Characterization of the natural hybrid between two wild rice species (Oryza minuta Presl. and Oryza officinalis Well ex. Watt)

Abstract

The sterile wild rice population was compared with the parental species based on morphology, cytology, isozyme patterns and simple sequence repeat (SSR) loci. This population is believed to be a natural hybrid of O. officinalis and O. minuta. Characterization also included the two progeny plants (designated as F2 officinalis and F2 minuta based on morphology) produced from two seeds set by the putative hybrid. The morphology of the putative hybrid was more similar to that of O. minuta than that of O. officinalis. The F2 officinalis was taller (163 cm) and had longer panicles (25.80 cm). Its awns (36.99 mm) and anthers (3.04 mm) were longer and its spikelets were bigger (5.37 mm long and 2.27 mm wide) than those of the parents and the putative hybrid. The putative hybrid was a triploid (2n=3x) with 36 chromosomes. It had mean chromosome associations of (7.35I + 13.29II + 0.40III + 0.08IV), indicating the presence of two homologous (possibly CC) and a distantly related (possibly B)genomes. The F2 officinalis and F2 minuta have 56 and 52 chromosomes, respectively. Mean chromosome associations for the two F2 plants were (2.89I + 24.39II + 0.89III + 0.44IV) and (6.87I + 21.47II + 0.47III + 0.20IV), respectively. Zymograms in the putative hybrid and F2 plants were well within the range of enzymatic activities in both parents. Est-5, polymorphic bands in the parents were displayed in the putative hybrid. Likewise, at the molecular level, four polymorphic SSR primers that were amplified in the parents appeared in the putative hybrid. All evidences supported the hypothesis that the putative hybrid is a natural cross between O. minuta and O. officinalis.

Source or Periodical Title

Philippine Agricultural Scientist

ISSN

317454

Page

109-116

Document Type

Article

Subject

Isozymes, Natural hybrid, O. minuta, O. officinalis, Simple sequence repeat primers

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