Comparison of chickpea rhizobia isolates from diverse Portuguese natural populations based on symbiotic effectiveness and DNA fingerprint.
OBJECTIVE
To test the hypothesis that differences in chickpea yields obtained in four distinct Portuguese regions (Beja, Elvas-Casas Velhas, Elvas-Estação Nacional de Melhoramento de Plantas (ENMP) and Evora) could be due to variation between the natural rhizobia populations.


RESULTS
Estimation of the size of the different rhizobial populations showed that Elvas-ENMP population was the largest one. Elvas-ENMP population also revealed a higher proportion of isolates carrying more than one plasmid. Assessment of genetic diversity of the native rhizobia populations by a DNA fingerprinting PCR method, here designated as DAPD (Direct Amplified Polymorphic DNA), showed a higher degree of variation in Elvas-ENMP and Beja populations. The symbiotic effectiveness (SE) of 39 isolates was determined and ranged 13-34%. Statistical analysis showed that SE was negatively correlated with plasmid number of the isolate.


CONCLUSIONS
The largest indigenous rhizobia population was found in Elvas-ENMP. DAPD pattern and plasmid profile analysis both suggested a higher genetic diversity among the populations of Elvas-ENMP and Beja. No relationship was found between SE of the isolates and their origin site.


CONCLUSIONS
The large native population, rather than the symbiotic performance of individual rhizobia, could contribute to the higher chickpea yields obtained in Elvas-ENMP.
Laranjo
M
M
ICAM (Instituto de Ciências Agrárias Mediterrânicas), Universidade de Evora, Portugal.
Branco
C
C
Soares
R
R
Alho
L
L
Carvalho
M D E
MD
Oliveira
S
S
D029863:Cicer / Q000254:growth & development / Q000382:microbiology*; D016172:DNA Fingerprinting; D014644:Genetic Variation; D010641:Phenotype; D010957:Plasmids / Q000235:genetics; D011174:Portugal; D012231:Rhizobium / Q000145:classification* / Q000235:genetics*; D012287:Rickettsiaceae / Q000145:classification / Q000235:genetics