Genetic Variation in Yellow Nutsedge (Cyperus esculentus)

Weed Science ◽  
1987 ◽  
Vol 35 (4) ◽  
pp. 506-512 ◽  
Author(s):  
Michael J. Horak ◽  
Jodie S. Holt ◽  
Norman C. Ellstrand

Genetic diversity within and among populations of yellow nutsedge (Cyperus esculentusL. # CYPES) was analyzed to evaluate and quantify the genetic consequences of the reported predominance of asexually-produced tubers as colonizing agents. Ten populations were examined using starch gel electrophoresis for allozyme analysis. Four populations of purple nutsedge (Cyperus rotundusL. # CYPRO) were surveyed for comparison. Twelve loci were identified in yellow nutsedge among the eight enzyme systems examined; ten of these loci were found in purple nutsedge. Yellow nutsedge showed relatively low genetic diversity. Most of the genetic diversity occurred as differences among individuals within populations (Hs), compared to differences among populations (Dst) for the four variable loci identified in this species. Thus, most genetic distancesbetween its populations were small. Generally, only a few genotypes occurred within each population. Purple nutsedge was found to possess even lower within- and among-population gene and genotypic diversity. This study supports the view that tubers account for most of the establishment of new populations of both species.

Weed Science ◽  
1968 ◽  
Vol 16 (3) ◽  
pp. 339-340 ◽  
Author(s):  
W. S. Hardcastle ◽  
R. E. Wilkinson

Purple nutsedge (Cyperus rotundus L.) and yellow nutsedge (Cyperus esculentus L.) tubers were stored at 5 C in soil treated at 0, 2, 3, 4, 6, 8, or 10 lb/A 2,6-dichlorobenzontrile (dichlobenil) for 2, 4, 6, 8, 10, or 12 weeks. Respiration of dormant tubers differed with species, unaffected by period of storage or dichlobenil concentration. Sprouting of untreated tubers decreased from 90% after 2 weeks storage to 43% after 12 weeks. Yellow nutsedge sprout production was uniform in time; purple nutsedge sprouting progressed to an 8-week high. Increased concentrations of dichlobenil progressively inhibited sprouting.


Weed Science ◽  
1971 ◽  
Vol 19 (5) ◽  
pp. 601-606 ◽  
Author(s):  
P. E. Keeley ◽  
R. J. Thullen

Nonradioactive and14C-labeled arsenical herbicides were applied to foliage of purple nutsedge (Cyperus rotundusL.) and yellow nutsedge (Cyperus esculentusL.) grown under greenhouse and growth chamber conditions. Disodium methanearsonate (DSMA) controlled purple nutsedge better at 20 and 29 C than at 13 C. Monosodium methanearsonate (MSMA) was as effective in controlling this weed at 13 C as at 20 and 29 C. DSMA and MSMA provided 80% or greater control of yellow nutsedge grown at the three temperatures. When plants were treated with14C-DSMA and14C-MSMA, greater radioactivity was detected in yellow nutsedge than in purple nutsedge. The apparent differential herbicide penetration of purple and yellow nutsedge leaves is believed to have contributed substantially to the control of nutsedge observed in this study.


Weed Science ◽  
1972 ◽  
Vol 20 (1) ◽  
pp. 71-74 ◽  
Author(s):  
P. E. Keeley ◽  
C. H. Carter ◽  
J. H. Miller

The following herbicides were evaluated for relative phytotoxicity to cotton(Gossypium hirsutumL. ‘Acala SJ-1′), purple nutsedge(Cyperus rotundusL.), and yellow nutsedge(Cyperus esculentusL.) under greenhouse conditions: 2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide (alachlor); 2-chloro-2′,6′-diethyl-N-(butoxymethyl)acetanilide (CP-53619); 2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione (VCS-438); 4-chloro-5-(dimethylamino)-2-α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone (San-6706); 2-(α naphthoxy)-N,N-diethyl-propionamide (R-7465); andS-isopropyl 5-ethyl-2-methyl-piperidine-1-carbiothioate (R-12001). Herbicides were incorporated 6.35 cm deep, at rates of 1.12, 2.24, and 4.48 kg/ha, into a fine sandy loam prior to planting. All treatments except the low rate of alachlor and VCS-438 controlled yellow nutsedge for 8 weeks. R-7465 and R-12001 at 1.12 kg/ha and San-6706 at 2.24 kg/ha controlled purple nutsedge for 8 weeks. Alachlor and CP-53619 were somewhat less effective against purple nutsedge than yellow nutsedge, but their intermediate rates suppressed purple nutsedge for 4 weeks. Even the high rate of VCS-438 was ineffective against purple nutsedge. Cotton, in terms of fresh shoot weight, exhibited considerable tolerance to 1.12 and 2.24 kg/ha of VCS-438 and CP-53619 and 1.12 kg/ha of R-7465. Applications of 2.24 kg/ha of CP-53619 and 1.12 kg/ha of R-7465, however, suppressed the development of lateral roots of cotton. Other rates of these herbicides and all rates of alachlor, R-12001, and San-6706 moderately to severely injured cotton in most of the experiments.


Weed Science ◽  
2008 ◽  
Vol 56 (5) ◽  
pp. 735-742 ◽  
Author(s):  
Theodore M. Webster ◽  
Timothy L. Grey ◽  
Jerry W. Davis ◽  
A Stanley Culpepper

The phase-out of methyl bromide requires alternative nutsedge management options in vegetable systems. Options that target tuber production, the primary means of reproduction, will be most beneficial. A study was conducted to evaluate the response of purple nutsedge and yellow nutsedge foliar growth and tuber production to a range of glyphosate rates. Glyphosate was applied at six rates between 0.41 and 2.57 kg ae ha−1to 5-wk-old nutsedge plants with multiple shoots. The rate of glyphosate needed to reduce growth 50% (I50) was similar for purple nutsedge foliar growth (0.58 kg ha−1) and tuber biomass (0.55 kg ha−1). In contrast,I50for yellow nutsedge foliar growth was 0.73 kg ha−1, which was greater than theI50for tuber biomass (0.41 kg ha−1). First-order tubers, those directly attached to the initial tuber, had anI50of 0.70 and 0.44 kg ha−1of glyphosate for purple nutsedge and yellow nutsedge tuber biomass, respectively. For all higher-order tubers,I50values ranged from 0.29 to 0.60 and 0.14 to 0.30 kg ha−1of glyphosate for purple nutsedge and yellow nutsedge tuber biomass, respectively. Glyphosate at 0.74 kg ha−1prevented fourth-order purple nutsedge and third-order yellow nutsedge tuber production (terminal tubers for yellow nutsedge). Fifth- and sixth-order purple nutsedge tuber production was eliminated by the lowest tested rate of glyphosate (0.41 kg ha−1). Effective nutsedge management options will require consistent control between spring and autumn crops. Glyphosate is economical, poses no herbicide carryover issues to vegetables, and minimizes nutsedge tuber production; therefore, it is a suitable candidate to manage nutsedges.


1994 ◽  
Vol 24 (6) ◽  
pp. 1123-1132 ◽  
Author(s):  
P.D. Khasa ◽  
W.M. Cheliak ◽  
J. Bousquet

Racospermaauriculiforme (Cunn. ex Benth.) Pedley and Racospermamangium (Willd.) Pedley are two fast-growing multipurpose leguminous species that have great potential for reforestation in the subhumid and humid tropics. The level and distribution of genetic variability were evaluated among and within 13 populations of each species at 18 loci encoding 10 enzymes, using starch gel electrophoresis. At the population level, the mean number of alleles per locus, the mean percentage of polymorphic loci, and mean expected heterozygosity were, respectively, 1.9, 52.1%, and 0.122 for R. auriculiforme, and 1.5, 24.3%, and 0.064 for R. mangium. Therefore, R. mangium appeared genetically depauperate compared with R. auriculiforme. The proportion of the total genetic diversity that resided among populations in R. auriculiforme (18%) was twice that in R. mangium (9%). No linear relationships were detected between genetic and geographic distances among populations. Cluster analysis of Nei's genetic distances and discriminant analysis did not show any significant geographic pattern of population differentiation for R. mangium. These same analyses revealed two distinct clusters of populations for R. auriculiforme, one in Queensland, Australia, and Papua New Guinea, and the other in the Northern Territory of Australia and Indonesia. For both taxa, seed of unknown origin of some introduced populations in Zaire and Congo could be identified. The genetic distance between the two species (D = 0.097) was, as expected, much larger than the average intraspecific genetic distance derived from comparisons of conspecific populations (D = 0.034 for R. auriculiforme and D = 0.007 for R. mangium). However, the amplitude of the interspecific genetic distance calculated is representative of divergence levels usually observed among subspecific taxa. Based on this, and the lower levels of genetic diversity found in R. mangium, it is suggested that R. mangium derived recently from R. auriculiforme.


2016 ◽  
Vol 30 (3) ◽  
pp. 743-750 ◽  
Author(s):  
Thomas V. Reed ◽  
Nathan S. Boyd ◽  
Peter J. Dittmar

Purple and yellow nutsedge are problematic weeds in Florida small fruit and vegetable production. EPTC and fomesafen are PRE herbicides that suppress both nutsedge species, but field application in Florida has shown control to be erratic. Greenhouse experiments were conducted in Gainesville, FL, from May to August 2014 and in Wimauma, FL, from March to May 2015 to investigate susceptibility of purple and yellow nutsedge to EPTC and fomesafen applications. Treatments included EPTC at 2.91 kg ai ha−1and fomesafen at 0.42 kg ai ha−1at 0, 3, 6, 9, 12, and 15 d after planting (DAP) tubers, plus a nontreated control. EPTC and fomesafen applications averaged across timings decreased purple and yellow nutsedge emergence, shoot height, leaf number, and shoot mass compared to the nontreated control. Herbicide applications 0 DAP reduced purple nutsedge emergence greater than 65% compared to the nontreated control and caused at least 74% injury 4 wk after planting. Herbicide applications 0 DAP decreased yellow nutsedge emergence and shoot mass compared to the nontreated control by at least 86 and 93%, respectively. Applications of EPTC and fomesafen have the ability to suppress short-term purple and yellow nutsedge growth. Applications made at or prior to tuber sprouting maximize herbicide efficacy.


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