Antônio Lúcio Mello Martins

Genotype-environment interaction and phenotypic stability for girth growth and rubber yield of Hevea clones in São Paulo State, Brazil

The best-yielding, best vigour and most stable Hevea clones are identified by growing clones in different environments. However, research on the stability in Hevea brasiliensis (Willd. Adr. ex Juss.) Muell.-Arg. is scarce. The objectives of this work were to assess genotype-environment interaction and determine stable genotypes. Stability analysis were performed on results for girth growth and rubber yield of seven clones from five comparative trials conducted over 10 years (girth growth) and four years (rubber yield) in Sao Paulo State, Brazil. Stability was estimated using the Eberhart and Russell (1966) method. Year by location and location variability were the dominant sources of interactions. The stability analysis identified GT 1 and IAN 873 as the most stable clones for girth growth and rubber yield respectively since their regression coefficients were almost the unity (b = 1) and they had one of the lowest deviations from regressions (S2di). Their coefficient of determination (R2) was as high as 89.5% and 89.8% confirming their stability. In contrast, clones such as PB 235, PR 261, and RRIM 701 for girth growth and clones such as GT 1 for rubber yield with regression coefficients greater than one were regarded as sensitive to environment changes.

Variabilidade genética em caracteres morfológicos, agronômicos e citogenéticos de populações de maracujazeiro-doce(Passiflora alata Curtis)

The sweet passion fruit (Passiflora alata Curtis) is polymorphic with high variability in size, shape, weight, thickness of cortex, color of pulp and number of seeds in the fruit. The propagation by seeds increases the heterosis of the cultivated plants. The aim of this paper was to evaluate agronomic, morphological and cytogenetics aspects and identify native population of passion fruit. The introductions Mogi-Guacu and Grande showed better characteristics.

PERFORMANCE OF GINGER GRASS (Lippia alba) FOR TRAITS RELATED TO THE PRODUCTION OF ESSENTIAL OIL

Lippia alba (Verbenaceae) is a shrub whose essential oil has important biological, pharmacological, and aromatizing properties. To reach the sustained cultivation of new species with economic potential, the present study aimed to evaluate L. alba performance for fresh leaf matter (FM), leaf dry matter (DM), virus symptoms (VS - Cucumber mosaic virus, CMV), oil yield (OY), and oil chemical composition (OC), and to evaluate DM stability and adaptability. Ten genotypes of four chemical groups (chemotypes) were evaluated in six experiments designed as randomized blocks with two plants per plot, over the whole State of Sao Paulo, Brazil. A 2.0 x 0.4 x 1.6 m spacing was used in Monte Alegre do Sul and Pindorama, while a 1.0 x 0.4 x 0.6 m spacing was used in Campinas, where four experiments were established under different irrigation and fertilization conditions. The genotype effect was significant (p < 0.05) for all traits evaluated, with high leaf productivity of IAC-16 (citral chemotype), best OY means in the linalool and limonene/carvone chemotypes, and susceptibility of the latter chemotype to CMV. The genotype performance oscillations in the six environments were significant for FM and DM, and despite their significance for phytochemical traits (OY and OC), they were of low magnitude. No qualitative variation was detected for OC. The IAC-2 (linalool) and IAC-13 (limonene/carvone) genotypes showed high stability and wide adaptability, and are recommended to establish initial cultivations of this species. This research also indicated genetic sources to start Lippia alba genetic breeding programs.

Nitrogênio e potássio via fertirrigação e adubação convencional-estado nutricional das bananeiras e produção de frutos

A field experiment was carried out in Pindorama (Sao Paulo State, Brazil) with the objective of investigating the effects of N and K application through fertirrigation and conventional fertilization on banana plants during two crop cycles. Plant growth, nutrition status and fruit production were evaluated. The fertilization caused a reduction in the productive cycle. Fertilizers applied by fertirrigation or conventional fertilization changed the N and K leaf content. The fruit production varied in function of the treatment in the two cultivated cycles. Fruit production (t ha 1 year 1) obtained with application of 80% of N and K doses by fertirrigation was comparable to fruit production with 100% of fertilizer rate applied by conventional fertlization.

Sistemas conservacionistas de manejo do solo para amendoim cultivado em sucessão à cana crua

Field studies were conducted from 2000 to 2005 to evaluate the effects of conservation tillage on agronomic characteristics of two peanut cultivars, cultivated in rotation with sugarcane harvested without burning. Tillage systems included reduced tillage, no-tillage, and conventional tillage, which were arranged in a split-plot randomized complete block design with four replications in two different types of soil, Oxisol and Ultisol, located in Ribeirao Preto and Pindorama cities, SP, Brazil. Tillage treatments were main plots while subplots were peanut genotypes (IAC-Tatu ST and IAC-Caiapo). Results of seven experiments showed no statistic difference on pod yield, kernel yield, number of pods and pegs, between the conservation tillage systems and the conventional tillage, but a decrease on stand of plants can occur. Three out of seven experiments showed a significant interaction between the cultivar and tillage system. The response of different tillage systems for cv. IAC-Caiapo was lower than for cv. IAC-Tatu ST. No-tillage system can show increase (between 6.5 and 9%) on mature kernel rate as well as good or better soil moisture during a dry period.

Stock-scion interactions on growth and rubber yield of Hevea brasiliensis

Rubber tree cultivation [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg.] uses mostly the budding propagation method, however the expected stand uniformity due to the use of vegetative propagation is theoretical, since high variation for yield and vigor is caused by rootstock influence. The objective of this study was to assess several combinations between clonal rootstocks and clone scions through diallel analysis, aiming at high productivity and vigor. Data consisted of five years of dry rubber yield and girth at panel opening from an experiment using a split-plot design with four replications, conducted at Pindorama, SP, Brazil, considering six rootstocks (GT 1, IAN 873, PB 235, RRIM 600, RRIM 701 and unselected seedlings) and six scions (GT 1, IAN 873, PB 235, PR 107, RRIM 600 and RRIM 701). A 6 ´ 6 partial diallel analysis summing up 36 combinations was undertaken, and general compatibility for each group of materials (rootstocks and scions) and specific compatibility among all combinations were estimated. The results have shown that PB 235 and IAN 873 rootstocks provided high yields and general compatibility values (7.9348 and 2.7647, respectively). The use of unselected seedlings as rootstocks is not recommended because they presented very low compatibility values for dry rubber yield. Towards growth vigor, the tested rootstocks have shown similar performance.

Selection and genetic gains for juvenile traits in progenies of Hevea in São Paulo State, Brazil

Five yield traits were investigated in three-year-old progenies from open-pollinated rubber trees [Hevea brasiliensis (Willd. ex Adr. de Juss) Muell.-Arg.]. Twenty progenies were evaluated in a randomized, complete block design replicated three times using 10 plants per linear plot at the North Central Experimental Station in Pindorama, Sao Paulo State, Brazil. The characters evaluated included the average yield of rubber, growth vigor, bark thickness, total number of latex vessel rings and latex vessel size. Highly significant (p < 0.01) genetic differences were observed among progenies for most traits. The genotypic variance components accounted for 13.2%, 12.3%, 9.4%, 3.4% and 0.23% of the phenotypic variance for yield, growth vigor, bark thickness, total number of latex vessel rings and latex vessel size, respectively. Heritabilities, as well as genotypic and phenotypic correlations among traits, were estimated. Heritabilities for the above traits at the individual plant level () were 37%, 35%, 69%, 10% and 16%, respectively. Significant positive genotypic and phenotypic correlations were found between the yield of rubber and growth vigor (rg = 0.73, rp = 0.70), bark thickness (rg = 0.70**, rp = 0.75**) and the total number of latex vessel rings (rg = 0.64, rp = 0.80). There was no relationship between yield and latex vessel size, growth vigor or total number of latex vessel rings. Based on these data, selecting the best two out of 20 progenies would result in a genetic gain of 12.3% and 6.8% for yield of rubber and growth vigor, respectively. The two best individual ortets within each progeny would result in a genetic gain of 27.7% and 9.1%, with a total gain of 40% and 16% for these two traits, respectively.

Nitrogênio e potássio em bananeira via fertirrigação e adubação convencional-atributos químicos do solo

A field experiment was carried out in Pindorama (Sao Paulo State, Brazil) in which it was evaluated the effects of N and K application through fertirrigation and conventional fertilization on soil chemical properties in a banana plantation, during two cycles of production. Nutrient (P, K, Ca and Mg) availability and movement in soil profile and some chemical properties (organic matter, pH and base saturation) were evaluated through samples carried out in the experiment implantation and at the end of the first and second production cycles. The most important treatment effects were on soil pH and on exchangeable K. Fertilizers, applied by fertirrigation or conventional fertilization, increased soil pH specially in soil layer depth of 0 to 20 cm. It was observed that the impact of pH soil fertilization via fertirrigation was proportional to fertilizer rate. The conventional fertilization also caused a pH decrease on soil, and it was more intense near the plants, reflecting the effect of fertilizer local application. The application of solid fertilizer on the soil surface determined a significant accumulation of exchangeable K on layers until the depth of 20 cm and in the region nearer the plant pseudo-stem . The effects of fertirrigation on soil chemical properties were more diffuse because fertilizers were spread in a larger area than the application of conventional fertilization.

Variabilidade espacial de atributos físicos de um argissolo vermelho-amarelo cultivado com leguminosas consorciada com a seringueira

O objetivo deste trabalho foi avaliar a distribuicao espacial de alguns atributos fisicos do solo e verificar suas alteracoes no desenvolvimento da seringueira consorciada com leguminosas. O experimento foi instalado em Argissolo Vermelho-Amarelo no Polo Regional de Desenvolvimento Tecnologico dos Agronegocios do Centro-Norte, localizado em Pindorama (SP). Foram avaliadas: infiltracao de agua a 0,10 e a 0,20 m de profundidade, macro e micro porosidade e densidade do solo nas camadas 0-0,10; 0,10-0,20; 0,20-0,40 e 0,40-0,60 m. O desenvolvimento das plantas de seringueira foi avaliado medindo-se o perimetro do caule e o aumento desta medida no periodo de quatro anos (1996-1999). Os dados foram submetidos a analise de estatistica descritiva para verificacao de parâmetros de tendencia central e dispersao. Foram utilizados metodos geoestatisticos incluindo semivariogramas, krigagem e mapas de isolinhas para a avaliacao da variabilidade espacial. Houve dependencia espacial de moderada a forte para todos os atributos do solo, com o valor do alcance variando entre 15 e 90 m. A dependencia espacial anotada para infiltracao de agua no solo nao teve relacao com as avaliacoes efetuadas nas plantas nem com os outros atributos avaliados. Os altos valores de densidade do solo e de microporosidade na camada de 0,20-0,40 m indicaram a ocorrencia de compactacao nesta camada. O perimetro do caule de seringueira aumentou linearmente com o tempo, porem a taxa de crescimento do perimetro do caule decresceu ao longo dos anos. A taxa media de crescimento do perimetro do caule variou em funcao do crescimento menor no inverno quando comparado com o do verao. Na distribuicao espacial do espessamento do caule das arvores de seringueira ao longo do tempo houve alta continuidade, avaliada pelos baixos valores do efeito pepita dos semivariogramas e estreita correlacao com densidade do solo, onde locais menos densos tiveram os maiores valores para o perimetro do caule da seringueira.

Seca-da-mangueira XXII: sobrevivência de variedades poliembriônicas

A doenca seca-da-mangueira e causada pelo fungo Ceratocystis spp., que provoca a morte de mangueiras em diversos estados brasileiros. O objetivo do trabalho foi avaliar a sobrevivencia de variedades de mangueira, utilizadas como porta-enxertos, em condicoes de campo e casa de vegetacao. Variedades poliembrionicas de mangueira foram testadas para resistencia a Ceratocystis spp.pelo metodo de inoculacao do fungo via solo, em casa de vegetacao. As plantas sobreviventes foram plantadas como pe-franco na Estacao Experimental de Pindorama (IAC), e as consideradas promissoras foram multiplicadas por enxertia em diversos porta-enxertos. Apos 17 anos do plantio, avaliou-se o numero de plantas mortas e verificou-se que, para o porta-enxerto Manila , considerado resistente, todas as plantas estavam vivas, enquanto Coquinho, considerado suscetivel, apresentou 58,3% de plantas mortas. Dois isolados de C. mangicola M. van Wyk and M.J. Wingf. foram utilizados para avaliar a resistencia das variedades de mangueira, em casa de vegetacao. O patogeno foi cultivado em meio de cultura BDA e transferido para o meio liquido BD. Foram realizadas oito inoculacoes sucessivas, com intervalo minimo de 30 dias. As avaliacoes foram realizadas pelas porcentagens de plantas mortas. O delineamento experimental utilizado foi blocos ao acaso, com 15 variedades e quatro repeticoes. O metodo de inoculacao via rega de solo, com 5 mL de inoculo a concentracao de 106 esporos . mL-1 foi eficiente para selecionar porta-enxertos de mangueira resistentes a C. mangicola. As variedades Vitoria, IAC 112, Dura e Bocado mostraram ser resistentes ao isolado de C. mangicola neste experimento. A variedade Juliana apresentou o mesmo nivel de suscetibilidade da variedade Coquinho. Recomenda-se evitar essas duas variedades para uso como porta-enxertos em areas onde ocorre a doenca.