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R. A. de-Sales, and A.H. de Oliveira-Carvalho. 2020. Yacon potato propagation from herbaceous cuttings with different numbers of buds. Int. J. Agric. Nat. Resour. The objective of this study was to evaluate yacon potato propagation from herbaceous cuttings with different numbers of buds. Therefore, an experiment was carried out in two phases. The first phase was carried out in a greenhouse with seedlings using a randomized complete block design with 40 replicates. The treatments consisted of varying the number of buds per cutting: two buds (T1), three buds (T2), or four buds (T3). The second phase was carried out in the field following a randomized complete block design with 4 replicates, and the treatments were the same as those used in the seedling phase. The following morphological characteristics were evaluated: number of leaves per plant, leaf area, plant height, stem diameter, number of stems per plant, leaf dry mass, stems, rhizophores, tuberous roots, and tuberous root yield. The physiological characteristics evaluated were the relative chlorophyll content (FCI-Falker chlorophyll index), net CO 2 assimilation rate, leaf transpiration, stomatal conductance, internal CO 2 concentration, water use efficiency and instantaneous carboxylation efficiency. It was observed that the seedlings from cuttings with 3 buds presented higher stomatal conductance (g s), which reflected their higher transpiration rates. The yacon potato presented the best vegetative and productive development when propagated by herbaceous cuttings with three buds.

Yacon (Smallanthus sonchifolius [Poepp.] H. Rob., Asteraceae) is an Andean plant being explored as a functional food, due to high concentrations of fructooligosaccharides (FOS), a natural sweetener capable of reducing blood lipids and glucose levels, supporting prevention of chronic diseases, such as diabetes. Yacon commercial production is still being established, thus cropping practices and their impact on profitability are yet poorly explained. Improved planting recommendations are demanded, as it affects crop yield. In this background, a field trial was conducted to determine row spacing and plant populations for yacon production in tropical highland areas. The experimental design was a randomized complete block, in a split-plot scheme, where blocks were three row spacings (0.8, 1.0 and 1.2 m) and subplots covered three spacings between plants (0.4, 0.5 and 0.6 m), with four replicates. At harvest time, evaluations on accumulation of dry mass in the plant and tuber root production data (number, weight, total productivity, and per class) were made. Profitability indicators were estimated (gross income, operational profit, and benefit-cost ratio). Data suggest productive and economic variations among tested planting configurations, as an example higher productivity (31.5 t ha -1 ) and positive benefit-cost ratio (2.51) when using 1.0 m between rows and 0.4 m between plants for the conditions tested. These results point out the prospect to select better crop management practices for yacon, cutting costs, and increasing yield. Another key find was yacon's capacity to overcome intense drought and temperature stress, not previously documented for this crop. Therefore, yacon is a new crop with potential to boost farming income through crop diversification.

The consumption of yacon has been increasing around the world due to the nutritional and pharmaceutical properties of this plant. The growing commercial interest in yacon (Smallanthus sonchifolius) generates a demand for crop management research studies, including the effect of weed competition on yacon, which was not yet studied. Thus, this study was performed with the objective of evaluating the effects of weed competition on yacon development and growth. The experimental design was completely randomized with four treatments and seven replicates. Treatments were yacon with the interference of four weed species: Cyperus rotundus L. (nutgrass), Commelina benghalensis L. (tropical spiderwort), Amaranthus viridis L. (slender amaranth) and Bidens pilosa L. (hairy beggarticks). The experiment was conducted in a greenhouse, using 10 dm3 pots. Plant height, number of leaves, number of stems, leaf area, fresh and dry mass weight (total and partial), and chlorophyll A, B and total were evaluated. The weed competition resulted in a decrease in the yacon development (height, number of leaves, number of stems, leaf area), photosynthetic rate (decreased chlorophyll content A, B and total) and yield, as also decreased the accumulation of fresh and dry biomass of tuberous roots. C. benghalensis L. and A. viridis L. were the weeds most affecting the development and growth of yacon.

The interest in yacon has generated a demand for information that may enhance the production system. Among them are the studies on the different spatial arrangements of planting spacing. Therefore, the purpose of this study was to evaluate the production and yield of yacon cultivated in different arrangements, varying the spaces between the lines and the plants. The experimental design was a randomized complete block design, being the parcels composed by three spacing between lines (0.80, 1.0 and 1.20 meters) and the subplots by three spacing between plants within the lines (0.40, 0.50 and 0.60 meters), distributed in 9 treatments with four replications. At harvest time, evaluations on the accumulation of dry mass in the plant and tuber root production data (number, weight, total productivity, and per class) were made. Profitability indicators were estimated (Gross Income, Operational Profit and Benefit-Cost ratio). The arrangements of 0.80 x 0.40 m and 1.00 x 0.50 m produced higher tuberous roots yield (37.5 and 39.8 t ha-1, respectively), but the arrangement 1.00 x 0. 50 m had a higher profit (US$ 13,854.91) and a better benefit-cost ratio (4.9), which is the most indicted.

The planting of unconventional vegetables has increased in Brazil. This is mainly due to the demand of nutritionally rich foods grown in sustainable crops. In this scenario, ora-pro-nobis stands out, as, although being part of the meal of large part of the Brazilian population, it has been cultivated despite the lack of scientific knowledge. Thus, this study aimed to adjust a leaf area estimation model for ora-pro-nobis, using the measurements of the leaves. For the model adjustment and validation, 4000 leaves were collected in four different genotypes, being 1000 in each of them. The regression models were adjusted using 2000 independent and random observations, using 500 leaves per genotype. Thus, the observed leaf area was studied as a linear function of the dimensions of the leaf blade: length (L), width (W) and product (LW). The remaining 2000 observations, also 500 per separate genotype, were used only in the statistical validation study. The adjusted allometric model based on the product (LW) proved to be precise and accurate for estimating the leaf area of ora-pro-nobis, being applicable to any of the four genotypes analyzed regardless of the leaf size: L A ^ L W = 0.9294 + 0.6815 x L W.

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