Inheritance of siliqua strength in Brassica campestris L. II. Quantitative genetic analysis

Quantitative genetic analysis of siliqua strength in Brassica campestris L. was conducted in the cross cv. Torch × DS-17-D using the North Carolina experiment II design. This revealed the presence of a high degree of nonadditive genetic variance and a high heritability (broad sense) for all measures of siliqua strength. These results are in accordance with earlier findings of the likelihood of a small number of genes controlling siliqua strength which interact epistatically.Key words: siliqua strength, shatter resistance, genetic variances (additive and nonadditive), heritability.

Inheritance of siliqua strength in Brassica campestris L. I. Studies of F2 and backcross populations

The inheritance of siliqua strength was studied in Brassica campestris L. using F1, F2, and backcross generations of crosses between cv. Torch (shatter susceptible) and var. Yellow Sarson and var. Brown Sarson (shatter resistant) accessions. Shatter resistance (high siliqua strength) was recessive in all crosses. Crosses involving DS-17-D (var. Brown Sarson) indicated that siliqua strength is most likely controlled by two genes that show dominant epistatic interaction. Crosses of IB-5 and B-46 (both var. Yellow Sarson) each with cv. Torch indicated the likelihood of three genes controlling siliqua strength, two of which appeared to be epistatic over the third gene when dominant. In these crosses, the multivalve character appeared to be controlled by three genes, two of which were epistatic over the third gene resulting in multivalve character when the former two were recessive. Segregation for siliqua strength in the var. Yellow Sarson crosses was not independent of segregation for multivalve character.Key words: Brassica, siliqua strength, shatter resistance, Sarson.