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Evaluation of variability in Striga aspera , Striga hermonthica and their hybrids using morphological characters and random amplified polymorphic DNA markers
Author(s) -
Emmanuel Izaka Aigbokhan,
D. K. Berner,
Lytton J. Musselman,
H.D. Mignouna
Publication year - 2000
Publication title -
weed research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 74
eISSN - 1365-3180
pISSN - 0043-1737
DOI - 10.1046/j.1365-3180.2000.00198.x
Subject(s) - hybrid , biology , striga , striga hermonthica , rapd , genetic distance , botany , genetic marker , genetics , genetic diversity , genetic variation , population , gene , germination , demography , sociology
Striga aspera and Striga hermonthica are recognized as separate species, but their close morphological similarity causes difficulty in distinguishing between them in areas where they coexist in Africa. In this study, crosses between the species were made using randomly selected morphologically typical parental plants collected from different locations in Nigeria. Genetic analysis of both species and their reciprocal F 1 hybrids were determined using cluster analysis of DNA profiles derived from genetic polymorphism (RAPD)‐polymerase chain reaction (PCR) markers. Principal component and hierarchical cluster analyses were used to separate parental and hybrid populations based on 13 morphological characteristics. Morphological data from wild samples of both species were compared with the hand‐pollinated parental, F 1 and F 2 hybrids, and back‐crosses. Results showed that S. aspera and S. hermonthica were genetically and morphologically distinct. Morphological and genetic analyses revealed two major clusters: a S. aspera cluster and a S. hermonthica cluster. Genetically, the F 1 hybrids showed closer affinity to their maternal parents, while morphologically, the F 1 hybrids formed distinct clusters intermediate to the parents. Most F 2 plants and back‐crosses were morphologically similar to S. hermonthica . Comparative morphological analysis of wild and hand‐pollinated populations showed some samples from the wild clustered with the hybrids, suggesting that hybrids may exist in nature.