Genetic and Heterosis Analysis of Opening Degree of Upper Leaves of Flue-Cured Tobacco

Li Changyuan; Tang Qin; Cui Shuai; Wang Yu; Shi Chenhao; He Yifei; Zhang Junting; Liu Renxiang

doi:10.14083/j.issn.1001-4942.2025.11.004

Abstract：Opening degree of upper leaves was an important agronomic trait influencing yield and quality of tobacco leaves.In order to breed tobacco germplasms with good opening degree of upper leaves,11 flue-cured tobacco varieties(lines)with large difference in upper leaf area were used as parents,28 hybrid combi-nations were combined by NCⅡgenetic design,and the genetic characteristics and heterosis of the upper leaf opening degree of flue-cured tobacco were analyzed by measuring the length and width of the upper leaves.The results showed that there were significant differences in leaf length,leaf width and opening degree between dif-ferent materials,and the correlations of opening degree with leaf length and leaf width were very significant,and the direct path coefficients were-0.496 and 0.941,respectively,indicating that the opening degree was mainly affected by leaf width trait.The heritability of opening degree and leaf width were higher with the broad-sense heritability as 54.04%and 52.68%and the narrow-sense heritability as 41.53%and 22.07%,respec-tively.The parent GDH64 had the largest general combining ability of opening degree and leaf width as 15.03 and 8.91,while the combination of NC82×Yunyan 87 had the largest special combining ability of opening de-gree and leaf width as 10.94 and 9.33,respectively.The proportion of combinations with positive heterobeltio-sis in opening degree and leaf width in the 28 hybrid combinations were 25.00%and 28.57%,respectively.In conclusion,the opening degree of upper leaves of flue-cured tobacco was mainly affected by leaf width,and had higher heritability with obvious heterosis;GDH64 was an excellent parent to improve the opening degree of upper leaves,and the hybrid combination NC82×Yunyan 87 had better upper leaf opening and greater explo-ring and application potential.