The genetics and anatomy of lateral root patterns of Capsicum Annuum

Abstract

Individual plant selections designated as bidirectional and non-bidirectional lateral root patterns within 'El Paso Anaheim' and 'Jalapeno M' respectively were made. Crosses were made and the inheritance of lateral root patterns determined. Anatomical studies were also done to investigate the relationship between lateral root patterns and anatomy of primary vascular stele. The horizontal distribution patterns of lateral root primordia and lateral roots were also investigated. Bidirectional lateral root pattern in peppers appears to be under the control of a two sequential-gene system with complete dominance at both loci and either recessive being epistatic to the effects of the other gene. Homozygous recessives at either locus produce a non-bidirectional phenotype. The anatomy of the primary vascular stele in both cultivars was found to be a diarch. Differences in lateral root patterns were found to be due to differences in the origin of lateral root primordia rather than differences in the primary vascular stele anatomy. Lateral root organization in 'El Paso Anaheim' is precise and predictable while in 'Jalapeno M' it is less precise and unpredictable. Lateral root orientation with regard to their origin was found to be primarily determined by the vascular stele arrangement. The direction of lateral roots at germination is random and highly correlated with the orientation of the seed's hilum.