Monogenic Segregations in Backcross Progenies of Capsicum baccatumx Two Interspecific F_1 Hybrids and Some Possible Explanations for Distorted Segregation Ratios in Capsicum

Authors: A. NACİ ONUŞ, BARBARA PICKERSGILL

Abstract: Monogenic segregations of certain morphological and isozymic characters were studied in backcross progenies of Capsicum baccatumL. ( Solanaceae) x two interspecific F_1 hybrids and distorted segregation ratios were noted. It was observed that isozyme markers Est-5, Idh-1, Pgm-2, and Pgi-2, and morphological marker gene P for fruit persistence showed distorted segregation ratios in the first backcross generation of both C. baccatumHawkes 6489 (P.G.Smith) x F_1 ( C. baccatum Hawkes 6489 x Capsicum cardenasii Heiser Smith) and C. baccatum SA219 (P.G.Smith) x F_1 ( C. baccatum SA219 x Capsicum eximiumA.T.Hunz). Both progenies and an excess of individuals carrying alleles inherited from C. baccatum. A further gene, y, controlling fruit colour and segregating in the backcross of C. baccatum Hawkes 6489 x F_11 ( C. baccatum Hawkes 6489 x C. cardenasii), also showed a distorted segregation ratio with an excess of homozygous individuals. However, in backcross families from interspecific crosses, Skdh-1 showed a distorted segregation ratio with an excess of heterozygous individuals.

Keywords: Morphological characters, isozymic characters, monogenic segregation, distorted segregation ratios

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