Analysis of Culture‐Induced Variation in Soybean

Abstract

Genetic variation among culture‐regenerated crop plants can be a source of novel and desirable genetic diversity, or it can be a source of detrimental and agronomically unfavorable phenotypic variability. The objectives of this research were to determine the frequency and types of somaclonal variants obtained from culture regenerated soybeans [Glycine max (L.) Merr.]. Four hundred seventy‐five plants were regenerated from nine soybean cultivars via direct somatic embryogenesis from cotyledons of immature zygotic embroyos. Their R1, R2, and R3, progeny were scored for qualitative variation and inheritance of variant phenotypes. In each generation, sufficient numbers of progeny from R0, R1, and R2 plants were grown to ensure a 95% probability of recovering a homozygous recessive phenotype, assuming single‐gene inheritance. Phenotypic variation was observed in the R0, R1, R2, and R3 generations. Variant phenotypes included partial sterility (R0, R1, R2), complete sterility (R0,), abnormal leaf morphology (R0, R1, R2, R3), chlorophyll chimeras (R2, R3), chlorophyll‐deficiencies (R2, R3), changes in growth habit (R2, R3), yellow edges on cotyledons (R3,), no unifoliates (R3), dwarf plants (R2), yellow‐green plants (R3), and isozyme variants (R2). Inheritance studies of chlorophyll‐deficient, curled leaf, and wrinkled leaf plants confirmed that these traits were genetically controlled. Segregation for genetically controlled traits initially was observed in the R2 generation. This study produced variant phenotypes not previously reported that have potential for contributing to the understanding of the soybean genome.