遗传参数及相互间的遗传关系,是开展分子育种的基础。实验以条斑紫菜野生型品系(Py-WT2,父本)和红色突变型品系(Py-HT,母本)杂交后产生的杂合丝状体为材料,构建由152个品系组成的条斑紫菜双单倍体(DH)群体。该群体叶状体的6个经济性状(L50、W50、FW50、SGR-L、SGR-W、SGR-FW)的表型值用单样本Kolmogorov-Smirnov检验。结果发现,各性状均为数量性状。L50和SGR-W为超亲遗传性状,其余4个性状的变异介于双亲之间,其中W50偏向于母本,FW50、SGRL和SGR-FW偏向于父本。6个性状的变异系数介于21.11%~56.68%,均属中等强度变异。相关性分析表明,L50、W50和FW50相互之间均存在极显著正相关性,SGR-L、SGRW和SGR-FW相互之间也存在极显著正相关性。利用单因素方差分析法估算出L50、W50和FW50的遗传力分别为58.17%、64.00%和57.64%,控制3个性状的基因对数分别为6.61、12.63和8.09,遗传力(y)与基因对数(x)的二次回归方程为y=0.2922x~2–4.6533x+76.162(R~2=1)。基因间互作方式的检测结果显示,控制L50和控制FW50的多基因间均分别不存在互作;控制W50和控制SGR-W的多基因间均分别存在互补作用;控制SGR-L和控制SGR-FW的多基因间均分别存在重叠作用。研究表明,条斑紫菜叶状体L50和FW50的遗传力高、基因对数少且基因间无互作,可进行早代选择。另外,L50、W50和FW50之间的相关性高,可进行间接选择以提高育种效率。

Genetic analysis of major economic traits in Pyropia yezoensis using double haploid population

Genetic parameters of major economic traits and their relationships of gametophytic blades in Pyropia yezoensis are the foundation of molecular breeding. A double haploid (DH) population of 152 lines was developed from the heterozygous conchocelis of an intraspecific crossing of wild-type strain (Py-WT2, male parent) and red mutation strain (Py-HT, female parent). It was found that all 6 traits (L50, W50, FW50, SGR-L, SGR-W and SGR-FW) were quantitative traits when analyzed by one-sample Kolmogorov-Smirnov test. The means of 4 traits of DH population lines were between their parents, among which W50 was nearer to female parent, and FW50, SGR-L and SGR-FW were nearer to male parent. L50 and SGR-W showed transgressive inheritance, among which L50 was lower than low value parent (female), and SGR-W was higher than high value parent (female). Coefficient of variation of the 6 traits of DH population was between 21.11%–56.68%, which meant that they had intermediate variability. Highly significantly positive correlations were observed between L50 and W50, L50 and FW50, W50 and FW50, and between SGR-L and SGR-W, SGR-L and SGR-FW, SGR-W and SGR-FW. Heritability of L50, W50 and FW50 were 58.17%, 64.00% and 57.64%, respectively; and the number of genes controlling the 3 traits was 6.61, 12.63 and 8.09, respectively. The equation of the curve between heritability (y) and the number of genes (x) was y=0.2922x²-4.6533x+76.162 (R²=1). According to estimated coefficients of skewness and kurtosis of the 3 traits tested, gene interactions were found to be absent for L50 and FW50, respectively, and complementary interactions were observed in W50 and SGR-W respectively, and duplicate interactions were observed in SGR-L and SGR-FW respectively. The results indicated that L50 and FW50 could be selected at early generation by their high heritabilities, less controlling genes and no gene interactions, and indirect selection could be applied between L50, W50 and FW50 to improve breeding efficiency of P. yezoensis because of their high correlations between each other.