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Toll-like receptors (TLRs) constitute an essential family of pattern recognition molecules that, through the direct recognition of conserved microbial components, initiate inflammatory responses after infection. Phylogenetic evidence suggests that vertebrate TLRs are under strong purifying selection for the maintenance of function. Our lab is focused on a related group of vertebrate TLRs that comprise the TLR2 subfamily. The most closely related members, TLRs 1 and 6, appear to have arisen from a recent gene duplication event and have acquired differential microbial recognition specificity. We have characterized two single nucleotide polymorphisms (SNPs), P315L, and I602S, in human TLR1 that effect receptor function through different mechanisms. The 315L variant is associated with deficient recognition of microbial products whereas the 602S variant is associated with aberrant trafficking of the receptor to the cell surface. It is surprising to note that the 602S allele is associated with a decreased incidence of leprosy suggesting that Mycobacterium leprae subverts the TLR system as a mechanism of immune evasion. TLR1 I602S exhibits strikingly different allele frequencies among different races suggesting that if strong purifying selection took place, it was restricted by either additional genetic or environmental factors that were geographically constrained.High expression of transgenes is desired for molecular farming. However, transgenes are often subjected to gene silencing pathways in plant cells. Gene silencing may be triggered by the production of aberrant (hairpin) RNA molecule from a complex integration locus in plant genome or by the overexpression of transgene. Excessively transcribed RNA are subject to gene silencing even if they are produced from a single-copy locus. Therefore, we sought to determine how highly a transgene can be expressed before its transcript is subjected to gene silencing. In a previous study, we demonstrated that precise single-copy locus generated by Cre/lox-mediated site-specific integration (SSI) in rice is stably expressed at predictable levels through subsequent generations, and that its expression invariably doubled in homozygous progenies. To further explore the stability of the SSI locus and determine the expression-threshold of rice genomic sites, we generated transformation vectors containing 1–3 copies of 35S-GUS and 35S-GFP transgenes. These vectors were used to develop SSI locus containing 1–3 copies of each transgene in two different varieties of rice, Nipponbare and Taipei 309. SSI lines will be analyzed by PCR and Southern blotting to ascertain the presence of precise integration structures consisting of 1–3 copies of each trans-gene. The precise SSI lines will be subjected to quantitative GUS and GFP assay to determine if gene expression indeed increased with the increase in gene dosage. Molecular and expression data of SSI lines will be presented.Tobacco plants (Nicotiana tabacum L.) were transformed with a construct based on pCAMBIA 2301 containing a “hairpin” inverted repeat of 598 nucleotides derived from the Potato Virus Y (PVY) replicase (NIb gene) of the N strain (Robaglia et al., J. Gen. Virol. 70, 935, 1989). Such constructs confer virus resistance by a post translational gene silencing mechanism. Homozygous (T3) plants were challenged with a range of PVY strains and resistance was measured by symptom expression, ELISA titer, and back inoculation of controls with extracts from resistant plants. The nucleotide homology of PVY strains to the transgene was: WP (99.5%) PVY-NTN (96.3), PVY-H (95.6%), PVY-O (88.9%), strain 52 (88.3%), and local field isolates from tomato (86.8%), and pepper (86.3%). A transgenic tobacco line was immune to the five PVY strains with which the transgene had the greatest homology (WP, NTN, H, O, 52). Infection with the PVY isolates from tomato and pepper, which had the lowest degree of homology with the transgene, caused delayed symptom appearan

Soil acidity and aluminum (Al) toxicity are major problems limiting performance of alfalfa (Medicago sativa L.) in many parts of the world, but neither an effective screening procedure nor a tolerant cultivar is available. The objective of this study was to evaluate different screening methods for selection of acid soil tolerant alfalfa germplasms in the greenhouse during 1991-1994. The general screening methods included selection in unlimed soil, selection in unlimed soil containing a limed germination layer, selection for either tolerance or sensitivity to acid soil stress with Al toxicity in tissue culture, selection in unlimed soil with tandem selection for Al tolerance in tissue culture, and selection in unlimed soil containing a limed, fertilized germination layer with tandem selection for Al tolerance in tissue culture. All selected populations and checks were evaluated during 1994 in greenhouse cups containing the following soil treatments : (i) cups filled with unlimed soil, (ii) cups filled with limed soil, and (iii) cups filled with unlimed soil containing a germimation layer of limed soil. Most of the selected populations possessed better root and shoot growth than the original base population (GA-TE) in unlimed soil, but only the population selected in unlimed soil showed better root and shoot growth in unlimed soil with a limed germination layer. No population had poorer performance than GA-TE in limed soil. Selection ih cell culture for Al toxicity tolerance did not improve tolerance per se, but selection for Al sensitivity enhanced sensitivity. In terms of success, resources, and time, screening in unlimed soil was the most effective method to improve acid soil stress tolerance.

Lines of transgenic cotton, Gossypium hirsutum L., that contain a truncated version of the delta endotoxin gene from the bacterium Bacillus thuringiensis var. kurstaki were tested in the laboratory for effects on growth and survival of tobacco budworm, Heliothis virescens (F.). Five transgenic lines contained the cryIA (b) gene from bacterial strain HD-l and one cotton line (MON-249) had the cryIA (c) gene from the strain HD-73. Neonate larvae of tobacco budworm were grown for 6 d on 10 different kinds of plant structures of the six transgenic, field-grown cotton lines and the nontransgenic, parental ‘Coker 312’. Mean growth and survival of neonate larvae to 6 d for the transgenic lines as a group were significantly less than ‘Coker 312’ for every plant structure. Among the six transgenic lines, significant variation in survival of neonate larvae to 6 d on terminal leaves, small squares, and on bracts were observed; however, insect weights were very low and not different among transgenic lines. When larvae were fed on artificial diet before they were placed on mature leaves they tended to have higher survival on one transgenic line (MON-62) than on the others. No larvae pupated on transgenic lines. These laboratory assays using field-grown plant struchues indicate that cotton transgenic for delta endotoxin has great potential in controlling tobacco budwonll larvae under field conditions.

An improved Heliothis virescens F. egg harvester was designed, constructed, and evaluated. The machine automatically removes eggs oviposited on screens, recycles the wash solution (sodium hypochlorite) for reuse, and rinses the eggs with tap water. Results showed that H. virescens eggs removed mechanically with the egg harvester hatched as well as eggs removed manually. Daily collection rates over a 60-d test period averaged 360,000 eggs. On peak day of egg collection, ≈700,000 eggs were collected in ≈20 min. The improved machine has built-in features for limiting the time eggs are exposed to the sodium hypochlorite solution, immediately rinsing the eggs with tap water, and a feature to prevent harvest of eggs if the collection screen is not properly in place.

In 1987 and 1989, cotton, Gossypium hirsutum L., plants at different developmental stages were artificially infested with five neonate tobacco budworm, Heliothis virescens (F.), larvae per plant. The position of each open boll on the plant was recorded at harvest. Infestations, regardless of the developmental stage of the plant, reduced boll numbers at the first fruiting position on the branch. Boll distributions at position 1 on plants infested at the 5th-node stage of growth were similar to plants infested at the 15th-node stage. However, plants infested at the 15th-node stage set a greater number of bolls at position 2 than plants infested at the 5th-node stage. Only plants infested at the 5th-node stage had fewer total bolls than the control. DES-119, an earlymaturing cotton, produced more bolls at positions 1 and 2 on the lower nodes than ST-825 when plants were infested at the 7th-node stage of growth. When plants were infested at the 12th-node stage, DES-119 produced more bolls at position 1 on the lower nodes, whereas ST-825 produced more on the upper nodes. There was no varietal difference in boll production at position 2 of plants infested at the 12th-node stage.

Female moths of the tobacco budworm, Heliothis virescens (F.), oviposit in terminals of the cotton plant, Gossypium hirsutum (L.). The hatched larvae feed in the terminal area, then migrate to small squares (buds) where they feed and finally burrow into and feed on the anthers, where they grow rapidly. They attempt to avoid feeding on gossypol glands during the first 48 h after hatching. When tobacco bud worm neonate larvae were fed squares of highly glanded lines, growth was decreased by 25–75%. The number of glands in calyx and bract tissues of squares of resistant lines was significantly higher than in susceptible lines. The difference was greatest in the calyx crown where the ratio in resistant to susceptible lines was 10–20 fold. The calyx crown of highly glanded resistant lines also was high in terpenoid aldehydes. High pressure liquid chromatography data showed that the gossypol content of susceptible and resistant glanded lines is equal, whereas three other terpenoid aldehydes, hemigossypolone and heliocides H1 and H2, are greatly increased in resistant lines, and they are presumably more closely associated with resistance.

Asiatic cottons [Gossypium arboreum (L.)] have been investigated as a source of resistance to the tobacco budworm [Heliothis virescens (Fab.)] because their diversely colored petals have been presumed to contain various allelochemicals. However, we found that larvae fedG. arboreum squares (buds) grew about equally compared with those fed squares from commercialG. hirsutum lines. The best source of resistance was found in severalG. hirsutum double-haploid (DH) lines. In our investigation of allelochemicals, G.arboreum lines were found to contain much less gossypol in leaves, squares (buds), and petals thanG. hirsutum L. lines. Flavonoids were significantly higher inG. arboreum lines only in petals. Of 22G. arboreum lines from which squares were gathered and fed to tobacco budworm (TBW) larvae in the laboratory, larval growth was not significantly decreased on any, but larval survival was decreased on six. When the square flavonoids were isolated and incorporated in laboratory diets for the TBW, moderate toxicity was observed. However, the estimated toxicities were not greater than those of the same flavonoid isolates fromG. hirsutum lines. The most prevalent flavonoids, all previously found in G.arboreum plant tissues, were gossypetin 8-0-glucoside and gossypetin 8-0-rhamnoside, neither of which were present inG. hirsutum tissue. Quercetin 3-0-glucoside, quercetin-3'-0-glucoside, and quercetin 7-0-glucoside were also present in significant amounts in both species. Gossypetin 8-0-rhamnoside and gossypetin 8-0-glucoside were the most toxic flavonoids tested (the ED50% was estimated to be 0.007 and 0.024) and therefore may prove to be contributing factors of resistance to TBW feeding.

The aviability of a tall fescue (Festuca arundinacea Schreb.) clone whose members are infected with different strains of its endophytic fungus, Acremonium coenophialum Morgan-Jones & Gams, would help identify the individual contributions of the endophyte and tall fescue toward traits normally associated with endophyte-infected tall fescue plants

There is a paucity of information on the relationships between modern (i.e., released in or after 1978) and historically obsolete cotton (Gossypium hirsutum L.) cultivars with respect to their ability to yield when grown in the presence of high levels of tobacco budworm (TBW), Heliothis virescens F. The objective of this study was to compare 18 cultivars of cotton developed between 1890 and 1986 for ability to yield when grown with and without TBW infestations. This comparison was accomplished by growing cultivars for 2 yr under two regimes: (i) artificial infestation with TBW (w/TBW) and (ii) complete control of all insect pest (w/o TBW)

Cotton plants, Gossypium hirsutum L., initiate more fruiting buds than are matured. This research quantified the boll set percentage and boll size by fruiting site in a population of cotton plants. The fruiting sites of harvestable bolls were recorded for 2 yr in eight cultivars : Stoneville 213 (ST 213), Stoneville 506 (ST506), Stoneville 825 (ST 825), Tamcot CAMD-E (CAMD-E), Deltapine 50 (DPL 50), McNair 235 (MC 235), DES 119, and Deltapine 20 (DPL 20) (...)

Female moths of the tobacco budworm,Heliothis virescens (F.), oviposit in the terminals of the cotton plant,Gossypium hirsutum (L.). The hatched larvae migrate to the terminal area and then to small squares (buds), on which they feed, finally burrowing into the anthers where they grow and develop. They attempt to avoid gossypol glands as they feed. Chemically related evidence explains, in part, these observations. The calyx crown of resistant lines (which is avoided) is high in the terpenoid aldehydes (TAs) including gossypol. HPLC data showed that the gossypol content of both susceptible and resistant glanded lines is equal, while the hemigossypolone and heliocides H1 and H2 are greatly increased in resistant lines and presumably are more closely associated with resistance. Analysis for total amino acids in cotton square tissues showed that there was a gradation from the calyx and calyx crown, which were lowest, to the anthers, the site of final insect development, which were highest. Synthetic diets mimicking amino acid distribution in anthers were found to be successful for larval growth and development.

Diapausing tobacco budworm, Heltothis virescens F., pupae were stored underground in one of three different containers: 30-ml plastic cups (housed in 10.0-liter carboy) containing either sand, corncob grit, or 2% agar; 1.0-liter plastic containers containing sand; or 10.0-liter carboys containing 2% agar and corncob grit. Control pupae were stored in plastic Petri dishes in an environmental chamber at 1°C. Pupae were exhumed after 110 d. Samples from each treatment were placed in a diapause termination environment (27°C and constant light). Ninety percent of the control pupae emerged as adults. Of the pupae stored underground, those stored in 30-ml plastic cups containing either sand or agar had the highest percent emergence (68%).

The success of tetraploid red clover (Trifolium pratense L.) in Europe has stimulated interest in developing tetraploid red clover adapted to the United States. The use of 2n gametes to produce tetraploid alfalfa (Medicago sativa L.) and potato (Solanum tuberosum L.) from diploid germplasm suggests that 2n gametes may be an alternative to chemical treatment. Diploid plants that produce 2n eggs are known to occur in red clover, and plants that produce 2n pollen have been reported. The objectives of this study were to search for red clover plants producing 2n pollen, and to determine the cytological origin of such pollen. Six hundred plants, belonging to six different diploid (2n = 2x = 14) cultivars, were screened for 2n pollen production by examining dry pollen samples with the aid of a microscope. Eighteen plants (3%) produced at least 1% 2n pollen and were classifted as 2n pollen producers. Individual plants ranged from 1 to 84% in frequency of 2n pollen production. Pollen mother cell analyses revealed that 2n pollen resulted from parallel or tripolar spindles during anaphase II of microsporogenesis. This mechanism is genetically equivalent to a first division restitution (FDR) mode of gamete formation. One 2n pollen producer proved to be a synaptic mutant. Normally, synaptic mutants are male sterile, but fertility is restored by parallel spindles in this plant. Because the lack of homologous pairing limits genetic recombination, this plant can produce gametes with the same genetic constitution as the sporophyte. It is apparent from the results that 2n gametes may be useful in red clover polyploidization programs. Additional index words: Parallel spindles, Trifolium pratense L., Synaptic mutant, Tetraploid red clover, 2n gametes. R clover (Trifolium pratense L.) is a diploid (2n = 2x -14) species used as a forage crop .throughout the temperate regions of the world. There Is no evidence to date of naturally occurring tetraploid forms of the species; however, chemically induced tetraploids (2n = 4x = 28) have been produced. In certain parts of Europe, tetraploid forms are sometimes agronomicall~, superior to the diploid forms in yield, disease resistance, and persistence (Taylor and Smith, 1979). Considering the success tetraploids in Europe, it may be desireable to develop .tetraploid germplasm adapted to United States growlng conditions. The conventional method for obtaining red clover tetraploids has been through the use of colchicine or nitrous oxide. Recent research with 2n gametes in other species suggests that these gametes can be used as an alternative to chemical treatments in a breeding program. Production of 2n pollen has been extensively studied in potato, Solanum tuberosum L., (Mok and Peloquin, 1975), alfalfa, Medicago sativa L., (Vorsa and Bingham, 1979), and peas, Pisum sativum L., (Myers, 1981). First division restitution (FDR) 2n len has facilitated the transfer of germplasm from the diploid level to the tetraploid level in both potato 1 Cooperative investigation of USDA-ARS and the Wisconsin Agric. Exp. Stn., Madison, Wis. This research supported in part by U.S. Competitive Grant no. 8100349. Received 11 |uly 1983. ~ Research assistant, Dep. of Agronomy, Univ. of ~Visconsin, Madison, and supervisory research geneticist, USDA-ARS and professor of agronomy, Univ. of Wisconsin, Madison, WI 53706. (Peloquin, 1982) and alfalfa (Bingham, 1968). In these species, 2n pollen can be produced by disorientation of the meiotic spindles during anaphase II. The spindles may lie in one plane instead of two, in which case they are either parallel or tripolar. Parallel s.pindies lead to the formation of two restitution microspores, while tripolar spindles form one restitution microspore and two normally .reduced microspores. The]~roduction of 2n pollen via parallel or t~:~polar spindles is genetically, equivalent to the FDR mechanism of 2n gamete tormation. All the heterozygous loci from the centromere to the first crossover are preserved in each chromosome arm, 50% from the first crossover to the second, and 75% in each successive crossover. Thus, most of the heterozygosity present in the sporophyte is retained in the gametophyte and subsequently transmitted to the progeny (Mendiburu and Peloquin, 1977). A synaptic mutant, occurring together with parallel spindles during anaphase II, has been described in potato. The combination of these two mutants leads to the formation of pollen with exactly the same genetic constitution and heterozygosity as the sporophyte. This occurs as the lack of normal pairing significantly reduces crossing over, resulting in a corresponding increase in the amount of heterozygosity transmitted by a restitution gamete. When the lack of pairing is complete the genome of the gametophyte is identical to that of the sporophyte (Peloquin, 1983). Maximizing the heterozygosity in autopolyploids is important (Dunbier and Bingham, 1975), and FDR 2n gametes can be an effective breeding tool for autopolyploid crops (Mendiburu et al., 1974; Bingham, 1979). Red clover plants that produce 2n eggs have been identified (Broda and Smith, 1980; Taylor and Giri, 1982), suggesting that 2n gametes can be used to produce tetraploid red clover germplasm. The only report of functional 2n pollen within the true clovers (Trifolium spp.) has been in T. alpestre L. (Maizonnier, 1972). Strzyzewska (1974, 1976) reported the formation of 2n pollen by post meiotic fusion in diploid red clover, but pollen function was not tested in 4x2x crosses. Kazimierski and Kazimierska (1970) reported that a hybrid of T. repens L. X T. nigrescens Viv. produced dyads and triads. The authors also included a microphotograph of tripolar spindles. The objectives of this investigation were to search for plants which produced 2n pollen in diploid red clover and to determine cytologically the origin of the 2n pollen. MATERIALS AND METHODS In red clover, x and 2x pollen can be easily distinguished by their distinct morphology when dry. Haploid pollen is oblong and regular in shape, while diploid pollen is triangular, square, or irregular in shape (Taylor et al., 1976). Red clover flowers were tripped on a slide, and the pollen was then examined under low magnification. One thousand grains from each plant were scored for ploidy level. In all, 600 plants, 100 each from six diploid red clover cultivars

Young tobacco budworm, Heliothis virescens (F.), larvae prefer to feed along the margin area of the calyx crown of cotton ( Gossypium hirsute L.) squares. This area is devoid of gossypol glands. On resistant cotton lines, which contain glands in the calyx crown, the larvae feed sporadically on the tissue and avoid the gossypol glands. The numbers of gossypol glands on bracts of small squares, calyx crown, bract mid-rib, and the entire calyx differed significantly between a susceptible and three resistant cotton lines. When young larvae were placed on squares for 12 d, the lines with >80 glands per small square bract or 30 glands per calyx crown produced larvae significantly smaller than did lines with fewer glands.

Feeding behavior and histological-histochemical studies of newly hatched tobacco budworm, Heliothis virescens (F.), larvae feeding on cotton Gossypium hirsutum L. revealed that first-stage larvae avoided consuming glands which contains gossypol, a dimeric sesquiterpenoid aldehyde. Between 48 and 72 h of age, larvae molt and then nonselectively consume the glands. Histological studies show that gossypol glands are surrounded by an envelope; histochemical procedures indicate that the envelope contains anthocyanins which differ from gossypol. We suggest that the allelochemics present in these glands act as feeding deterrents or as antifeedant compounds to first-stage larvae.

The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), reduces yield and delays maturity in cotton, Gossypium hirsutum L., in many parts of the southeastern cotton belt. The objectives of this study were: a) to determine the response of six cotton strains to this pest; b) to obtain information on gene action conditioning this response to tarnished plant bugs; and c) to select progeny in the presence of tarnished plant bugs for early-season yielding ability. The six strains evaluated were: Bulgarian 3279, Deltapine 7146N, DES-06, ORH 78-75, Stoneville 213 frego, and Coker 420 smooth nectariless. The four crosses utilized were: Deltapine 7146N X Bulgarian 3279 (cross 1), Stoneville 213 frego X Bulgarian 3279 (cross 2), Coker 420 smooth nectariless X ORH 78-75 (cross 3), and DES-06 X ORH 78-75 (cross 4). Resistance is based on the relative seedcotton yield and yield loss at first harvest in unsprayed plots as compared to insecticide-treated plots. Generation-mean analyses indicate that crosses 1,2, and 4 appear to have genes segregating for resistance to the tarnished plant bug. Dominant gene action was primarily responsible for seed-cotton yield and percentage of total seedcotton at first harvest (earliness), and boll weight. Inheritance of lint percentage was primarily additive. Several selected progeny tested under plant-bug infestations produced higher seedcotton yields at first harvest than their higher-yielding parent or control cultivar. Early maturity (higher percent of total seedcotton at first harvest) was maintained in most selections when plant bugs were present. Growing progeny under high levels of plant bugs allows both the elimination of the most susceptible lines and the identification of lines with resistance to the tarnished plant bug.

The endosperm balance number (EBN) hypothesis was first advanced to explain results from interspecific crosses in Solanum and later in Impatiens. According to the EBN hypothesis, normal endosperm development following intra- or inter-specific crosses depends on having a ratio of two EBNs from the female to one EBN from the male in the endosperm tissue. EBNs may differ among related species. Successful hybrids can be obtained between species with the same EBN. The ploidy level of an individual species can be varied to modify its EBN, making it cross compatible with a species sharing its modified EBN. Interspecific crosses within Trifolium have been limited and difficult. Crosses reported in the literature, including evidence from our own study, suggest that EBN is operating in Trifolium and have been used to assign EBN numbers to some clover species. The use of 2n eggs enabled two species, differing in EBN, to be crossed. An understanding of the EBN mechanism that operates in Trifolium should make successful interspecific hybrids easier to obtain in the future.Key words: endosperm balance number, hybrids (interspecific), 2n gametes, Trifolium.

Identification des effets de 8 produits chimiques isoles de plants de coton, sur la croissance des larves de Heliothis virescens, lorsqu'ils sont ajoutes a l'alimentation artificielle

Twenty-four diploid red clover (Trifolium pratense L.) plants, from the cultivars 'Arlington', 'Florex', and 'Redman', and C760, a Wisconsin synthetic, were tested for 2n egg production by crossing them with tetraploid plants. Four plants were identified and selected as 2n egg producers. These plants were then crossed with a known producer of 2n pollen in an attempt to obtain tetraploid plants through bilateral sexual polyploidization. Thirteen percent of the seed obtained in one of the 2x–2x crosses were tetraploid. The female plant produced an estimated 0.14 2n eggs per 1000 flowers in the cross. In a second experiment, bilateral sexual polyploidization was attempted, using 14 plants which had not been previously tested for 2n egg production. Two of these plants produced one and two tetraploids each, representing 2n egg frequencies of 3.33 and 5.00 2n eggs per 1000 flowers, respectively. It seems likely that it will be possible to use bilateral sexual polyploidization to tetraploidize red clover germplasm in the future.Key words: tetraploid red clover, Trifolium pratense. 2n gametes.

We hypothesized that the ♀ boll weevil, Anthonomus grandis Boheman, does not discriminate against squares in which an egg has previously been oviposited. We call this the non-discrimination hypothesis. The objective of this study was to compare the observed distribution of single and multiple eggs/square over a range of infestation levels (0–100%) with theoretical values based on our hypothesis. We observed 28,750 squares and classified 22,526 oviposition punctures in yr 1 and 6500 squares and 3549 oviposition punctures in yr 2. Our data support the non-discrimination hypothesis—the ♀ boll weevil did not detect squares containing an egg and did not discriminate against squares containing an egg. Large samples such as these allow a statistical approach to an understanding of some aspects of insect behavior that can not be obtained from observations of a small sample or of a small number of samples.

Column chromatography of the pentane extract of freeze-dried cotton buds or anthers yielded a wax-sterol ester fraction that exhibited potent feeding stimulant activity for the cotton boll weevil. The waxes of the wax-sterol ester mixture were responsible for the feeding activity. Saponification of the wax-sterol ester fraction yielded about 15% alcohols and 85% sterols. A C18∶1 alcohol, dihydrophytol, phytol, and geranylgeraniol constituted 15, 36, 26, and 23%, respectively, of the total alcohols, implicating certain of their long-chain esters as feeding stimulants. Several esters of dihydrophytol, phytol, and geranylgeraniol were identified among the waxes by GC-MS. Certain phytol, geranylgeraniol, and oleyl alcohol esters containing C12 to C26 acid moieties were synthesized and were found to induce high feeding stimulant activity in the cotton boll weevil.

Distribution of tobacco budworm, Heliothis virescens (F.) larvae within cotton, Gossypium hirsutum L., plants was studied from mid-June through August (weeks 8–18 of the growing season) in a natural population. Most 1st instars (75%) were observed on the upper third of the plant. Second instars were observed in the upper third of the plant except in weeks 14 to 18. Instars 3 to 6 moved throughout the plant. All larval stages were found in higher numbers on structures that arise from position 1 from the main stem. First instars were found on small squares, except in weeks 15 and 16, when more larvae were on small bolls than squares, and in weeks 8, 9, and 18 when they were on meristems or leaves. Second and 3rd instars fed on squares in early season and on bolls in late season. However, 2nd instars in weeks 8 and 9 were found on meristems or leaves. Most of the 4th, 5th, and 6th instars were found on small and medium bolls.

Nomarski differential interference contrast microscopy was used to study megasporogenesis in intact ovules of Solanum commersonii Dun., following staining with Mayer's hemalum and clearing with methyl salicylate or cedarwood oil. Previous studies in Solanum have observed the Polygonum type of megasporogenesis, in which a linear tetrad of megaspores is formed. The three micropylar megaspores then degenerate, leaving the chalazal megaspore to divide mitotically to form the egg sac. Contrary to expectation, only 30% of the observed sporads within the same ovary were tetrads. Triads, including some with one deteriorating cell at the micropylar end, were the predominant form. Many dyads, which are an intermediate stage in megasporogenesis, were found with one cell prematurely deteriorating. These observations can be explained if the micropylar daughter cell of the dyad stage, which formed after telophase I, began deteriorating before the second meiotic division, such that it never underwent the second division. The chalazal daughter cell would still undergo the second meiotic division, followed by death of the new micropylar megaspore.Key words: Solanum, potato, megasporogenesis, S. commersonii, ovule, clearing.

When quercetin, rutin, tannin, and gossypol were mixed in artificial adult and larval diets and fed to boll weevils, Anthonomus grandis Boheman, gossypol at 1.65 and 2.65% dry weight in the adult diet plugs caused a statistically significant increase in feeding, and levels of 1.15–2.15% significantly increased oviposition. Feeding was also increased at all other levels though not significantly beyond the base level of 0.15%. Gossypol, incorporated into larval diets in concentrations of 2.0–3.5%, significantly reduced the weight of emerging weevils, but 3.5% was required before the production of adults was significantly reduced. Quercetin did not significantly reduce feeding or oviposition. At levels of 0.1–0.6%, it increased the weight of emerging weevils, but at all other levels weight was not significantly affected. Tannin and rutin at levels of 0–1.0% did not significantly increase or decrease feeding. Tannin reduced weevil weight significantly at 0.2, 0.6, 0.8, and 1.0% levels; rutin at levels of 0.1–1.0% did not influence the weights of adult weevils at eclosion.

A large portion of the world's germ plasm of cotton has been screened at the USDA Boll Weevil Research Laboratory, State College, Mississippi during the period 1962–68 utilizing developed techniques. An oviposition suppression factor causing 25–40% reduction in number of eggs laid by the weevil has been found in Gossypium barbadense and successfully moved into upland cotton, G. hirsutum. Two years field data with frego cottons indicate that the frego character contributes a significant degree of non-preference for egg laying by the boll weevil under field conditions. The frego character is currently being combined with selected lines of G. hirsutum carrying the oviposition suppression factor. A seedling screening technique utilizing field cages and greenhouse sand flats has been shown to have significant value in screening for individual resistant plants within a commercial variety. A number of selections with 25% or more resistance to oviposition are under extensive investigation. A number of biologically active materials have been detected in the cotton plant and other hosts of the boll weevil which significantly influences feeding stimulation, feeding deterrency, repellency and attractancy of the weevil to its hosts. A highly active square abscission factor has been detected and extracted successfully from 2nd and 3rd instar larvae. The material injected into cotton squares causes 95% abscission of squares within 48–60 hours. ZUSAMMENFASSUNG RESISTENZ- UND ANFALLIGKEITSFAKTOREN DER BAUMWOLLE UND ANDERER WIRTSPFLANZEN GEGENUBER DEM BAUMWOLLKAPSELKAFER, ANTHONOMUS GRANDIS Ein groser Teil des Weltsortiments der Baumwolle wurde in den Jahren 1962–68 im USA-Baumwollkafer-Institut der Staatshochschule von Mississippi mit modernen Methoden getestet. Ein die Eiablage unterdruckender Faktor, der die Anzahl der abgelegten Eier um 25–40% herabsetzt, wurde bei Gossypium barbadense gefunden und erfolgreich in Hochland-Baumwolle, G. hirsutum, eingekreuzt. Zweijahrige Erfahrungen mit “frego”-Baumwolle weisen darauf hin, das das “frego”-Merkmal unter Feldbedingungen in einem signifikanten Ausmase zur Nonpraferenz fur die eierablegenden Kafer beitragt. Das “frego”-Merkmal wird laufend mit selektierten Linien von G. hirsutum kombiniert, die den Faktor fur Eiablage-Unterdruckung tragen. Eine Samlings-Prufungstechnik, die Feldkafige und Gewachshaus-Sandbeete benutzt, hatte nachweislich signifikanten Wert fur die Auslese resistenter Einzelpflanzen innerhalb einer Handelssorte. Eine Anzahl Selektionslinien mit 25 oder mehr Prozent Eiablage-Resistenz wird intensiv gepruft. Eine Anzahl biologisch aktiven Materials wurde bei Baumwolle und anderen Wirtspflanzen entdeckt, das Frasstimulation, Frasabschreckung, Repellenz und Attraktanz der Kafer in bezug auf ihre Wirte signifikant beeinflust. Ein hochaktiver Kapsel-Abwurf-Faktor wurde entdeckt und erfolgreich aus Larven des 2. und 3. Stadiums extrahiert. In Baumwollkapseln injiziert, verursachte dieses Material innerhalb 48–60 Stunden Abwurf von 95% der Kapseln.

Azinphosmethyl and methyl parathion applied at 0.125 pound per acre left greater deposits and caused higher mortality of Anthonomus grandis Boheman on frego than on normal bract cotton squares when: (1) weevils were caged in the field on the 2 types of cotton, (2) weevils were placed in 1-pint cartons with squares removed from the plant after spraying, and (3) when weevils were placed in cartons with squares sprayed after being picked from the plant. These results were confirmed by recovery of approximately 7 times the amount of residue from frego than from normal bract buds sprayed with methyl parathion.

A greenhouse seedling-selection technique was developed for mass screening seedling cotton, Gossypium sp., for resistance to Tetranychus urticae Koch. The salient procedures were mass rearing the two spotted spider mite on bean cotyledons for a constant source of mites, standardized greenhouse manipulation of plants, a plant-damage index for rating mite injury, and use of a standard variety for comparison of varietal resistance. The greenhouse seedling rating agreed with field rating and required Jess time (30 vs. 60 days). Fecundity was not a reliable indicator of resistance.

Thirteen germplasm lines of cotton, Gossypiumh irsutum L., including seven cultivars were grown for 3 years with and without tobacco budworm, Heliothis virescens F. There is a paucity of information available on the performance of cotton germplasm when grown under tobacco budworm infestation. Development of insecticide resistance in this insect or a loss of effective insecticides from the market would pose substantial problems for the cotton industry. Objectives of this study were i) to determine the performance of 13 diverse germplasm lines when grown under controlled, uniform levels of tobacco budworm infestation, ii) to identify germplasm useful to breedersf or use in developing cultivars resistant to tobacco budworm, iii) to identify germplasm lines with different levels of resistance useful for studies on how or why cotton germplasm resist tobacco budworm and iv) to develop information useful for improving breeding practices in cotton. Plots were grown on a Leeper silty clay loam, fine montmorilloritic, non-acid, thermic, chromondertic, Haplaquept, 0 to 2%s lope. Infested plots were inoculated with first instar tobacco budwormla rvae five to six times at weekly intervals beginning about the second week of squaring as determinedi n ‘Stoneville 213’. Worm-free plots were sprayed weekly with fenvalerate [cyano(3-phenoxyphenyl)methy4-chloroalpha-(l-methylethyl)benzeneacetate]. Resistance was measured as the ability to resist yield loss when continually infested with tobacco budworm larvae for 5 to 6 weeks. Resistance was identified in ‘Stoneville 506’ and confirmed in PEE DEE 875, PEE DEE 8619 and ‘Tamcot CAMD-E’. Because two are cultivars and are presently being grown, information on them can immediately be put to use. Each of the four germplasms should be useful to breeders as parental lines to increase resistance to tobacco budworm. Regression analyses on one year's data suggest that about 65% of the resistance is associated with early, rapid fruiting. However, additional unidentified factors are also involved.

A 3-year study involving a total of 15 environments was conducted to evaluate the effect of aldicarb on early-season control of tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois), and determine what impact this control would have on cotton, Gassypium hirsutum L., yield. Ten of the 15 environments had tarnished plant bug populations sufficient to affect yield. Results from this study show that aldicarb used at 2.24 kg (AI)/ha reduced tarnished plant bugs and increased yield, and aldicarb occasionally increased yield through some unknown mechanism which cannot be explained by reduced numbers of tarnished plant bugs.

A greenhouse procedure was developed for maintaining a culture of Trialeurodes abutilonea (Haldeman) on cotton, Gossypium hirsutum L. One U.S. and 35 foreign cotton cultivars were evaluated for relative levels of resistance or susceptibility to bandedwinged whitefly colonization and emergence of adults. When compared with the commercial cultivar ‘Deltapine 16’ (DPL-16), one foreign cotton, ‘C-1211,’ had significantly ( P = 0.05) lower levels of whitefly colonization. Six foreign cultivars, ‘Lasani 11,’ ‘M4 (N.T. Sind),’ ‘4S 180,’ ‘CX 349,’ ‘138-F,’ and ‘108-F,’ had levels of colonization that were not significantly different from DPL-16. None of the cultivars had significantly less adult emergence than DPL-16, and 17 had adult emergence levels that were not significantly different.