Abstract: The objective of this work was to compare distributions for the modeling of the number and dry matter weight of nodules (DWN) of Rhizobium from different inoculants in common bean (Phaseolus vulgaris) inbred lines subjected to nitrogen doses, as well as to identify the best inoculant for those lines. The experiment was carried out in a randomized complete block design, arranged in split-split plots, with three factors – four inbred lines, five nitrogen doses (0, 20, 40, 60, and 80 kg ha-1), and three inoculants (CIAT 899, UFLA 02-100, and peat) – and four replicates. The number of nodules and their dry matter weight were analyzed with the generalized linear mixed modeling approach. The highest number of nodules was obtained with the CIAT 899 inoculant, at the dose of 20 kg ha-1 N (260 nodules), followed by UFLA 02-100, at 80 kg ha-1 (109 nodules), and peat alone at 20 kg ha-1 (98 nodules). The DWN with CIAT 899 exceeded in 0.66 g the DWN with UFLA 02-100, and in 0.95 g the DWN obtained without inoculation (inoculated with peat alone). The use of the negative binomial distribution and of the gamma distribution is a simple way to control data overdispersion of the nodule number and data underdispersion of DWN, respectively.

NA

Chile is one of the principal producer and exporter country of fruit and vegetable crops in the southern
hemisphere. In both fruit and vegetable crops there are an increasing concern about agriculture sustainability
that includes the evaluation and implementation of practices with lower environmental impact. In this
context, and considering the modern vegetable crop production, the use of rootstocks is being considered an
essential component due to their ability to adapt a particular cultivar to diverse environmental conditions
and/or cultural practices.
In agriculture, rootstocks have been used since over 2000 years ago. Specifically, in cucurbits, the most
grafted vegetable crops are watermelon, melon and cucumber. For watermelon, Lagenaria siceraria (bottle
gourd) has been used in different countries as one of the main rootstocks. Considering the recent agricultural
scenario, in which drought represent the major risk that impacts negatively the production of major and
minor crops, the rootstocks development and the understanding of the role of key root traits would help to
assist breeders for drought tolerance landraces selection. In fact, the effects of water regime or deficit on
root system development of bottle gourd is not well understood, in addition, the underlying phenotypic and
genotypic variability of bottle gourd with respect to root system architecture parameters has not been welldocumented.
A crucial component of roots is their architecture, which refers to the spatial-temporal extension of the entire
root system in the soil, the root system architecture (RSA). RSA traits, or phenes, has been shown to be
important in agricultural systems, in fact, it is considered relevant for improve selection in fruit and vegetable
rootstocks breeding programs. Understanding the contribution of specific RSA traits to root system function
is critical, and plays a pivotal role in crop performance because it allows the identification of keys traits that
contribute in desired functions, and consequently could be considered for developing crops with more efficient
roots.
In this proposal it is hypothesized that, landraces of Lagenaria siceraria shows high phenotypic and genotypic
variation for RSA traits like Root Growth Angle (RGA) and Roots System Depth (RSD). In turn, these phenes
are positively correlated with drought tolerance and therefore useful to develop rootstocks with this
characteristic in Lagenaria siceraria. In addition, it is also hypothesized that selected L. siceraria rootstocks
are able to confer to grafted varieties of watermelon (Citrullus lanatus) an enhanced tolerance to drought.
For that, the main goal is to evaluate the root system architecture as parameter of selection for drought
tolerance in different Lagenaria siceraria landraces and in grafted plants of watermelon (Citrullus lanatus).
The specific goals are: 1. To assess the phenotypic and genotypic variation of Lagenaria siceraria landraces
by using root system architecture parameters and genotyping-by-sequencing through SNP markers; 2. To
determine the root system architecture parameters that help into the selection of Lagenaria siceraria under
drought stress condition; 3. To characterize the response to drought stress of watermelon grafted onto
Lagenaria siceraria landraces under field conditions after the selection through the root system architecture
parameters.
To reach this goals it is proposing the phenotypic characterization of root traits (phenes) in Lagenaria siceraria
landraces in a greenhouse under drought stress condition. The genotypic variation of bottle gourd will be
studied by using Genotyping-by-sequencing, principal component analysis and genetic relatedness (identityby-state). A multivariate statistical analysis will be implemented to select key root phenes which will be used
to evaluate the selection of L. siceraria in a rootstock breeding program. These root phenes will be
characterized in grafted plants of watermelon into L. siceraria under field conditions by using the shovelomics
phenotyping method.
This proposal expects to contribute with the knowledge of genotypic and phenotypic variation in bottle gourd
for root system architecture traits, and to identify the possibilities that offers the key root phenes to screen
rootstocks for drought tolerance. These results would be relevant for the selection and breeding of cucurbits
rootstock with better tolerance to drought. It is also expected that some of these Lagenaria siceraria
landraces will be important rootstock for watermelon under semi-arid conditions of Chile.

Doble afiliación por contrato a medio tiempo Instituciones UOH y CEAF

Downy mildew caused by Plasmopara viticola is a major disease of grapes in Paraná State, Brazil and other wine-producing regions. The seedless table grape ‘BRS Vitória’ stands out for its tolerance to this disease and is a viable alternative to reduce fungicide applications. The objectives of this study were to analyze the influence of weather-related factors, such as temperature and rainfall on disease progress and to evaluate the efficacy of fungicide spray programs for controlling downy mildew of grapes during the summer-fall and winter-spring crop seasons in northern Paraná, Brazil. Field trials were conducted in Marialva, Paraná, during the winter-spring crop seasons (August to December) in 2013 and 2014 and the summer-fall crop seasons (January to May) in 2014 and 2015. The experimental design used was completely randomized with repeated measurements over the phenological periods, with five treatments and 10 replicates. The following treatments were compared: (1) conventional, in which fungicides were applied according to conventional standards; (2) preventive fungicide sprays every seven days; (3) preventive fungicide sprays every 14 days; (4) fungicide sprays after observing the first downy mildew symptoms; and (5) no fungicide sprays. In the conventional fungicide program, sprays were performed two or three times per week. Treatments 2 and 3 received sprayings between the start of branch budding and fruit ripening. In treatment 4, sprays started from the first occurrence of oil spot symptoms, and then, the applications were spaced every seven days until fruit ripening. The severity of disease was evaluated weekly. The disease was severe only in the 2014 and 2015 summer-fall crop seasons, reaching a maximum severity of 17.3% and 21.3% of the leaf area, respectively. The highest disease severity in the summer-fall crop seasons was associated with higher frequencies of rainy days and higher temperatures. Disease severity in conventional treatments did not differ from severity in treatments with sprayings made every seven and 14 days during the summer-fall crops in both years. Severity index on bunches were not observed for the evaluated trials. The seedless grape ‘BRS Vitória’ is less dependent on the use of fungicides to control downy mildew in northern Paraná.