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Many consumers in the U.S. claim to prefer low fat foods, and this has encouraged the search for peanut (Arachis hypogaea L.) cultivars with low or reduced oil content. A collector's note on the low oil content of PI 576616, a Peruvian-type peanut (A. hypogaea subsp. hypogaea var. hirsuta Köhler) prompted screening of similar landraces from Mexico. PI 576633, PI 576634, PI 576635, PI 576636, PI 576637, and PI 576638 were collected in 1993 and imported to the U.S. for evaluation. In 1994, 120plants per landrace were planted in the field, using Peruvian hirsuta PI 501296 as a control. In 1995, 24 selections from each Mexican landrace, 10 selections from PI 501296, and North Carolina State Univ. (NCSU) breeding line N91026E were planted. Based on oil analysis of the lines tested in 1995, 23 low oil and eight high oil selections were planted with four NCSU virginia-type breeding lines (N91026E, N92038, N94006L, and N94014L) used as controls in 1993. Nuclear magnetic resonance (NMR) was used for oil content determination. From the 1994planting, selections from PI 576633 and PI 576638 had the lowest oil content. Five selections from PI 576634 and PI 576635 with low oil content also were identified. Earlier screening of 580 entries in the NCSU germplasm collection identified only three lines with similar oil contents. In 1995, significant (P ≤ 0.01) oil content differences were found between landraces collected from the states of Puebla and Guanajuato (482 vs. 504 g kg−1). Significant variation was found among Puebla landraces, but no differences were found among Guanajuato landraces. In 1996, significant year-to-year variation was found for some of the 31 selections. Low oil lines have been identified with the potential to be used as parents in breeding for reduced oil content.

Low molecular weight organic acids (LOAs) and fatty acids in root exudates of two lupin cultivars, Lupinus albus cv. Multolupa and L. luteus cv. Tremosilla, were determined at flowering and fruiting stages. LOAs were analysed by capillary electrophoresis. Acetic and citric acids were the most abundant, especially the latter in L. luteus at the flowering stage (5922.79 µg/g dry root). The significant decrease in acid content of both cultivars from flowering to fruiting stages was also striking. The highest levels of acetic acid were detected in L. luteus at fruiting stage (1542.03 µg/g dry root). The significant citrate production in L. luteus could be related to the low phosphorus concentration in the studied soils but not to proteoid roots, which were detected only in L. albus. The source of the LOAs detected in these exudates is also discussed, since they may be produced either by the plant or by the associated rhizobacteria. The profile of phospholipid fatty acids was determined by high-resolution GC. A high level of 18:2ω6 (a fatty acid specific to fungi) was found in exudates of L. luteus (a mycorrhizal plant) in contrast to L. albus (a non-mycorrhizal plant). Copyright © 2001 John Wiley & Sons, Ltd.

A study of the rhizobacteria communities of Vicia villosa was carried out during the phenological cycle. The main genera were Bacillus and Pseudomonas. The genetic divergence between Bacillus strains was studied by RAPDs-PCR and difertenciated 15 Bacillus strains groups with a genetic divergence under 10%. One strain of each of the 15 groups was randomly chosen and all were tested on 20 days old Vicia villosa plants grown in vermiculite, in order to know the effect on nitrogen fixation. The nitrogen fixation was estimated by the total nitrogen per plant.

For the past 10-15 years Brazil has undergone wide-ranging outbreaks of locusts and grasshoppers. Rhammatocerus schistocercoides (in the State of Mato Grosso/western central region, 1984-88/1991-92), Schistocerca pallens and Stiphra robusta (in Pernambuco, Paraiba, Piaui, and Rio Grande do Norte/northeastern region, 1984-86/1991-92); Rhammatocerus conspersus, R. pictus, and Staurorhectus longicornis (in Rio Grande do Sul/southern region, 1989-1992) are some of the species that have become major pests. At present there are locust/grasshopper outbreaks in at least five Brazilian States, including Mato Grosso, Paraiba, Rio Grande do Norte, and Pernambuco. Although climatic conditions play an important role in locust outbreaks, the major factors that have originated this problem in Brazil are related to changes in land management, deforestation, introduction of new crops, and to some extent the lack of monitoring and vigilance once the outbreaks are suppressed. As a result of the implementation of locust/grasshopper control campaigns in Mato Grosso (1984-1988) and Rio Grande do Sul (1991-92), it has become evident that the locust/grasshopper problem in Brazil needs a different approach. To deal properly with the situation the Government needs to establish an integrated locust/grasshopper control program, but little is known about alternative control methods, and in some cases even the ecology of the species is poorly understood. Preliminary studies on biological control and ecology of several species involved are being carried out at present in Brazil in order to undertake a long term project to establish an integrated locust/grasshopper control program. This paper outlines the present situation of the locust and grasshopper problem in Brazil. It provides up-to-date information on the most recent outbreaks and analyses those factors that may have caused an increase in locust/grasshopper populations in several states. The limitations and implications of current control campaigns are discussed, and the need to establish an integrated control program is stressed [

The three species of Mexican katydids Pterophylla beltrani (Bolivar and Bolivar 1942), Pterophylla robertsi (Hebard 1941) and Pterophylla baezi (Bolivar and Bolivar 1942) are morphologically very similar. P. beltrani and P. baezi exhibit "green" and "pink" morphs while P. robertsiwas only recorded in the green form. The shared colour forms plus the morphological similarity has caused taxonomic problems, particularly between P. beltrani and P. robertsi. Here we describe the acoustic signals of P. beltrani and P. robertsi and use these signals to clarify their taxonomy. Calling and courtship signals of both species consist of phrases made up of pulses. The highest degree of separation between the species (98%) was obtained in a discriminant analysis of the courtship signals. Phrase rate per minute, duration of pulse no. 1 and duration of pulse intervals were the most important discriminating variables. Factors causing variation in P. beltrani and P. robertsi acoustic signals are discussed and the role of acoustic signals as a Specific Mate Recognition System is stressed. Acoustic results are supported by morphometric studies which enabled a 100% separation between the species and provided diagnostic characters. Hybridization tests failed to produce any offspring. [

Pterophylla beltrani(Bolivar & Bolivar 1942) is an important forest pest in north-eastern Mexico. The species exhibits green and pink morphs. Allopatric populations differ greatly in size, wing venation and colour. To gain insight into the status of different populations, we studied variation in acoustic signals and morphometric characters within and between three allopatric populations of P. beltrani. Some divergence in acoustic signals has occurred but a discriminant analysis of the signals failed to separate the populations completely. Despite the divergence in acoustic signals males and females from all populations still recognize each other as mates and readily mate if brought together. Divergence in morphology has ocurred more rapidly than in acoustic signals as the populations can be completely separated by a morphometric analysis. Indications of genetic incompatibilities between the populations were revealed by lower numbers of eggs laid, reduced percentage of egg hatch and distorted sex ratios of interpopulation crosses. From these results we suggest that P. beltrani is one species consisting of several subspecies which are in the process of developing into separate species (