Effects of genetic improvement on traits of needle and cone of Cunninghamia lanceolata

Abstract

To reveal the effects of genetic improvement on leaf and seed traits of major afforestation timber species, and to clarify the variation trend of traits, selected trees (improved population) of the fourth cycle of Chinese fir breeding and phenotypic superior trees and ancient trees (unimproved population) in four provinces and five regions were selected as the research objects. The needle and cone traits of 218 clones were investigated, and the study used variance analysis and multiple comparison methods to study the phenotypic differences of genetic improvement on Chinese fir and different types of Chinese fir. The correlation analysis was used to explored the effect of genetic improvement on the phenotypic traits of Chinese fir needles and cones; the principal component analysis and cluster analysis were used for classification. The results were as follows: (1) The needle length, needle width and seeding rate of the unimproved population were 13.28%, 10.81% and 33.90% lower than those of the improved population, respectively. Other traits showed that the unimproved population was higher than the improved population, with differences ranging from 10.90% to 27.03%. The coefficients of variation of cone length, cone width and seeding rate of the unimproved population were 9.14%, 12.73% and 15.38% higher than those of the improved population, respectively. (2) Among the four traits of cone length, cone width, bract scale length and bract scale width, only cone length and cone width (0.931), bract scale length and bract scale width (0.622) were extremely significant positive correlation between them in the unimproved population. After genetic improvement, the four traits showed a significant or extremely significant positive correlation in pairs. (3) Cone length and cone width in Sichuan Ya’an (SCYA) were 48.83% and 53.26% higher than those in the improved population, and the hundred-grain weight in Anhui Huangshan (AHHS) was 16.92% higher than those in the improved population. (4) Genetic improvement led to a decrease in the proportion of Chinese fir with loose-stretched cones, and an increase in the proportion of Chinese fir with tightly packed and inverted cones. In summany, this study believes that the genetic improvement of Chinese fir leads to the reduction of cone size, changes the proportion of different needles and cone types, and changes the correlation between needle traits and cone traits, which will be helpful for providing the basis to the evaluation of Chinese fir germplasm resources and future multi-targets breeding.

Keywords

• cunninghamia lanceolata (chinese fir)
• genetic improvement
• breeding population
• needle
• cone