Inheritance of self-And graft-incompatibility traits in an F 1 apricot progeny

Floral self-incompatibility affecting yearly yield in a weather-dependent manner and graft incompatibility affecting longevity of mature trees are two important traits for apricot production. However, genetic control of graft compatibility and relationship between these traits are unknown. Here, we analyzed its inheritance in an F 1 apricot progeny from a cross between self- and graft- incompatible and self- and graft-compatible cultivars. Hybrid individuals were genotyped for establishing self-incompatibility status and grafted on the plum rootstock ‘Marianna 2624’. Phenotyping of graft incompatibility was done at two time points, one month and one year after grafting. Anatomical (necrotic layer, bark and wood discontinuity for two consecutive years) and cytomorphological (cell proliferation, cell arrangement and cell shape one month after grafting) characteristics related to graft compatibility displayed continuous variation within the progeny, suggesting a polygenic inheritance. Using the Pearson correlation test, strong and significant correlations were detected between anatomical and cytomorphological traits that may reduce the number of characters for screening genotypes or progenies for graft compatibility in segregating crosses. Furthermore, no correlation existed between self- and graft incompatibility traits suggesting that they are independent inheritance traits. Hence, screening an extended hybrid population is required for pyramiding these traits in breeding programs

Sugar content and organic acid profiles of local apple cultivars recovered from mountain zones

Ancient apple cultivars grown in local areas have so far been largely unexplored and may attract a large share of consumers oriented towards natural foods evoking ancient flavors. In this work, 34 traditional apple cultivars of the Pyrenees were analyzed in terms of sugar and acidity profile and their relation, as alternative fruits for a growing demand in society regarding quality and nutritional proper-ties. The results show a wide range between cultivars of analyzed variables, especially in terms of acid, pH and soluble solids, with high standard deviation values. The results were higher than in other similar studies of commercial apple cultivars, as well as higher values related to other local accessions. The large differences between cultivars can be attributed to the origin of the plant material, since all cultivars were grown under the same geographical conditions and with the same applied agronomic practices. The associations found in this study provide information about the nutritional content of the analyzed apples and their organoleptic and physicochemical qualities, and could be useful in targeting specific consumer requirements. In conclusion, this study highlights the suitability of these local accessions recovered in the Pyrenees as key genetic resources to be used in future breeding programs, as well as its potential use for different products which would open the door to new varieties and new consumption alternatives

Dos aspectos del ciclo del nitrógeno fijación biológica y emisión de óxido nitroso

En esta tesis se exploran dos aspectos del ciclo del N en suelos agrícolas en Uruguay: la entrada de N al ecosistema vía fijación biológica y la pérdida como N2O. El Capítulo 3 trata sobre la fijación biológica en la simbiosis rizobio-Lotus. Se buscó establecer el tipo de rizobios que nodula L. subbiflorus y L. corniculatus, cuál es su diversidad y si esta se modifica frente a un estrés ambiental. Se evidenció gran diversidad entre los rizobios del género Mesorhizobium que nodulan Lotus corniculatus. La cepa usada como inoculante comercial no se recuperó de nódulos de plantas instaladas en praderas con historia de inoculación, pero los genes simbióticos de los aislamientos de los nódulos y el inoculante comercial son similares. Estos rizobios no presentan características de desnitrificantes, mientras que los Bradyrhizobium que nodulan L. uliginosus y L. subbiflorus sí. El Capítulo 4 trata sobre cianobacterias con heterocistos en arrozales. Las preguntas a responder fueron cuáles son los géneros de estas cianobacterias en un suelo de arrozal en rotación con pasturas, y cómo varían a lo largo del ciclo del cultivo. También se evaluó cuánto N2 fijan, si es suficiente el tiempo del cultivo para que su N se mineralice y si la inoculación con cianobacterias aporta N al arroz. Finalmente, se intentó comprender cómo afecta a la fijación el agregado de fertilizante, herbicidas y la luz UV-B. Se concluyó que en vida libre las cianobacterias no son una fuente significativa de nitrógeno para el arroz, si bien su mineralización ocurre durante el ciclo del cultivo. El Capítulo 5 aporta los primeros datos de mediciones de emisiones de gases de efecto invernadero por agrosistemas en Uruguay. Se buscó responder si es diferente la cantidad de N2O emitido por cultivos agrícolas, praderas y campo natural, y si es afectada por las rotaciones y el laboreo del suelo. En el caso de arroz, se intentó establecer cuál es en nuestras condiciones el potencial de calentamiento global y si puede reducirse con el manejo del riego. No se evidenciaron diferencias consistentes en el N2O emitido por agricultura continua o rotaciones, ni entre laboreo convencional y siembra directa. En el cultivo de arroz, las emisiones de CH4 son mayores que las de N2O y el control del agua de riego permitió mitigar las emisiones totales, pero puede disminuir el rendimiento del arroz.This thesis explores two aspects of the N cycle in agricultural soils of Uruguay, N inputs via biological fixation and its losses as N2O. In Chapter 3, where biological nitrogen fixation by rhizobia in symbiosis with Lotus was studied, the aim was to determine the type of rhizobia that nodulate L. subbiflorus and L. corniculatus, their capacity to denitrify and if their diversity was influenced by the environmental conditions. Rhizobia nodulating Lotus corniculatus of the genus Mesorhizobium were highly diverse. The commercial inoculant for L. corniculatus could not be isolated from nodules of plants from pastures with previous history of inoculation, but isolates from nodules and the commercial inoculant shared similar symbiotic genes. These rhizobia did not show characteristic of denitrifiers while bradyrhizobia nodulating L. uliginosus and L. subbiflorus did. Chapter 4 focuses on heterocystous cyanobacteria isolated from Uruguayan ricefields. The goal was to know the most abundant genus of cyanobacteria present in a ricefield in rotation with pastures and how they fluctuate along the rice cycle. How much N2 was fixed, if the N in cyanobacteria was mineralized during the rice cycle and if cyanobacterial inoculation contribute with N uptake by rice, were analstudied. The effects on nitrogen fixation of fertilizer addition, herbicides and UV-B radiation were also evaluated. It was concluded that free living cyanobacteria were not a significant nitrogen source for rice. Instead, mineralization of cyanobacteria occurred quickly during the culture cycle. Chapter 5 contributed with the first data of greenhouse gases emissions in Uruguayan agrosystems. The hypothesis was that crops and pastures emit different amounts of N and are affected by rotations and tillage. The global warming potential for rice in our conditions was estimated and potential mitigation by irrigation control was evaluated. Consistent differences in N2O emission among treatments of continuous agriculture versus rotations or conventional tillage vs no-till could not be proved. In rice systems CH4 emissions are higher than N2O. A mitigation strategy reducing irrigation decreased emissions but may also diminish rice yield

Caracterización de la compatibilidad de injerto en una población intraespecífica de albaricoquero (abstract)

La información genética acerca del carácter de compatibilidad de injerto actualmente no se conoce en profundidad. En este trabajo se ha estimado Ja heredabilidad del carácter de compatibilidad utilizando w1a población de albaricoquero resultante del cruzamiento entre una variedad compatible al injerto ' Paviot' y una variedad incompatible 'Moniquí'. J 1 O individuos de la descendencia Fl se injertaron sobre el patrón 'Mariana 2624' y se fenotiparon mediante observaciones internas evaluando diferentes caracteres relacionados con la compatibilidad de injerto: línea necrótica, discontinuidad de la madera y discontinuidad en la corteza. Asimismo, se ha realizado un análisis complementario de autocompatibilidad floral mediante PCR. En los análisis realizados de las características internas observadas, las más relevantes fueron la necrosis y la discontinuidad en la corteza. Los resultados también sugieren que la compatibilidad patrón-variedad no se correlaciona con la autocompatibilidad floralPublishe

Molecular and physiological bases of the rootsctock-scion interaction in fruit trees [abstract]

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Differential expression of copper/zinc superoxide dismutase in pear/quince combinations during early stages of development: abstract

PublishedPoster number 6

Evaluación del comportamiento vegetativo y compatibilidad de injerto de variedades de peral sobre los patrones ‘BA-29’y ‘OHF-87’

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Early detection of graft incompatibility in an apricot intraspecific population (abstract)

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