Azospirillum spp. have shown potential to enhance nodulation and plant growth of legumes when coinoculated with Rhizobium. The effect of Azospirillum on the Rhizobium-legume symbiosis is, however, dependent on the host genotype used. Previous greenhouse experiments identified two genotypes of common bean (Phaseolus vulgaris L.), BAT477 and DOR364, contrasting in nodulation response to Azospirillum when coinoculated with Rhizobium. Genetic analysis revealed a genetic basis (Quantitative Trait Loci) on the bean genome related to the differential responsiveness to Azospirillum between the two bean genotypes. In this study, on-station and on-farm field experiments in different regions in Cuba were conducted to evaluate the agronomic relevance of the differences in response to Azospirillum-Rhizobium coinoculation between the two genotypes BAT477 and DOR364. It was observed that Azospirillum-Rhizobium coinoculation as compared to single Rhizobium inoculation increased the amount of fixed nitrogen and the yield of DOR364 across all sites. For BAT477, on the contrary, a negative effect of Azospirillum-Rhizobium coinoculation on yield and nitrogen fixation was observed on most of the sites as compared to single Rhizobium inoculation. The modified stability regression equations resulting from this study may contribute to predict how a combination of genotype and inoculum will perform at a certain environmental setting. This study highlights the importance of genotype × inocula interactions in agricultural outputs and establishes a link between greenhouse Plant Soil (2008) 312:25-37 phenotype, genetic background and performance in the field.

The prevalence of incidental findings in the sample studied was high, and the structures most commonly involved were the maxillary sinuses. The results suggest that both the presence and the number of findings per patient increase with age but there is no association with sex.

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difference in the short-term response of nitrogenase activity (C_2H_2 reduction) to salinity and oxygen in the common bean. Agronomie, EDP Sciences, 2001, 21 (6- Abstract -Four genotypes of common bean (Phaseolus vulgaris L.) differing in seed color, were grown hydroponically in a growth chamber to study the short-term effects of 0.1 M NaCl on their symbiotic acetylene reducing activity (ARA). For all genotypes, the ARA was reduced dramatically during the first hour following NaCl application. This was followed by a slower decrease during the next 5 h during which genotypical differences in response to salinity were found. When expressed as percent of the control, the redseed genotype was significantly less inhibited by NaCl than the three others. For all genotypes, the increase in ARA after raising rhizosphere pO 2 was affected by the NaCl treatment. With NaCl the red-seed genotype showed the highest stimulation by pO 2 , which was associated with its higher tolerance to NaCl application. However for all genotypes, raising pO 2 did not allow a complete recovery from the NaCl effect. It is concluded that nitrogenase inhibition by NaCl application in common bean varies among genotypes, and is associated with a short-term nodule limitation by O 2 diffusion, although other mechanisms may also be involved in nodule inhibition by NaCl. N 2 fixation / oxygen diffusion / Phaseolus vulgaris / Rhizobium / salinity Résumé -Effets à court terme de la salinité sur l'activité nitrogénase nodulaire et sa réponse à l'oxygène chez le haricot. Quatre génotypes de haricot (Phaseolus vulgaris L.) différant par la couleur des téguments de leur graine, ont été cultivés hydroponiquement en chambre de culture afin d'étudier les effets de NaCl sur leur fixation symbiotique d'azote et leur croissance. L'activité réductrice de l'acétylène (ARA) était fortement réduite pendant la première heure suivant l'application de NaCl. Cette baisse initiale était suivie d'une baisse plus lente durant laquelle des différences variétales ont été mesurées. Le génotype R était significativement moins inhibé par NaCl que les 3 autres. Pour tous les génotypes, la stimulation d'ARA par augmentation de la pO 2 rhizosphérique était modifiée par le traitement salin. Avec NaCl, le génotype R présenta la plus forte stimulation par la pO 2 , qui était associée à sa plus forte tolérance à NaCl. Toutefois quel que soit le génotype, l'élévation de pO 2 ne compensa pas totalement l'inhibition par NaCl. Il est conclu que l'inhibition de la nitrogénase par la salinité chez le haricot fixateur d'azote varie entre génotypes, et est associée à une limitation du métabolisme nodulaire par un manque d'O 2 , bien que d'autres mécanismes d'inhibition par NaCl puissent être impliqués.

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