Molecular characterization of doubled haploid lines derived from different cycles of the Iowa Stiff Stalk Synthetic (BSSS) maize population.

Molecular characterization of a given set of maize germplasm could be useful for understanding the use of the assembled germplasm for further improvement in a breeding program, such as analyzing genetic diversity, selecting a parental line, assigning heterotic groups, creating a core set of germplasm and/or performing association analysis for traits of interest. In this study, we used single nucleotide polymorphism (SNP) markers to assess the genetic variability in a set of doubled haploid (DH) lines derived from the unselected Iowa Stiff Stalk Synthetic (BSSS) maize population, denoted as C0 (BSSS(R)C0), the seventeenth cycle of reciprocal recurrent selection in BSSS (BSSS(R)C17), denoted as C17 and the cross between BSSS(R)C0 and BSSS(R)C17 denoted as C0/C17. With the aim to explore if we have potentially lost diversity from C0 to C17 derived DH lines and observe whether useful genetic variation in C0 was left behind during the selection process since C0 could be a reservoir of genetic diversity that could be untapped using DH technology. Additionally, we quantify the contribution of the BSSS progenitors in each set of DH lines. The molecular characterization analysis confirmed the apparent separation and the loss of genetic variability from C0 to C17 through the recurrent selection process. Which was observed by the degree of differentiation between the C0_DHL versus C17_DHL groups by Wright's F-statistics (FST). Similarly for the population structure based on principal component analysis (PCA) revealed a clear separation among groups of DH lines. Some of the progenitors had a higher genetic contribution in C0 compared with C0/C17 and C17 derived DH lines. Although genetic drift can explain most of the genetic structure genome-wide, phenotypic data provide evidence that selection has altered favorable allele frequencies in the BSSS maize population through the reciprocal recurrent selection program.

The irrigation effect on nuts' growth and yield of Carya illinoinensis.

Pecan trees require adequate soil moisture conditions to produce nuts with good yield and quality. Irrigation should be an important considered practice in orchards management plan, mainly in regions with water deficit periods. The objective of this research was to evaluate irrigation on pecan nuts growth and yield. This study was conducted in Uruguay, during the fast development phase until the pecan nuts harvest. Three irrigation treatments were used: 0 L (control), 70 L and 140 L plant-1 of water every two days, applied via drip irrigation in seven-year-old pecan trees of the cultivar Success. The number of nuts per cluster and nuts' diameter and length were evaluated during nut growth. After harvesting, peeled nuts' width and length were measured, and after peeling, the kernel length, width, height and filling and the kernel and peel percentage were evaluated. According to the results, it was possible to identify that periods of water deficit during pecan nuts development affected the kernel filling stageand size. Irrigation in pecan plants provides greater dimensions and nuts mass. With the use of 140 L plant-1, there was an increase in the nut mass of more than 100% in relation to the nuts from plants without irrigation.

Physicochemical characterization of fruits of Campomanesia guazumifolia (Cambess.) O. Berg (Myrtaceae)

Belonging to the family Myrtaceae, ‘sete capotes’ is a plant native to the Atlantic Forest biome. It produces yellow-green fruits between February and May. Although used for consumption by local populations, studies of the fruit are rare. The present work aimed at characterize the fruit in terms of physicochemical properties. We quantified mass, volume, moisture, pulp yield, pH, titratable acidity, soluble solids/titratable acidity, proteins, lipids, total sugars, reducing sugars, ash, macronutrients, micronutrients, pectin, vitamin C and phenolic compounds. Compared with commercial fruits and other native fruit trees, sete capotes is unusual for its pulp yield, vitamin C levels, total phenolic compound content, protein levels, calcium content, potassium levels and iron content. Through the results it is verified of the fruit as a functional food, mainly because of its nutritive content and because of its bioactive compounds. Our data emphasize the importance of study of the constituents of native flora.

Management of pruning and evaluation in blackberry cultivars in relation to productive characteristics and bioactive compounds.

The goal of this work was to evaluate blackberry cultivars in terms of productivity and bioactive compounds. Two experiments were conducted: in the first experiment four cultivars were evaluated (Cherokee, Guarani, BRS-Tupy and Xavante). In the second experiment, the effects of pruning management in the BRS-Tupy cultivar were evaluated with the following treatments: drastic winter pruning (zero primocane), and maintenance of two, three or four primocanes in the winter pruning. Vegetative, productive and fruit quality characteristics were determined, including measurement of bioactive compounds. Among the cultivars, the cultivar BRS-Tupy was superior in terms of productive characteristics, but for content of anthocyanins and flavonoids, the cultivar Xavante stood out (191.97 and 68.44 mg 100 g-1, respectively). Drastic winter pruning produced lower fruit quality. The number of primocanes has a directly proportional influence on the soluble solids content and productivity component. For farmers who want fruits with greater levels of bioactive compounds, the use of cultivar Xavante is recommended; however, for those who aim for productive aspects, we suggest the use of cultivar BRS-Tupy with four primocanes per plant.