ISHS Acta Horticulturae 760: XXVII International Horticultural Congress - IHC2006: II International Symposium on Plant Genetic Resources of Horticultural Crops
A NOVEL HOMEOTIC MUTANT WITH SEASON-DEPENDENT FLORAL ORGAN AND FERTILITY RESTORATION INDUCED BY 12C5+ ION-BEAM IRRADIATION OF SOLANUM VILLOSUM SEED |
| Authors: | C.O. Ojiewo, K. Murakami, M. Masuda |
| Keywords: | male-sterility, abnormal flower, partial fertility, superior leaf yield, Solanum nigrum complex |
| Abstract:
African nightshades (Solanum nigrum-related species) are important traditional green leafy vegetables whose yields are limited by prolific early flowering and excessive berry set in competition with leaf production. As a step towards elimination of this competition, male-sterile lines were developed through ion-beam irradiation. Locally collected S. villosum seeds from Kenyan farmers were subjected to 220 MeV 12C5+ ion beam irradiation at the Japan Atomic Energy Research Institute (JAERI), Gunma, Japan. At the M2 progeny, four male-sterile mutant types (T-1, T-2, T-3, T-4) similar to those reported from a previous γ-ray mutation were isolated. In addition, a novel abnormal floral organ mutant (T-5) was isolated and its flower structure further observed throughout the year. The mutant flowers were sepaloid in mid-spring, stamenless in late-spring, indeterminate in summer, partially restored with seeded berries in autumn, but the florets aborted at the bud stage in winter. The M3 progeny also showed a similar pattern. These phenotypes suggest a loss or impairment of function of one or more of B, C or E genes, the activation or repression of which seems to be under environmental influence. Partial fertility restoration and the resulting berry and seed set observed in autumn is advantageous for maintenance and seed propagation while the leaf-like flowers in spring, summer and winter form part of the vegetative yield. In a field trial, the T-5 had higher shoot-tip fresh and dry weights compared to wild-type (W-T) and other male-sterile mutants. | |
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