Wagner Rodrigues dos Santos

Growth trends, genotype-environment interaction and genetic gains in six-year-old rubber tree clones (Hevea) in São Paulo State, Brazil

Budwood from seven different clones of rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell. Arg.] was planted in replicated trials in four different test sites in the plateau region of the state of Sao Paulo, Brazil. The clones represented a range of imported germplasm, whereas the locations were selected to represent a range of rubber growing areas. Girths were measured for six years consecutively, before the initiation of tapping for latex. Total number of latex vessel rings (lvr) and bark thickness (bt) were measured at six years. The largest average for all characters was observed in Matao. Overall means for girth, total number of latex vessel rings and bark thickness at six years were 35.26 cm, 11.30 units and 4.83 mm, respectively. Both the test sites and clones showed statistically significant differences in girth, lvr and bt values. There were significant clone x site interactions. Girth at one year was not a reliable predictor of future field performance. Broad sense heritability for girth was 0.16, and for lvr and bt it was 0.28 and 0.40, respectively, at six years. Repeatability was quite high, from 0.52 to 0.75 for all characters in all years. When two clones out of seven were selected, expected genetic gain in girth was about 2.0%; for lvr and bt it was 7.0% and 14.6%, respectively.

Diagnose nutricional do cafeeiro pelo DRIS variando-se a constante de sensibilidade dos nutrientes de acordo com a intensidade e freqüência de resposta na produção

O objetivo deste trabalho foi testar a hipotese de usar escores diferenciados para nutrientes irresponsivos (I), medianamente responsivos (M) e responsivos (R), como forma de reduzir os efeitos da interdependencia no calculo dos indices do DRIS (Sistema Integrado de Diagnose e Recomendacao) e seus efeitos na diagnose nutricional do cafeeiro. O trabalho foi desenvolvido usando os resultados do monitoramento nutricional, pela analise foliar, de talhoes de cafeeiros em empresas produtoras situadas nos municipios de Matao e Franca (SP). Os dados foram coletados durante os anos de 1999 a 2001. Os calculos dos indices do DRIS foram feitos usando-se a formula proposta em 1981 por Jones, em sua forma original com uma constante de sensibilidade k = 30 para todas as relacoes entre nutrientes, ou atribuindo diferentes valores para a constante de sensibilidade em funcao da resposta do cafeeiro aos nutrientes. Os resultados, quando avaliados pela relacao entre o indice de balanco nutricional medio (IBNm) e a produtividade, mostraram que a atribuicao de escores diferenciados na ordem I<M<R mostrou maior eficiencia quando comparada ao metodo tradicional de calculo dos indices DRIS. A melhor relacao foi 1-6-10 e a pior, 1-10-1. Na analise comparativa com os diagnosticos obtidos pelo criterio de faixas de suficiencia (CFS) o uso de escores diferenciados para o calculo do DRIS mostrou desempenho ligeiramente superior para as melhores relacoes (I-M-R) quando se compararam as melhores e as piores relacoes, porem os ganhos em relacao ao procedimento tradicional de calculo, cujo peso relativo de todos os nutrientes e o mesmo, foram pequenos, indicando a necessidade de ajustes locais para a diagnose nutricional do cafeeiro pelo criterio de faixas de suficiencia.

Diagnose nutricional para nitrogênio e potássio em bananeira por meio do sistema integrado de diagnose e recomendação (DRIS) e de níveis críticos

The Performance of DRIS and critical value approach (CVA) diagnostics were evaluated based on leaf analysis from a field experiment on a factorial design to study the yield response of banana to N and K applications during two crop seasons. The situations identified as deficient were classified as positives (+) and those diagnosed as sufficient, were classified as negatives (-). According to the response on yield due the application of N or K, the diagnostics were classified as true (V) or false (F). Four combinations were possible: V+, V-, F+ and F-. The efficiency for N diagnostics (%V+ and %V-) based on the critical value approach was 48%, while using the DRIS it was 69%. The efficiency for K diagnostics was 63% for both DRIS and CV methods. The relation between deficient diagnostics confirmed by positive response on yield under application of the nutrient and false positive cases (%V+¸%F+) for N was 1.5 for the DRIS and 0.68 for CVA. For the K deficiency diagnostics, the value of this relation was 1.67 for both methods. The net yield derived from N application based on correct diagnostics (48 cases) was 124 Mg ha-1 for DRIS and 20 Mg ha-1 for the CVA. For K, this variation was 70 Mg ha-1 for the DRIS and the CVA.

Avaliação do estado nutricional da videira 'Itália' na região de São Miguel Arcanjo-SP, utilizando o sistema integrado de diagnose e recomendação

This work aimed to evaluate nutritional condition of Italia grapevine in the region centered in Sao Miguel Arcanjo, SP, Brazil. It was used the Diagnosis and Recommendation Integrated System (DRIS). Twenty bearing vineyards in that region using similar cultural practices were nutritionally surveyed. Leaf blade and petiole samples were taken at three developing phases of grapevine plants: at bloom, in fruits between pea and have-berry and at the beginning of fruit maturation. Leaf blade and petiole samples were analyzed for macronutrients. The reference population used in the calculation of DRIS norms was that of vineyards with average yield between 20.7 to 36.3t/ha. NBI (Nutritional Balance Index) and the sequence of nutrient limitation were individually calculated for each vineyard at three sample phases and for leaf blade and petiole. In this evaluation permitted to conclude that DRIS was a good method for evaluation of nutritional condition of grapevine cv. Italia. Eleven vineyards were considered nutritionally balanced, with average yield between 20.7 to 36.3t/ha. Correlations between NBI and yield indicated that leaf blade sampled at bloom was the better choice. The DRIS allowed the determination of vineyards that usually presented a deficiency of phosphorus, potassium and magnesium.

Responses of rubber tree clone RRIM 600 to NPK fertilization on red yellow podzolic soil

The response of rubber tree [Hevea brasiliensis (Willd. ex. Adr. de Juss.) Muell.Arg.], clone RRIM 600 to NPK fertilization during the immature stage was evaluated on a sand soil at Avai, State of Sao Paulo, Brazil. Randomized block, closing with fractionated factorial experiment 1/2(4 x 4 x 4) was used to test 0, 40, 80 and 120 kg.ha-1 of N, P2O5 and K2O, applied from the second to the eighth years after planting. Trunk girth at 1.20 m above the budgrafting union was measured every four months. The percentage of plants able for tapping and the immaturity period were calculated from girth measurements. Soil analysis were performed at 27 and 51 months after planting and leaf analysis every year. Responses to nitrogen fertilization started to be observed from 60 months, aproximately three years after the beginning of fertilizer applications. Linear effect of phosphorus and NP interaction started at ages of 72 and 75 months respectively. Responses to K fertilization was not detected for trunk girth. Considering the percentage of plants able for tapping, responses were linearly and statistically significant for N and K fertilization. The immaturity period of the crop was reduced eigth months when non fertilized plots were compared to those with the best relations of NPK. Delay of immaturity period up to twelve months was observed considering the best treatments and those with unbalanced relations of NPK. Fertilizer responses disappeared one year after stopping fertilizer applications.

Efeito da adubação NPK sobre o período de imaturidade da seringueira

The purpose of this study was to evaluate the response of rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell. Arg.] to NPK fertilization in order, to improve fertilizer recommendation during the immature phase of this crop. It reports the results obtained from an experiment conducted on a podzolic soil at Matao, State of Sao Paulo, Brazil. It was a randomized block design in a fractionated factorial experiment 1/2(4 x 4 x 4) using 0, 40, 80 and 120 kg.ha-1 of N, P2O5 e K2O. Fertilizers were applied every year starting eight months after planting. During the experimental period evaluations of trunk girth 1.20 m above the budgrafting union was measured at each four months. The percentage of plants able for tapping and the period of immaturity were calculated from girth measurements. Soil and plant analysis were performed at several ages. Plant responses to potassium fertilizations were observed starting at 24 months of plant age. Linear NK interaction was frequently observed after 48 months of plant age. Considering the percentage of plants able for tapping, responses were linearly and statistically significant for K fertilization, while N responses were observed in some ocasions. The immaturity period of the crop was significantly affected only by K fertilizers. Besides of this observation, the analysis of the response surface showed that the immaturity period was very dependent on equilibrated relations among nutrients. Unbalanced relations of NPK can delay up to 15 months the beginning of tapping, considering differences between the best and worst treatments. In the absence of K fertilization there was an antagonistic effect of N and P. Potassium fertilization was essential to reduce the immaturity period.