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杉木(Cunninghamia lanceolata)是我国特有的用材林树种,是南方地区栽培历史最为悠久、经济价值高的用材林树种[1],四川是杉木的西部主产区,主要分布在盆周山地和川中丘陵区[2],是速丰林工程建设的主要树种,也是筑牢长江上游生态屏障和建设国家储备林的重要树种,因此,发掘杉木优良种质,开发早期鉴定技术,对四川林业高质量发展具有重要作用。杉木人工林高质量发展的基础是选用良种壮苗,在杉木遗传改良工作中,四川已经建成出多个种子园并投入使用,前人的研究主要集中在杉木种子园选优、建园材料选择、自由授粉子代测定分析等方面[3-6]。较少涉及球果、种子和苗期特征等材料性状间遗传关系。相关遗传力是两个性状的遗传协方差与两性状表现型标准差乘积之比,能将性状表型值、基因型值、遗传力和相关系数联系起来[7]。由于相关遗传力矩阵在比较目标性状与辅助性状的遗传力与遗传相关时直观、简便,使分析更有效可靠。研究表明,当目标性状与辅助性状的相关遗传力的绝对值大于目标性状遗传力时,可以用辅助性状来间接选择目标性状[7-10]。以四川省高县月江国有林场杉木第2代种子园中5个自由授粉家系为研究对象,研究了球果、种子和苗期性状的遗传变异情况和相关遗传力,以期为杉木半同胞子代的早期鉴定提供依据。
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杉木球果直径方差分析结果发现家系之间存在显著性差异,多重比较表明,5个家系球果的直径可分为四个级别,直径最大的为T88,其次为T120,再次为T78和T80,平均直径最小的为T313。T313最大的球果直径与T120最小的球果直径相当(见表1)。
性状
Traits家系号
Family number均值±标准差
mean±standard deviation极小值
Minimum极大值
Maximum变异系数
Variation coefficient/%直径
Diameter/cmT88 2.85±0.16a 2.6 3.1 5.48 T120 2.64±0.18 b 2.3 2.8 6.53 T78 2.26±0.18 c 2 2.6 7.63 T80 2.37±0.15 c 2 2.6 6.12 T313 2.04±0.18 d 1.7 2.3 8.83 长度
Length/mmT88 3.42±0.24a 3.1 4 7.01 T120 3.29±0.22a 2.8 3.6 6.39 T78 3.01±0.33 b 2.4 3.6 10.74 T80 2.70±0.25 c 2.2 3 9.17 T313 2.84±0.21 bc 2.4 3.2 7.21 质量
Weight/gT88 16.41±3.05a 12.9 23.4 18.14 T120 13.16±2.27 b 9.4 17.6 16.85 T78 8.69±1.85 c 5.9 12 20.83 T80 10.31±1.55 c 7.5 13.4 14.65 T313 9.02±1.70 c 4.9 11.2 18.26 注:同列不同小写字母表示差异显著(P<0.05)(下同)。
Note: Different lowercase letters in the same column indicate significant differences (P<0.05) (the same below).Table 1. Multiple comparison of cone characters in Chinese fir families
杉木球果长度方差分析结果发现家系之间存在显著性差异,多重比较表明(见表1),5个家系球果的长度以3 cm为标准,可分为大中小三个级别,长度最大的为T88和T120,其次为T78,T80和T313为球果平均长度最小两个家系。
杉木球果质量方差分析结果发现家系之间存在显著性差异,多重比较可将5个家系分为3个级别(见表1),杉木球果质量最大的为T88,其次为T120,从极值看,各家系球果质量均表现出1倍的差距。
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5个家系种子的千粒重、发芽率和发芽势等性状见表2。5个家系种子平均发芽势为7.67%~20.50%,方差分析结果表明家系间有显著性差异,多重比较结果发现T120的平均发芽势显著高于其他家系,T80次于T120,T88和T78的平均发芽势最低,说明家系间在发芽整齐度上差异较大。结合表1,可发现发芽整齐度与球果大小间无强关联。
家系号
Family number平均千粒重
Average thousand-grain weight/g平均发芽率
Average germination rate/%平均发芽势
Average germination potential/%T88 10.66±0.26a 49.80 7.67d T120 10.48±0.29a 52.80 20.50a T78 7.62±0.18b 51.80 7.83d T80 4.6±0.16c 50.60 15.00b T313 4.22±0.30c 49.60 11.83c Table 2. Multiple comparison of seed characters in Chinese fir families
而5个家系种子平均发芽率均在50%上下,且相互之间无显著性差异,说明最终出苗量没有差异,因此各家系的场圃播种量一致即可,无需按家系单独配置。
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5个杉木家系苗期测定见表3,各家系子代苗高均在20 cm以上,其中T120和T80的平均苗高达到了一级苗的要求(苗高≥24 cm),T78平均苗高接近一级苗的标准。
性状
Traits家系号
Family number均值±标准差
mean±standard deviation极小值
Minimum极大值
Maximum变异系数
Variation coefficient/%苗高
Seedling height/cmT88 21.1±5.24ab 12.00 33.00 24.83 T120 29.28±5.96a 19.00 41.00 20.36 T80 28.12±5.52a 20.00 39.00 19.63 T313 22.59±3.27b 17.00 31.00 14.48 T78 23.59±5.37b 13.00 40.00 22.76 地径
ground diameter
/mmT88 5.91±1.54b 3.16 9.74 26.06 T120 7.09±1.48a 4.42 10.79 20.87 T80 6.27±1.19ab 3.77 8.56 18.98 T313 5.72±1.09ab 3.42 7.85 19.06 T78 6.37±1.43b 4.02 9.38 22.45 Table 3. Comparison of offspring traits of Chinese fir families
各家系子代苗地径均值均达到了一级苗的标准(地径≥4 mm),其中T120和T78的最小值均达标,说明这两个家系子代的地径指标全部达标,其中,T120子代单株最大地径达到10.79 mm,T78和T88子代单株最大均超过了9 mm。
3个家系的苗高变异系数达到或接近20%、3个家系地径变异系数超过了20%,表明家系内苗高和地径性状变异丰富。
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球果与幼苗性状遗传力、相关遗传力和表型相关系数结果见表4,球果与球果性状的遗传力均达到0.9以上,幼苗苗高遗传力为0.8134,性状受到强烈的遗传控制,能够稳定的遗传给子代,而幼苗地径遗传力相对较低,为0.6388,能较为稳定的遗传给子代。
性状
Traits幼苗苗高
Height of seedling球果直径
Cone diameter球果长度
Cone length球果质量
Cone weight幼苗地径
Seedling ground diameter幼苗苗高Height of seedling 0.8134 −0.0393 0.62 −0.0493 0.1397 球果直径Cone diameter −0.0278 0.9862 0.776 0.9949 −0.3311 球果长度Cone length 0.5966 0.7848 0.9743 0.7726 0.0443 球果质量Cone weight −0.0437 0.9992 0.7757 0.9949 −0.3039 幼苗地径Seedling ground diameter 0.3728 −0.3279 0.0004 −0.3013 0.6388 注:对角线为是遗传力,上三角是相关遗传力,下三角是表型相关系数。 Table 4. Phenotypic correlation coefficients and relative heritability among traits in Chinese fir cones and seedlings
相关遗传力代表了性状间相互间接选择的效率,根据戴君惕等[7]的方法,A性状选择B性状的效率为两性状相关遗传力与B性状遗传力之比。从表4可知,球果性状的相关遗传力较高,如球果质量与球果直径相关遗传力等于球果质量遗传力,因此当两相关性状选择强度相等时,通过球果直径对球果质量的间接选择相对效率为100%,与直接选择效率一致。
而幼苗性状与其他性状的相关遗传力较低。各性状与幼苗苗高的相关遗传力依次为:球果质量>幼苗地径>球果直径>球果长度,各性状与幼苗地径的相关遗传力依次为:幼苗高度>球果长度>球果质量>球果直径。由此可知,幼苗苗高和地径等2个性状与球果性状的相关遗传力均小于幼苗2个性状的遗传力,因此,通过球果性状对幼苗性状进行间接选择的效果不明显。
表5结果显示,幼苗苗高和幼苗地径为中度相关,幼苗苗高和球果长度为高度相关,球果性状之间为高度相关,但p值均>0.05,说明性状间的遗传相关系数均未达到显著水平,也验证了相关遗传力的结论,说明性状间基本未受到相同基因的遗传控制。
性状
Traits幼苗苗高
Height of seedling球果直径
Cone diameter球果长度
Cone length球果质量
Cone weight幼苗地径
Seedling ground diameter幼苗苗高Height of seedling 1 0.6498 0.2877 0.7733 0.497 球果直径Cone diameter 0.3338 1 0.2446 0.0797 0.7475 球果长度Cone length 0.7654 0.8191 1 0.242 0.6511 球果质量Cone weight 0.21 0.9771 0.8222 1 0.915 幼苗地径Seedling ground diameter 0.5036 0.235 0.3324 0.0773 1 注:左下角是遗传相关系数,右上角是p值。
Note: The genetic correlation coefficient is in the lower left corner, and the p value is in the upper right corner.Table 5. Genetic correlation coefficient and significance analysis of various traits of Chinese fir cones and seedlings
Analysis on Variation and Correlative Heritability of Cone, Seed and Seedling Traits in Families of Cunninghamia lanceolata
doi: 10.12172/202211090002
- Received Date: 2022-11-09
- Available Online: 2023-03-06
- Publish Date: 2023-06-25
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Key words:
- Cunninghamia lanceolata /
- Family /
- Cone Traits /
- Seedling Traits /
- Correlative Heritability
Abstract: By comparing the changes of genetic correlation of cone traits, seed traits and seedling traits among Chinese fir semi-sib families, as well as the degree of genetic correlation between traits, the variation of seed and seedling tratis of Chinese fir at the family level was revealed, and the possibility of early selection of seedlings through seed and seedling traits was discussed. Using the cones of five half-sib families which were from the second-generation seed orchard of Gaoxian Yuejiang state-owned forest farm as materials, the cone diameter, cone length, cone quality, 1000-seed weight, germination rate, germination potential, seedling height, and ground diameter were measured with 10 replicates for each family, the relative heritability and genetic correlation coefficient between traits were estimated. The results showed that: (1) There were significant differences in cone diameter, cone length and cone quality, 1000-seed weight and average germination potential among the five families. The average germination rate of the five families was about 50%, and there is no significant difference. Therefore, when sowing, there was no need to set the sowing amount by family; (2) The average seedling height of all families was more than 21 cm, and the coefficient of variation of seedling height of four families reached or approached 20%, with significant differences among families. The average diameter of seedlings of all families was more than 5 mm, and the coefficient of variation of diameter of all families was more than 18%, which indicated that it was potential to select super seedlings. (3) The heritability of cone was above 0.9, and the heritability of seedling height and ground diameter were 0.81 and 0.64 respectively. The correlation heritability between cone traits and seedling traits was less than that of seedling traits, and the genetic correlation coefficient was not significant. Therefore, it was impossible to select seedlings by cone traits,