Genetic Variation of Growth Traits and Genotype-by-Environment Interactions in Clones of Catalpa bungei and Catalpa fargesii f. duclouxii

Abstract

Clones of Catalpa bungei and Catalpa fargesii f. duclouxii were studied over several years in central China to explore genetic variation in growth traits and to identify clones of high wood yield and high stability. The genetic parameters for height, diameter at breast height (DBH), and stem volume of clones, were estimated. The effect of clone × year on the increment of stem volume in the two species was analyzed by genotype and genotype × environment (GGE) biplot methods. Significant differences in growth traits among clones and between species were found. The growth of C. bungei exceeded that of C. fargesii f. duclouxii after 4 years. Furthermore, from the 5th year, the repeatability and genetic variation coefficient (GCV) of the C. bungei clones were higher than those of the C. fargesii f. duclouxii clones in most cases. The phenotypic variation coefficient (PCV) of the C. fargesii f. duclouxii clones was significantly lower than that of the C. bungei clones. The repeatability of stem volume was intermediate or high in the two species. ANOVA revealed significant effects of the clone by year interaction in these two species. GGE biplot analysis revealed that wood yield and stability were largely independent in C. bungei; clones 22-03, 19-27, and 20-01 were the optimal clones in this species. In contrast, the optimal clones 63 and 128 of C. fargesii f. duclouxii combined the desired characteristics of high yield and high stability. In conclusion, our results indicated that the height and stem volume of C. bungei was under strong genetic control, whereas that of C. fargesii f. duclouxii was influenced by the environment more than by genetic effects. Genetic improvement by clone selection can be expected to be effective, as the repeatability of stem volume was high. Francis and Kannenberg’s method and GGE biplot analysis were used in combination to evaluate the clones. C. bungei clone 22-03 and C. fargesii f. duclouxii clones 63 and 128 were identified as the optimal clones, which exhibited both a high increment of stem volume and high stability.

Phenotypic Variability and Genetic Diversity in a Pinus koraiensis Clonal Trial in Northeastern China

“…Similar findings were reported on many tree species, indicating that selection based on phenotypic variation results is feasible [60][61][62][63]. Considering the extent of phenotypic variation, the clone variability in PCV values (%) seems to be slightly lower compared to prior P. koraiensis variation studies [9,10]; this is likely due to the age difference in Korean pine materials used in each study [61], the genetic properties (clone against families), planting design and different environmental conditions. The material age is an important factor in growth variation of planted trees that share similar environmental conditions, and growth sizes seem to be uniform among mature trees [64].…”

Deciphering Genetic Architecture of Adventitious Root and Related Shoot Traits in Populus Using QTL Mapping and RNA-Seq Data

“…Repeatability was calculated using the variance parameter following the formula: R = ơ 2 c /(ơ 2 c + ơ 2 e ). Where ơ 2 c and ơ 2 e were the estimates of variances between-clone and within-clone, respectively [46].…”

Transcriptomics and Proteomics Reveal the Cellulose and Pectin Metabolic Processes in the Tension Wood (Non-G-Layer) of Catalpa bungei

“…What is more, most studies on TW have focused on G-layer species because poplar is a model tree and maintains a G-layer, few studies have been conducted on TW without a G-layer. Catalpa bungei is native to China and has high-quality timber [24]; thus, it is an important timber tree and a good material for genetic improvement of wood properties. Based on our previous study, there is no obvious G-layer in TW of C. bungei.…”