Genotypic differentiation in Microlaena stipoides populations: Morphological and ecological patterns

Abstract

Patterns of divergence among four Microlaena stipoides populations growing in association with four perennial grasses, Lolium perenne [M (Lpe)], Poa pratensis [M (Ppr)], Dactylis glomerata [M (Dgl)] and Phalaris aquatica [M (Paq)], in permanent pastures were examined. Of the four associated populations, M (Lpe) and M (Paq) had shorter but broader leaves and larger, heavier grains. M (Ppr) had narrower leaves, more tillers and smaller grains. M (Ppr) had the fastest rate of seed germination at 25 C while seeds of M (Paq) had the slowest germination rate. M (Ppr) showed greatest vegetative and reproductive growth under 6% light intensity while M (Dgl) showed greatest tolerance to full light. M (Paq) and M (Dgl) showed higher tolerance to water stress than M (Lpe) and M (Ppr). Amplified polymorphic DNA fingerprints showed that M (Ppr) had the greatest divergence in the DNA banding patterns. The patterns of variation showed that local population differences occurred among M. stipoides populations growing with different neighboring perennial grasses in a permanent pasture. These variations may have evolved through natural selection resulting from competitive interactions with associated perennial grasses, variation in light intensity, water availability or other factors in the environment.

Source or Periodical Title

Philippine Agricultural Scientist

ISSN

317454

Page

159-172

Document Type

Article

Subject

DNA fingerprinting, Light intensity, Microlaena stipoides, Natural selection, Plant populations, Water stress tolerance

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