The optimum flow rate of nutrient solution in hydroponic system can better nourish the crops, allowing healthy and faster growth of lettuce. However, flow also interferes with electric power consumption, so further researches are necessary, mainly on the effect of flow rate, nutrient accumulation and lettuce production. In this context, the aim of this study was to evaluate nutrition and production of head lettuce in relation to the nutrient solution flow in NFT hydroponic system. The treatments consisted of nutrient solution application at the flow rates 0.5; 1; 2, and 4 liters per minute in each cultivation channel. Five replicates per treatment consisted of 15 plants each. The flow in hydroponic systems to produce head lettuce alters the technical performance of the crop. Due to the greater nutrient accumulation in shoot and use efficiency of these elements, the highest production (g/plant) of head lettuce was obtained with a flow rate of 1 L/min of the nutrient solution.

RESUMOO tripes do prateamento, Enneothrips flavens Moulton, 1941, é considerado a principal praga do amendoim no Brasil, por sua ocorrência generalizada, pelos elevados níveis populacionais e pelos danos causados a cultura. Objetivou-se, com este trabalho, avaliar o efeito do silício sobre a população de E. flavens e sobre a produtividade do amendoinzeiro. Avaliaram-se, semanalmente, 10 folíolos abertos ou semi-abertos no terço superior das plantas do cultivar IAC 886, por parcela. Os tratamentos foram constituídos por: uma aplicação foliar de silício realizada aos 20 dias após a emergência, duas aplicações foliares de silício realizadas aos 20 e 55 dias, e o controle. Uma aplicação de silício proporcionou proteção às plantas de amendoim, reduzindo o número de adultos e ninfas do tripes de E. flavens e aumentou a produtividade da cultura em 31,30% de amendoim em casca e 28,85% em grãos.Termos para indexação: Proteção de plantas, resistência induzida, táticas alternativas, amendoim. ABSTRACTThe silvering thrips, Enneothrips flavens Moulton, 1941 is considered the major pest on peanuts in Brazil, due to its widespread occurrence, high population levels, and high damage to the crop. The objective of this study was to evaluate the effect of silicon on E. flavens populations and on peanuts yield. Ten fully-opened or semi-opened leaflets per plant were sampled weekly from the peanut cultivar IAC 886. The following treatments were tested: leaf spraying of silicon at 20 days after plant emergence, two leaf spraying of silicon at 20 and 55 days, and the control check. A single silicon spraying provided protection to peanut by reducing the number of E. flavens adults and nymphs and by increasing the yield of peanut pods by 31.30% and peanut grains by 28.85%.

This research evaluated protected environment and substrates for jatoba seedling. Two protected environments were used: (i) black shading screen on the sides and roof; and, (ii) black shading screen on the sides and thermal-reflective aluminized screen on the roof. In each environment the following substrates formulated with cattle manure (M) and vermiculite (V) were tested: 100% M; 90% M + 10% V; 80% M + 20% V; 70% M + 30% V; 60% M +40% V; 50% M + 50% V; 40% M +60% V; 30% M + 70% V; 20% M + 80% V; 10% M + 90%V. The environment protected with black shading screen was more favorable for the formation of jatoba seedlings, resulting in seedlings with higher shoot height and root collar diameter and, therefore, higher quality. Recommendation is to use substrates containing up to 30% of cattle manure to produce high quality jatoba seedlings.

Genetic and phenotypic parameters of fork (BIF), stem form (RET) and diameter at breast height (DBH) for Dipteryx alata provenances and progenies were assessed. The trial was lead in a randomized block design, with 43 treatments (26 and 17 progenies from the municipalities of Três Lagoas and Brasília in the state of Mato Grosso do Sul and Distrito Federal, Brazil, respectively) and five plants per plot. The spacing between plants was 3 x 3 meters. The data analysis was performed using the REML/BLUP method (restricted maximum likelihood best linear unbiased prediction). Significant differences were detected between progenies only for DBH. The individual genetic values ranged from 3.7 to 21.7 % for BIF and DBH; genetic variation among progenies ranged from 9 to 10.5 % for BIF and DBH among provenances. Individual heritability in the strict sense was high for DBH (minimum from 0.31), revealing the potential for genetic improvement. Provenance and progenies trial showed genetic variability which can be exploited in forest improvement programs with a broad genetic base.

No abstract