Evaluating the effects of crop successions in no-tillage system (NTS) is essential for the correct recommendation of agronomic practices, such as top-dressing nitrogen fertilization. The aim was to evaluate the effect of the crop succession and the splitting of top-dressing N fertilization on the agronomic performance and economic viability of common bean crop. The experiment was conducted in southeastern Brazil for two agricultural seasons in an area under NTS, using a split-plot in randomized complete block design. The plots represented three cropping successions (maize in sole crop, maize intercropped with Urochloa ruziziensis and U. ruziziensis in sole crop) and the subplots composed of ten combinations of splitting of top-dressing N, at the stages V3, V4 and R5 of the common bean crop. In relation to the single application of the N dose of 90 kg ha−1, the common bean had higher response as a function of the N splitting schemes adopted, regardless of the previous cropping succession. The cropping successions evaluated did not interfere with the seed yield of common bean as subsequent crop, even at the beginning of the establishment of NTS. To obtain higher seed yield and economic viability, the N dose of 90 kg ha−1 indicated for the crop must be split and applied among the phenological stages V3, V4 and R5.

A study was conducted to identify whether composted manure and straw amendments (replacement of a portion of chemical fertilizer [50% of the total nitrogen application] with composted pig manure, and straw return [all straw from the previous rice crop] combined with chemical fertilizer) compared with no fertilization and chemical fertilizer only would change the dominant species of wheat-associated weeds as well as influence their growth and seed yield in a rice (Oryza sativa L.)–wheat (Triticum aestivum L.) rotation system. The study was initiated in 2010, and the treatment effects on the species, density, plant height, shoot biomass, seed yield of dominant weeds, and wheat yields were assessed in 2017 and 2018. Fertilization significantly increased the height, density, and yield of wheat, as well as the shoot biomass of wheat-associated weeds, but decreased the weed species number. A total of 17 and 14 weed species were recorded in the experimental wheat fields in 2017 and 2018, respectively. The most dominant weed species were American sloughgrass [Beckmannia syzigachne (Steud.) Fernald] and catchweed bedstraw (Galium aparine L.), which made up more than 64% of the weed community in all treatments. When the chemical fertilizer application was amended with pig manure compost and straw return, the relative abundance of B. syzigachne significantly decreased, while the relative abundance of G. aparine significantly increased. The application of the chemical fertilizer-only treatment resulted in increases in the density, shoot biomass, and seed yield of B. syzigachne, while the composted manure and straw amendments applied together with chemical fertilizer led to significant increases in the density, shoot biomass, and seed yield of G. aparine. Consequently, further research on ways to promote greater cropping system diversity will be needed to prevent the selection of weed species that are adapted to a limited suite of crop management practices.

In order to gain an understanding of the genetic basis of traits of interest to breeders, the pea varieties Brutus, Enigma and Kahuna were selected, based on measures of their phenotypic and genotypic differences, for the construction of recombinant inbred populations. Reciprocal crosses were carried out for each of the three pairs, and over 200 F2 seeds from each cross advanced to F13. Bulked F7 seeds were used to generate F8–F11 bulks, which were grown in triplicated plots within randomized field trials and used to collect phenotypic data, including seed weight and yield traits, over a number of growing seasons. Genetic maps were constructed from the F6 generation to support the analysis of qualitative and quantitative traits and have led to the identification of four major genetic loci involved in seed weight determination and at least one major locus responsible for variation in yield. Three of the seed weight loci, at least one of which has not been described previously, were associated with the marrowfat seed phenotype. For some of the loci identified, candidate genes have been identified. The F13 single seed descent lines are available as a germplasm resource for the legume and pulse crop communities.

Greenhouse and field studies were conducted to examine the interaction of sethoxydim or fluazifop-P tank mixed with chlorsulfuron or thiameturon for selective weed control in safflower. Under greenhouse conditions, the addition of chlorsulfuron to sethoxydim or fluazifop-P slightly improved the control of green foxtail above that achieved with either herbicide alone. Control of wild oat and wild mustard was similar with the tank mixes and each herbicide alone. In the field, control of wild oat with sethoxydim or fluazifop-P was not altered by adding chlorsulfuron or thiameturon in tank mixes. Similarly, control of common lambsquarters and wild mustard with chlorsulfuron or thiameturon was not affected by adding either sethoxydim or fluazifop-P in tank mixes. Plant height, date of flowering, seed yield, and quality data indicated that safflower tolerated these herbicides applied alone or in combination. Sethoxydim or fluazifop-P tank mixed with chlorsulfuron or thiameturon provide a postemergent alternative for selective control of grass and broadleaf weeds in safflower.

Field studies were conducted to study the interaction of sethoxydim or fluazifop-P with clopyralid and/or ethametsulfuron applied as tank mixtures to canola. Control of the indicator species barley, broadbean, and wild mustard with the tank mixtures was comparable to, or sometimes better than, that attained with each herbicide alone. Canola tolerated all herbicides applied individually and all tank mixtures of these herbicides except fluazifop-P and ethametsulfuron. Tank mixtures of fluazifop-P and ethametsulfuron, with or without clopyralid included in the mixture, suppressed early growth of canola in two of four tests and reduced seed yield in one. Sethoxydim, clopyralid, and ethametsulfuron combined in tank mixtures provide an effective POST alternative for selective control of grass and broadleaf weeds in canola.

Postemergence control of broadleaf weeds in canola with DPX A7881 was studied under controlled-environment and field conditions. DPX A7881 controlled weeds of the Cruciferae family such as wild mustard, field pennycress, and flixweed, which are not controlled with existing herbicides used for weed control in canola. Weed control was better when DPX A7881 was applied at the two-leaf than at the six-leaf stage of the weeds. At the two-leaf stage, control of flixweed was achieved with 15 g ai/ha of DPX A7881; 20 to 30 g ai/ha was required for control of wild mustard and field pennycress. Control of redroot pigweed required 30 g ai/ha. Common lambsquarters was not controlled in this study with DPX A7881 up to 60 g ai/ha. Control of weeds with DPX A7881 increased canola yields in this study without altering the important quality components: oil content, 1000-kernel weight, and green seed content. DPX A7881 provides a postemergence alternative to existing herbicides for broadleaf weed control in canola.

The potential of imazethapyr as a selective herbicide in four pulse crops was investigated at Melfort, Saskatchewan in 1988 and 1989. Lentil, field pea, faba bean and annual vetch were tolerant to imazethapyr applied preemergence to a silty clay loam soil at 0.05, 0.10, 0.15, and 0.20 kg ai ha-1. Postemergence treatments above 0.05 kg ha-1, however, stunted lentil and vetch in both years. Environmental factors, the dominant weed in the experimental site, as well as timing of application strongly influenced the performance of imazethapyr. Seed yield increases observed with imazethapyr treatments, compared to metribuzin or untreated check, were greater in 1989 when wild oat was the dominant weed and moisture was not a limiting factor in the early stages of crop development, than in 1988 when field pennycress was the dominant weed. Mean seed yield for all imazethapyr treatments, compared to the check, increased 0 and 930%, 24 and 89%, 21 and 600%, and 47 and 44% in 1988 and 1989, for lentil, field pea, faba bean and vetch, respectively. Significant increases in lentil seed density, seed size, and germination were also obtained though protein content decreased 2%.

The response of Persian darnel, green foxtail, wild oat, and volunteer cereals to clethodim applied at two growth stages, and the effect of these treatments on flax yield and quality were determined in a series of field experiments in which each weed species was evaluated separately. Clethodim applied at 45 g/ha provided excellent control of Persian darnel, green foxtail, wild oat, and volunteer wheat and barley. Sethoxydim applied at 150 g/ha provided excellent control of Persian darnel, green foxtail, wild oat, and volunteer barley. Rax was tolerant at five times the recommended rate of application and was unaffected by plant growth stage at time of application. When applied at an early (2- to 3-leaf) stage, control of Persian darnel, green foxtail, wild oat, and volunteer wheat and barley was excellent at 20 g/ha. Except for Persian darnel, weed control as determined by reduction in plant dry weight, was negatively affected by growth stage at time of application. Although visible control and reduction in plant dry weight were somewhat less when clethodim was applied at the 4-to 5-leaf stage, control of each weed species was acceptable. When weight of water in plant tissue (fresh weight – dry weight) was used as a measure of living plant tissue, wild oat and volunteer barley control were unaffected by growth stage at time of application.

Imazethapyr, alone and in combination with other herbicides, was applied PPI, PRE, and POST to pinto beans to determine weed control and selectivity to the crop. All of the herbicides improved pinto bean yield as compared with the unweeded control. Imazethapyr applied PPI and POST provided excellent control of black nightshade, kochia, Russian thistle, prostrate pigweed, and redroot pigweed. Barnyardgrass control with imazethapyr ranged from 58 to 96% and increased to 98% or greater when imazethapyr was combined with metolachlor, pendimethalin, trifluralin, or EPTC. Pinto bean yield was not reduced from any herbicide treatment compared to the handweeded control.

Redstem filaree is becoming widespread and abundant on the Canadian prairies. A field study was conducted to determine the growth, development, and seed yield response of redstem filaree when grown under noncropped conditions and planted at various dates throughout the growing season in Alberta. Redstem filaree emerged within 7 to 13 d of planting with an accumulated 57 to 134 growing degree days (GDD). Flowering occurred within 46 to 65 d (327 to 779 GDD) of planting. Plants that emerged in August or later did not flower in that season and survived as winter annuals. Spring-emerging redstem filaree plants matured within 79 to 100 d (729 to 1,193 GDD). Plants that emerged in May and June attained more biomass and produced threefold more seeds than plants that emerged in July or later. Redstem filaree seed production ranged from 2,400 to 9,900 seeds/plant depending on emergence date and environmental conditions. Information from this study will assist in developing integrated management strategies for this increasingly important weed.

Field studies were conducted to identify herbicides suitable for improved control of hairy nightshade, redroot pigweed, and common lambsquarters in pinto beans. Fomesafen at 0.25 kg ai ha-1 did not adequately control these weeds. Clomazone at 0.5 kg ai ha-1 controlled common lambsquarters but only suppressed the growth of redroot pigweed and hairy nightshade. Ethalfluralin at 0.84 to 1.1 kg ai ha-1 gave excellent initial control of these weeds but did not control later flushes of hairy nightshade. Imazethapyr applied PPI or POST at 50 to 75 g ai ha-1 controlled hairy nightshade, redroot pigweed, and common lambsquarters throughout the growing season. Imazethapyr combined with ethalfluralin gave superior weed control and resulted in greater yields than the most commonly used herbicides in pinto beans in western Canada.

The tolerance of canola and wild mustard to postemergence HOE 075032 was investigated in greenhouse and field studies. In the greenhouse, the tolerance of canola to HOE 075032 applied at the 2 Ho 3-leaf stage was approximately twice the tolerance of wild mustard. In the field, HOE 075032 applied at 5 and 10 g ai/ha at the 2 to 3-leaf stage reduced wild mustard plant density and fresh weight by over 95%. Wild mustard contamination in canola seed was reduced from 45 to less than 1%. Application of HOE 075032 at 5 g/ha significantly increased canola yield and fresh weight in each year. Canola yield increases of 25, 139, and 86% were observed for the 5 g/ha treatment in 1991, 1992, and 1993, respectively. HOE 075032 could provide a postemergent alternative to the existing herbicide for wild mustard control in canola.

The interaction of DPX-A7881 and clopyralid applied as tank mixtures was studied under controlled environment and field conditions on several commonly occurring weeds in canola. Control of wild mustard and wild buckwheat was not affected by mixing these herbicides. DPX-A7881 controlled wild mustard, and clopyralid controlled wild buckwheat independently of the other herbicide. However, redroot pigweed and common lambsquarters were controlled better with DPX-A7881 plus clopyralid than with either herbicide alone. The herbicides interacted in an additive to synergistic manner on redroot pigweed depending on the rate of each herbicide. DPX-A7881 and clopyralid interacted synergistically at all rates on common lambsquarters. Plant height, date of flowering, seed yield, and quality data all indicated that canola completely tolerated DPX-A7881 and clopyralid applied alone or in combination.

The long-term effect of repeated late-fall versus early-spring imazethapyr, hexazinone, terbacil, metribuzin, dichlobenil, or chlorsulfuron treatments, when applied on dormant stands of alfalfa was investigated at three sites for weed management of alfalfa grown for seed. Dichlobenil applied at 1.2 to 2.4 kg ha−1 and chlorsulfuron applied at 11 to 22 g ha−1 in fall or spring were the only herbicides to injure alfalfa at one location. Hexazinone provided the most consistent weed control of the herbicides evaluated. Average control of Canada thistle, catchweed bedstraw, dandelion, perennial sowthistle, quackgrass, Russian pigweed, and scentless chamomile was 80%. When averaged over three sites, weed control by hexazinone resulted in a 33% increase in seed yield.

Applications of 1.6 kg ai/ha of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one] to established alfalfa (Medicago sativa L. ‘Rambler’) at the start of each growing season for 4 yr increased seed yield by 68% and controlled established dandelion (Taraxacum officinale Weber. in Wiggers ♯ TAROF) and smooth brome (Bromus inermis Leyss. ♯ BROIN). A lesser amount of metribuzin was not sufficient for smooth brome control, and a greater amount damaged the alfalfa. Hexazinone [3-cyclohexyl-6-(dimethylamino)-methyl-1,3,5-triazine-2,4(1H,3H)-dione] applied at 1.0 kg ai/ha also controlled dandelion and smooth brome and produced increases in alfalfa seed yield. Mixtures of terbacil (3-tert-butyl-5-chloro-6-methyluracil) with reduced rates of metribuzin or hexazinone controlled dandelion well, but gave only fair control of smooth brome. Alfalfa seed yield was negatively correlated with the smooth brome population.

Field experiments were conducted in 2002 and 2003 to evaluate weed control and dry bean response to fomesafen and fomesafen tank mixtures. In the first experiment, six market classes of dry bean were treated at the first trifoliate growth stage with fomesafen + nonionic surfactant (NIS) + urea ammonium nitrate solution (UAN) at rates ranging from 210 to 840 g/ha. In the second experiment, fomesafen + NIS + UAN at 280 g/ha was applied alone or combined with imazamox at 36 g/ha, bentazon at 560 g/ha, or clethodim at 140 g/ha, and each treatment was applied postemergence at either the unifoliate, first trifoliate, or third trifoliate growth stage to six dry bean cultivars. Crop injury from fomesafen in the form of stunting and leaf crinkling was apparent 7 d after treatment (DAT), but crop injury was temporary and plants recovered. Common lambsquarters and hairy nightshade control increased from 61 to 71% and 74 to 92%, respectively, as fomesafen rate increased from 210 to 280 g/ha. Redroot pigweed, kochia, and common purslane were controlled at the ≥90% level by fomesafen at 210 g/ha. Applying fomesafen and fomesafen tank mixtures at the unifoliate growth stage caused less dry bean injury and improved redroot pigweed, common lambsquarters, and hairy nightshade control compared with treatments made at the first or third trifoliate growth stage. Decreased weed control caused by delaying herbicide application to the third trifoliate growth stage resulted in a 17% decrease in crop yield, compared with treatments where herbicides were applied at the unifoliate growth stage. Combining fomesafen with other herbicides increased crop injury 4%, 14 DAT. A tank mixture of fomesafen plus imazamox caused more crop injury than fomesafen plus bentazon. Combining fomesafen with imazamox or bentazon improved hairy nightshade control to 92 and 87%, respectively; however, common lambsquarters control was improved only with tank mixtures of fomesafen with bentazon.

Farmers grow crops in the dryland region of the Pacific Northwest (PNW) using tillage practices ranging from moldboard plowing to no-tillage. The objective of this study was to determine the effect of tillage on persistence of imazamox herbicide in intermediate and high precipitation zones of the inland PNW. Along with a nontreated control, imazamox was applied to imidazolinone-tolerant winter wheat in the fall and spring at one, two, and three times the maximum labeled rate at locations near Genesee, ID, Davenport, WA, and Pendleton, OR. Moldboard plow, chisel plow, and no-till tillage treatments were implemented soon after wheat harvest and yellow mustard was planted the following season to determine crop response. Experiments were conducted at each location in 2005 to 2007 and 2006 to 2008. There were significant location by year and year and location interactions. There was no significant tillage by imazamox rate interaction, except at Pendleton in year 2, for all measured yellow mustard responses (crop injury, biomass, and yield). Genesee was colder than Pendleton and had more precipitation than Davenport, resulting in more injury to yellow mustard at Genesee than at Pendleton but less than at Davenport. Davenport had greater injury than the other two locations, likely due to lower soil pH, higher organic matter (OM), and cooler, drier climate, which allowed imazamox to persist longer in the soil. Overall, Pendleton had the least yellow mustard injury, which likely was related to its warmer, wetter climate and the concomitant rapid soil dissipation of imazamox. Tillage did not reduce the persistence of imazamox. Yellow mustard had the lowest injury and had greater mature biomass and seed yield in no-till seeded plots when averaged across imazamox rates compared to moldboard and chisel-plowed plots.

Blessed thistle is an important medicinal crop in Europe and recently has become more significant in North America. A limiting factor in blessed thistle production is weed interference. Field experiments were conducted near Plovdiv, Bulgaria, to study the effect of selected herbicides on weed control, crop productivity, and crop quality. Seed yields of blessed thistle were increased with metribuzin alone at 0.5 kg ai/ha, pendimethalin alone 1.32 kg ai/ha, pendimethalin at 1.32 kg ai/ha plus metribuzin at 0.5 kg ai/ha, trifluralin at 0.84 kg ai/ha plus linuron at 1.0 kg ai/ha, and in the hand-weeded control compared to the nonweeded control (nontreated check). Pendimethalin and metribuzin were safe both alone and in combination for weed control in blessed thistle. Bentazon at 0.96 kg ai/ha inhibited blessed thistle development and reduced seed yields compared to the untreated check. Generally, weed control increased the content of silymarin and decreased the amount of seed oil. Overall, seeds contained 0.26 to 0.36% taxifolin, 0.69 to 0.99% silydianin plus silycristin, 1.31 to 1.78% silybin, and 0.27 to 0.39 % isosilybin.

Desiccants are currently used to improve lentil dry-down prior to harvest. Applying desiccants at growth stages prior to maturity may result in reduced crop yield and quality, and leave unacceptable herbicide residues in seeds. There is little information on whether various herbicides applied alone or as a tank-mix with glyphosate have an effect on glyphosate residues in harvested seed. Field trials were conducted at Saskatoon and Scott, Saskatchewan, Canada, from 2012 to 2014 to determine whether additional desiccants applied alone or tank mixed with glyphosate improve crop desiccation and reduce the potential for unacceptable glyphosate residue in seed. Glufosinate and diquat tank mixed with glyphosate were the most consistent desiccants, providing optimal crop dry-down and a general reduction in glyphosate seed residues without adverse effects on seed yield and weight. Saflufenacil provided good crop desiccation without yield loss, but failed to reduce glyphosate seed residues consistently. Pyraflufen-ethyl and flumioxazin applied alone or tank mixed with glyphosate were found to be inferior options for growers as they exhibited slow and incomplete crop desiccation, and did not decrease glyphosate seed residues. Based on results from this study, growers should apply glufosinate or diquat with preharvest glyphosate to maximize crop and weed desiccation, and minimize glyphosate seed residues.

A chickpea collection of 1600 desi and 1400 kabuli were evaluated for yield losses arising from pod borer (Helicoverpa armigera) infestation under rainfed conditions by spraying half the plots to prevent pod borer infestation and allowing the other half to be infested. From these lines, 82 were selected for further detailed evaluation of Helicoverpa resistance and drought resistance under irrigated and rainfed conditions. The yield losses from Helicoverpa damage varied from 10 to 33% depending on the chickpea type and the growing environment. Spreading types were more susceptible to Helicoverpa damage than erect types, as were kabuli types compared to desi types. Yield losses due to Helicoverpa infestation were always greater in the irrigated than in the rainfed materials. Terminal drought reduced yields by 13–37% depending on plant type. The yields in the kabuli c“hickpea lines were more severely reduced than were the desi types, due to a greater reduction in the number of branches and pods per plant in the kabuli compared to the desi lines. It appears that the extent of pod borer damage varies between the chickpea types, and that desi types have greater drought resistance than kabuli ones. These characteristics should be informative for the population improvement of chickpea for environments in which terminal drought and Helicoverpa damage occur frequently.