Cultivo de nueve variedades de sandía bajo condiciones edafoclimáticas de la Sabana brasilera: Variables morfológicas, características fisicoquímicas y vida útil de frutos Cultivation of nine varieties of watermelon under edaphoclimatic conditions of the Brazilian Savannah: Morphological variables, physicochemical characteristics and useful life of fruits

Quality seedlings production is one of the most important steps in the cultivation of vegetable species. In this sense, the objective was to evaluate the influence of different environments and substrates on the production of “pimenta-de-cheiro” (Capsicum chinense Jacq.) seedlings in Boa Vista, Roraima. An experiment was installed in a completely randomized design (CRD), with treatmentsarranged in subdivided plots. Five environments were evaluated: AG - agricultural greenhouse; TV35 - red shading net with 35% shading (red ChromatiNet®); TV50 - red shading net with 50% shading (red ChromatiNet®); TP35 - silver shading net with 35% shading (ChromatiNet® silver) and TP50 - silver shading net with 50% shading (ChromatiNet® silver) and four substrates: O -OrganoAmazon®; OP - OrganoAmazon® and PuroHumus®; OPSE (OrganoAmazon®, PuroHumus®, soil and manure) and OPSEC (OrganoAmazon®, PuroHumus®, soil, manure and carbonized rice husk). On the TP35 and TP50 shading nets, the C. Chinense grown on the OP substrate showed high Dickson’s quality index (DQI). The combination agricultural greenhouse (EA) and OPSE substrate promoted superior quality Capsicum chinense seedlings. The substrates OPSEC and OPSE are more affordable alternatives for the production of Capsicum chinense seedlings. Shading nets, associated with the alternative substrates, do not favor the production of quality Capsicum chinense seedlings under Amazon savanna conditions.

With the aim of increasing the production of Croton lechleri Mull.Arg plants due to its attributes as a medicinal plant, the effect of different types of stakes and substrates as root promoters under intermittent nebulization conditions was evaluated. The work was conducted through a randomized complete block scheme adapting a factorial of 4 × 3, being the factors types of stakes (apical with leaves, apical without leaves, medium and basal) and substrates (sand, sand + Aserrin (1:1) and Aserrin (100%) at the rate of 10 stakes per repetition totaling 360 stakes throughout the experiment. The percentage of root (%), dead stakes (%), sprouted stakes (%), dead stake diameter was evaluated. (mm), shoot length (cm) and root length (cm) The Aserrin provided the highest number of dead stakes and the smallest number of shoots in the species, with apical stakes with leaves and the combination of sand + Aserrin as a substrate providing the highest percentage of roots formed, therefore these two factors influence the production of plants in the dragon blood species.

Adenium obesum (Forssk.) Roem. & Schult., widely known as desert rose, has attracted interest for its esthetic characteristics, which are influenced by the process of seedling production. Using two consecutive experiments installed fully at random, the study aimed at assessing the use of different substrates and hydrogel to produce desert rose seedlings in a protected environment. First, eleven substrates were tested, prepared as follows: OrganoAmazon®; PuroHumus®; soil; rice husk in natura; carbonized rice husk, sawdust and cattle manure. Then, three substrates were tested (S1 - OrganoAmazon® + PuroHumus®; S2 - OrganoAmazon® + PuroHumus® + rice husk in natura and S3 - OrganoAmazon® + PuroHumus® + carbonized rice husk) associated to four hydrogel levels: 0 (daily irrigation), 1, 2 and 3 g L−1 (irrigated on alternate days). Growth variables and quality index of seedlings were assessed. Six substrates (all of them without addition of sawdust and where used in mix) were grouped as those the promoted appropriate growth of seedlings, with height, number of leaves, collar diameter, root length and aerial part biomass superior to 6.5 cm; 13; 12 mm; 7.5 cm and 0.45 g, respectively. The substrate composed of OrganoAmazon® + PuroHumus® (1:1 v/v), when irrigated daily, was the one that favored most the production of quality seedlings. The use of hydrogel in substrates with shifts of irrigation on alternate days did not favor the production of desert rose seedlings.

Camu-camu (Myrciaria dubia), a fruit from the Amazon region, has received attention due to its high content of antioxidant compounds such as ascorbic acid and polyphenols. This study’s objective was to select camu-camu clones according to their morphological characteristics using multivariate analyses. We evaluated 56 camu-camu clones distributed in three blocks with two plants per experimental plot. The variables measured were plant height (H), number of basal branches (NBB), number of terminal buds (NTB), basal stem diameter (BSD), chlorophylls a (Chl a) and b (Chl b), and total chlorophyll (Chl a + b). Principal component (PCA) and multivariate clustering analyses were performed using the average linkage mean and Mahalanobis distance algorithms. After 24 months, results showed that the characteristic that least contributed to clone selection was NBB. The plant height (H), number of terminal buds (NTB), basal stem diameter (BSD), chlorophylls a (Chl a) and b (Chl b), and total chlorophyll (Chl a + b) had the most positive contribution towards the initial selection of camu-camu clones at two years of age. The 22 camu-camu clones showed the highest rate of vegetative development or vegetative quality index (VQI) in the transitional savanna/forest area of the northern Amazon, Brazil, after two years of transplanting.