Antonio Williams Moita

Reaction of coffee genotypes to different populations of Meloidogyne spp.: detection of a naturally virulent M. exigua population

The reaction of seven genotypes of Coffea arabica to 10 Meloidogyne spp. populations collected mainly from coffee plantations in Brazil and Costa Rica was evaluated under greenhouse conditions. The inoculum consisted of 10,000 eggs per plant. Evaluations were done 8 months after inoculations considering the root fresh weight, gall and egg mass indices, number of eggs per gram of root and reproduction factor (RF). The cultivars Obata IAC 1669-20, Sarchimor IAC 4361 and Tupi Amarelo IAC 5111 exhibited susceptibility to the four Brazilian M. exigua populations tested. However, cv. Tupi Vermelho IAC 1669-33 revealed resistance (RF value of 0.7) to the M. exigua population from Lavras, Minas Gerais State, Brazil. A population of M. exigua from Bom Jesus de Itabapoana, Rio de Janeiro State, Brazil, was highly virulent on cv. IAPAR 59 (RF= 165.7), bearing resistance gene Mex-1, and was also virulent on genotype Paraiso (H 419-5-4-5-2) (RF=396.2). A Meloidogyne sp. population on coffee from Garca, Sao Paulo State, Brazil, reproduced at low rates (RF ranging from 0.1 to 3.9) on all genotypes. All tested cultivars were susceptible to M. incognita and M. paranaensis. M. mayaguensis of guava from Parana State, Brazil, reproduced at low rates in all coffee genotypes; however, another population of coffee, from Costa Rica, was more aggressive and showed RF value that ranged from 0.8 to 12.4. Results of this study point for the first time to the ability of a naturally occurring M. exigua population to overcome the resistance conferred by the Mex-1 gene.

Host status of different crops for Meloidogyne ethiopica control

Two greenhouse experiments were carried out to characterize the resistance or susceptibility reactions of 52 species of plants to Meloidogyne ethiopica and their possible adverse effect on nematode population under greenhouse conditions. Tested plants with Reproduction Factor less than one (RF<1.0) were rated as non-hosts or resistant, including: peanut (Arachis hypogaea) ‘Cavalo Vermelho’, forage pigeon peas (Cajanus cajan) ‘IAPAR 43’and ‘PPI 832’, Crotalaria grantiana, C. apioclice, C. spectabilis, dwarf velvet bean (Mucuna deeringiana), castor bean (Ricinus communis) ‘IAC 80’, sorghum (Sorghum bicolor) ‘SARA’, cowpea (Vigna unguiculata) ‘Espace 10’ and ‘Australian’, black oat (Avena strigosa) ‘IAPAR’ 61’, ryegrass (Lolium multiflorum ) ‘Italian’, forage radish (Raphanus sativus var. oleiferus) IPR116’ and rye (Secale cereale) ‘IPR 69’. The first 11 are summer plants and the last four winter plants. The other 37 species/cultivars tested were good hosts or susceptible. Some crop succession systems alternating summer and winter non-host plants are suggested for field experiments to validate these greenhouse results.

Concentration of β-ecydisone (20E) in susceptible and resistant accessions of Pfaffia glomerata infected with Meloidogyne incognita and histological characterisation of resistance

Pfaffia glomerata is a medicinal plant widely distributed in Brazil, which is considered the worlds greatest supplier of P. glomerata roots. Among active ingredients contained in this plant, the steroid β -ecydisone (20E) is the most important compound extracted from roots. This steroid presents therapeutic properties for the treatment of diabetes and haemorrhoids, besides having bioenergy, tonic and aphrodisiac effects. The root-knot nematode Meloidogyne spp. is a major limiting factor in root production. Recent studies showed resistance of accessions of P. glomerata to Meloidogyne incognita . The aims of this work were: i ) to correlate the concentration of 20E with resistance and susceptibility of P. glomerata accessions to M. incognita in inoculated and non-inoculated plants; ii ) to study the effect of the parasitism of M. incognita on the concentration of the steroid 20E in the roots; and iii ) to clarify resistance mechanisms by comparing the response of a highly resistant UFV with a highly susceptible accession (Farm) to nematode infection. The concentration of 20E in the healthy susceptible Farm accession was significantly higher than in the healthy resistant UFV accession, showing that the resistance mechanism was not related to 20E concentrations. Plants of the Farm accession infected with M. incognita showed higher levels of 20E than the non-infected control. A positive and significant Pearson correlation coefficient was observed between 20E concentrations and gall indexes. Resistance of UFV to the root-knot nematode M. incognita was associated with unidentified factors that limited nematode penetration or emigration of second-stage juveniles and with post-penetration responses, including the hypersensitive response. Giant cells were sometimes found in the resistant cultivar, but displayed a highly vacuolated and degraded cytoplasm with thinner cell walls than those induced in the susceptible accession. Microscope observations under UV light showed a strong autofluorescence, suggesting that phenolic compounds may be involved in ginseng UFV resistance.

Identificação das causas de perdas pós-colheita de cenoura no varejo, Brasília-DF

Carrot post-harvest losses were evaluated for one year in four stores of a supermarket chain in Brasilia, Brazil. Sampling was performed at two stages: at reception in the store and after exclusion or removal from retail displays. The proportion of large, middle, small and broken roots was measured. Damaged roots were classified in one of the following categories and measured: splitting, forking, mishaped roots, pathological breakdown, pest damage, mechanical damage, and unidentified damage. About 86,88 + 0,66% of the roots were 12-22 cm long (middle size). Wastage presented a higher proportion of small and broken roots and a lower proportion of middle and large roots. The incidence of green top in waste decreased, when compared to the sample taken before marketing, from 23,74 + 1,11% to 13,29 + 1,37%. This is an indication that a substantial proportion of roots with green tops were sold and therefore this defect do not seem to be a factor inducing loss. About 51% of the roots delivered at the supermarket were damaged and the most important defects were mishaped roots (31,0 + 1,16%), mechanical damage (9,46 + 0,4%), and wilting (4,66 + 0,99%). The main causes of waste were mechanical damage (37,4 + 2,47%), mishaped roots (32,0 + 2,58%) and wilting (7,6 + 1,59%).

Atributos de hortaliças sob a ótica de consumidores: estudo de caso do pimentão no Distrito Federal

Capsicum (chili and bell peppers) breeders at Embrapa Vegetables are focusing project activities to satisfy the demands of both growers and final consumers in order to increase the chances of success in, long-term development of new cultivars. So, a prospection study on consumer demands and perception on bell peppers was started in 2007 in order to identify the main attributes taken in consideration during the act of purchase. This work was divided in two parts: a pilot study with 444 consumers at one supermarket and a survey with 500 consumers of fresh bell pepper, carried out by interviews at five supermarkets in Brasilia, Brazil, which represent distinct income segments. Data were analyzed by categorical data analysis using SAS (Procedure CATMOD) to rank the attributes in order of importance; to contrast the attribute means; and to verify the psychosocial influence on ranking the attributes during the purchase act. In addition, correspondence analysis was used for graphical representation of the attributes separated by the level of importance. During purchase, consumers prioritize the attributes related to the visual aspect (appearance) and firmness of the fruits. Also, differences of perception by gender, age, educational level, marital status and supermarket location were detected. Based on the collected evidence, elderly people are more concerned about nutritional value. Plant breeding programs can be better focused utilizing inputs from similar studies.

Meloidogyne spp. populations from native Cerrado and soybean cultivated areas: genetic variability and aggressiveness

A significant portion of the Cerrado (Brazilian savanna) has been replaced by major crops such as soybean. This may reveal populations of nematodes with different genetic backgrounds compared to cultivated fields. The objectives of this study were to evaluate the genetic variability and aggressiveness of isolates of Meloidogyne spp., contrasting nematodes from preserved areas of the Cerrado with those originating from cultivated soybean fields. Cluster analysis separated isolates of Meloidogyne spp. and isolates from Cerrado and soybean but did not separate an aggressive Meloidogyne morocciensis isolate. The aggressiveness of six selected populations of Meloidogyne spp. from Cerrado and soybean against soybean cultivars was evaluated. Results showed that populations of M. javanica and M. incognita from Cerrado and soybean showed similar aggressiveness. However, for M. morocciensis , the population from soybean was much more aggressive than the one from Cerrado. Aggressiveness is a very intriguing subject that needs special attention for future research in nematology.

Short-Term Changes in Fertility Attributes and Soil Organic Matter Caused by the Addition of EM Bokashis in Two Tropical Soils

The present work aimed to evaluate the behavior of ten fertility attributes of soil organic matter physical fractions and total organic carbon upon addition of three EM Bokashis to a Rhodic Ferralsol (FRr) and a Dystric Cambisol (CMd). An experiment was carried out in greenhouse in which the soils were placed into plastic trays and cultivated with tomato. A completely randomized design was used with four repetitions and factorial scheme of 2 × 3

Reação de genótipos de Capsicum ao nematoide-das-galhas

Reaction of Capsicum genotypes to root-knot nematode The objective of this research was to evaluate the response of experimental hybrids of Capsicum annuum [‘Experimental Hybrid (EH)’ and its Reciprocal (EHR)] and Embrapa Hortalicas elite genotypes of C. chinense, C. frutescens and C. baccatum to Meloidogyne incognita race 1, M. javanica and M. enterolobii. The hybrid pepper ‘Magali R’ was used as susceptible control to M. incognita race 1 and resistant to M. javanica, and as resistant controls to M. incognita race 1 and M. javanica ‘Silver’ and ‘Snooker’ rootstocks were used. ‘Rutgers’ tomato was used to confirm the viability of the inoculum. Two experiments were carried out in a greenhouse in a completely randomized design with six replications. Thirty-day old seedlings were transplanted to 2.0 L pots containing a mixture of soil, sand, cattle manure and carbonized rice husk (1:1:1:1). Plants were inoculated after transplanting with deposition of 5.0 mL of suspension containing 5,000 eggs and J2 of each species alone. After seventy days, plants were assessed by measuring the index of egg mass and galls, the number of eggs per gram of roots and the reproduction factor. The C. annuum experimental rootstock hybrids were resistant to M. incognita and M. javanica and susceptible to M. enterolobii, similar to ‘Silver’ and ‘Snooker’. The hybrid ‘Magali R’ only showed resistance to M. javanica. Elite genotypes of C. chinense and C. baccatum were susceptible to all three species, while genotypes of C. frutescens were susceptible only to M. enterolobii. The experimental hybrids of Capsicum annuum and most genotypes of C. frutescens may be used in protected cultivation areas infested with M. incognita race 1 and M. javanica. However the search for resistant genotypes to M. enterolobii, as well as the development and adoption of control strategies is of crucial importance.

Produção comercializável e teores de Cu e Zn em cenoura em decorrência da ação residual de fósforo e composto de lixo em solo sob cerrado

A field experiment was conducted on a clayey Yellow Red Oxisol to evaluate the residual effect of the application of phosphorus and urban waste compost of the previous two years on the root production of carrot cv. Brasilia. The soil of the previous experiment design used a factorial consisting of three levels of phosphorus (0; 400 and 800 kg ha-1), applied as triple superphosphate combined with five levels of urban waste compost (0; 20; 40; 60 and 80 t.ha-1), was arranged in randomized complete blocks with three replicates. Carrot plants were harvested 90 days after planting. After the harvest, a linear and quadratic effect for phosphorus and urban waste compost (p<0,01) was observed. The linear interaction P x quadratic urban compost was highly significant (p<0,01). The maximum root total production was 26.5 t.ha-1 corresponding to 18.5 t ha-1 of marketable yield, estimated by the calculated doses of 762.5 kg ha-1 of P2O5 and 53.2 t ha-1 of urban waste compost according to the function: Y(PROD) = 4.541143 + 4.0088 x 10-2 P2O5 + 2.50486 x 10-1 CLx - 2.5619 x 10-5 (P2O5)2 - 1.9125 x 10-5 (CLx * P2O5) - 2.216 x 10-3 CLx2 (R2 = 0,96), where CLx = urban waste compost. Doses of urban waste compost applied to the soil, affected the values of pH, electric conductivity, and the available contents of Cu and Zn. Even under the highest levels of phosphorus and urban waste compost applied in the experiment, no phytotoxic effect on carrot plants was observed, and in the edible part, none of the elements reached the maximum tolerant limit for food, as established by the Brazilian legislation.

Genetic variability of Meloidogyne paranaensis populations and their aggressiveness to susceptible coffee genotypes.

Meloidogyne paranaensis is one of the most destructive root-knot nematode (RKN) species parasitizing coffee in Brazil and in the Americas generally. The objectives of this study were to assess the genetic variability, aggressiveness and virulence of seven different M. paranaensis populations on susceptible and resistant Coffea spp. All seven RKN populations were identified by biochemical and molecular methods. Coffee seedlings were inoculated in the greenhouse, and the nematode reproduction factor was used to infer their reproduction on coffee genotypes. Phylogenetic studies showed a low genetic variability in M. paranaensis populations, regardless of the existence of three esterase phenotypes (Est P1, P2 and P2a), except for the population Est P2a from Guatemala, which is genetically different from other M. paranaensis populations from Brazil. The Est P2a and Est P2 (Herculândia, SP, Brazil) populations were the most aggressive on two susceptible C. arabica cultivars under greenhouse conditions. None of the M. paranaensis populations was virulent on resistant coffee genotypes, confirming their resistance to the seven M. paranaensis populations tested. The resistant coffee cultivars, namely Clone 14 INCAPER, Catuai Vermelho x Amphillo MR2161 (E1 16-5 III), Apoata IAC 2258, Timor Hybrid UFV 408-01 (E1 6-6 II) and IPR 100, exhibited segregation for resistance in the ratio of 0%, 2.4%, 12%, 26% and 29%, respectively. These are promising results, because they validate resistance against several M. paranaensis populations in different Coffea spp. genetic resources, which can be used in breeding programs or as rootstocks, such as ‘Apoata IAC 2258’ and ‘Clone 14 INCAPER’. This article is protected by copyright. All rights reserved.