New sources of midge (Stenodiplosis sorghicola) resistance among local Sorghum bicolor cultivars were determined in experiments carried out from 1996-99 in Burkina Faso. Two hundred local landraces from Burkina Faso and other West African countries were screened for midge resistance. The 40 best cultivars were tested with resistant and susceptible controls during the 1999 rainy seasons, in midge-infested sites Kouaré and Farako-Bâ. The average percentage of midge-damaged spikelets in Kouaré varied from 0% in ICSV 745 to 45.3% in susceptible landrace 439. At Farako-Bâ, the percentage of damaged spikelets varied from 0.4% in ICSV 745 to 31.8% on the susceptible control Sariaso 10. Cultivar Tenlopieno had the highest percentage of damaged spikelets in both locations, but showed low visual midge damage scores

Ba, M

Da, S

Dakouo, D

Ratnadass, A

Trouche, G

ICRISAT Open Access Repository

carried out to evaluate suitable weed managementpractices for a sorghum-based intercropping system. Thetrial was conducted under irrigated conditions at theAgricultural College and Research Institute, Killikulamduring the summer and winter seasons of 1997. The soil inthe experimental field was a sandy clay loam with a pH of7.4, low in available nitrogen (153.6 kg N ha-1), with a moderate level of available phosphorus (12.3 kg P2O5ha-1)and high in available potassium (282.5 kg K2O ha-1). Theweed flora found in the experimental field included thegrasses: Eleusine indica L., Dactylocatenium aegyptium Beav., Echinochloa colonum L., and Cynodon dactylon L.,the sedge Cyperus rotundus L., and the broadleavedweeds: Trianthema portulacastrum L., Trianthema monogyna L., Boerhaavia diffusa L., Phyllanthus niruri L.,Phyllanthus maderaspatersis L., Digera arvensis Forsk,and Cynotis cucullata L. Experiments were laid out in a split-plot design with three replicates. Three croppingsystems were the main plots and seven weed managementpractices the subplots.Sole-crop sorghum cv CO 26 was sown at a spacing of45 x 15 cm. For the intercrops, sorghum was sown inpaired rows (60/2 x 15 cm). Black gram [ Vigna mungo (L.)Hepper] cv CO 5 (30 x 10 cm) and cowpea [Vigna unguiculata (L.) Walp.] cv CO 4 (30 x 20 cm) were sown inbetween pairs of sorghum rows in an additive series at a ratio of 2:1. Fertilizer was applied at the recommendedrate of 90 N:45 P:45 K kg ha-1. Weed control treatments areindicated in Table 1. Al l herbicides were sprayed 3 daysafter sowing (DAS) with knapsack sprayers fitted withflood-jet nozzles using 500 L of water.ResultsWeed dry matter, weed control efficiency, yieldparameters, and sorghum yields were significantlyaffected by both intercropping systems and weedmanagement practices. Among the intercropping systems,intercropping of sorghum and cowpea in a 2:1 ratio causeda significant reduction in weed dry matter production andhad a higher weed-smothering efficiency than othertreatments (Table 1).The sole sorghum crop recorded higher weed drymatter, lower weed-smothering efficiency, and suchhigher yield parameters as panicle length, number ofgrains panicle-1, 1000-grain mass, and grain yield than theintercrops. Among the weed management practices, theunweeded control had higher weed dry matter, and lowercrop yield parameters and yield than the other treatments.Metolachlor (1.0 kg ha-1) plus hoeing at 40 DAS resultedin low weed dry matter, higher weed-smotheringefficiency, and maximum crop yield parameters and yield.This treatment was followed by isoproturon (0.6 kg ha-1)plus hoeing at 40 DAS. The interactions betweenintercropping systems and weed management practiceswere significant. Highest intercrop yields (black gram andcowpea) were recorded following the metolachlor (1.0 kgha-1) plus hoeing at 40 DAS treatment. The highest landequivalent ratio (LER) was recorded in the sorghum + black gram intercropping system. Applications ofmetolachlor (1.0 kg ha-1) plus hoeing at 40 DAS resulted ina high LER. It can be concluded that an intercrop ofsorghum with black gram treated with metolachlor is thebest way to achieve maximum yield and monetary returnunder the conditions of the experiment.ReferencesLopez, J.A. and Galetto, A. 1983. Effect of weed competition atdifferent stages of crop growth in sorghum. Malezas 11: 52-72.(Spanish) Efecto de competencia de malezas en distintos estadosde crecimicnto del sorgo. Malezas 11: 52-72.Pests and DiseasesNew Sources of Resistance to SorghumMidge in Burkina FasoD Dakouo1, G Trouche2,4, A Ratnadass3,4, M Ba1,and S Da1 (1. Institut d'etudes et de recherchesagricoles (Burkina Faso) (INERA), Station deFarako-Ba, BP 910 Bobo-Dioulasso, Burkina Faso.2. INERA/Centre de cooperation internationale enrecherche agronomique pour le development(CIRAD), Station de Saria, BP 10 Koudougou,Burkina Faso. 3.ICRISAT-CIRAD, BP 320 Bamako,Mali. 4. CIRAD-CA, Programme CALIM, TA 73/09,34398 Montpellier Cedex 5, France)IntroductionSorghum [Sorghum bicolor(L.) Moench] is the main cerealcrop in Burkina Faso, with an average annual productionduring 1992-94 of 1.25 million tons (FAO and ICRISAT,1996). The major biotic constraints to its cultivation areinsect pests, diseases, and Striga spp. The sorghum midge(Stenodiplosis sorghicola Coquillett) is the most importantpest of the crop in the southern, central, and easternregions of the country (Bonzictal. 1984;Nwanze 1988). A survey conducted in eastern and central regions in 1999,revealed that farmers have to grow early-maturing redsorghum or other cereal crops maize (Zea mays L.) andpearl millet [Pennisetum glaucum (L.) R. Br.] in order to34 ISMN 41,2000avoid the midge problems they experience on late-maturing sorghum. To reduce infestation and losses, themost appropriate and sustainable insect control strategyfor subsistence farmers is based on insect-resistantcultivars combined with cultural practices. However,resistant varieties developed on other continents byscientists, including those working at internationalagricultural research centers, have not solved midgeproblems in most African countries. Such resistantvarieties turned out to be susceptible to such other bioticconstraints as foliar diseases, grain molds, and head bugs(Eurystylus oldii Poppius) that eventually translated intopoor grain quality for traditional dishes like to. In addition,breakdown of resistance to sorghum midge in suchvarieties has been reported from Kenya (Sharma et al.1999). It is therefore critical to develop midge-resistantvarieties that are well-adapted to African conditions, andtolerant to other biotic constraints. Alternative ways ofbreeding for midge resistance include crossing exotic orlocal sources of resistance with high-yielding and well-adapted varieties. This paper reports the results of a searchfor new sources of midge resistance among local sorghumcultivars, carried out from 1996-99 in Burkina Faso.Materials and methodsMore than 200 local landraces from Burkina Faso andother West African countries were screened under naturalmidge infestation. The best 40 varieties selected for theirlow midge damage scores, were tested along with 10susceptible and resistant controls during the 1999 rainyseason, in a randomised complete-block design with tworeplications. The experiment was carried out at twolocations known to be midge 'hot-spots', namely Kouare(eastern region) and Farako-Ba (western region). Thevarieties were sown in 10-m long, single-row plots.Spacing between rows was 0.8 m and within rows, 0.40 m.Border lines of a susceptible variety were sown 15 daysbefore the test cultivars as 'infestor rows', in order toincrease natural midge populations. Local landrace 439and improved variety Sariaso 10 were used as susceptiblecontrols while ICSV 745 (Sharma et al. 1992) was used asa resistant control. Plots were thinned to one plant per hill.Fertilizer was applied as follows: 100 kg ha-1 of a complexNPK (14:23:14) at thinning, and 50 kg ha-1 of urea (46%N) at panicle initiation. Time to 50% anthesis wasrecorded. Midge damage was evaluated as described bySharma et al. (1992). Data was expressed as thepercentage of midge-damaged spikelets based on theobservation of 500 spikelets per plot. At crop maturity,midge damage was evaluated by visually rating five plantsper plot, using a 1-9 scale (Sharma et al. 1992) where 1 = less than 10%, and 9 = more than 80% chaffy spikelets.Data were subjected to analysis of variance after arcsinetransformation, using STATITCF software (ITCF 1991).Results and discussionResults obtained on the best 10 varieties, namely thosecombining a midge incidence of less than 10% damagedspikelets, and a visual score of less than 2 at both locations,are given in Table 1. Time to 50% anthesis varied withlocations and ranged from 49 days (cultivar 533) to 92days (G 1645). The average percentage of midge-damagedspikelets varied at Kouare' from 0% (ICSV 745) to 45.3%(susceptible control landrace 439). At Farako-Ba, thepercentage of damaged spikelets ranged from 0.4% onICSV 745 to 31.8% on the improved variety Sariaso 10used as a susceptible control. Visual scores varied from 1 (ICSV 745) to 2.6 (G 1645) on resistant entries at Kouare,while at Farako-Ba, they ranged from 1 (ICSV 745) to 1.7(Tenlopieno). On susceptible controls, visual scores variedfrom 7 to 9 at Kouare and from 3.9 to 4.3 at Farako-Ba.Tenlopieno (originating from eastern Burkina) showed thehighest percentage of damaged spikelets both at Kouareand Farako-Ba with an average of 15.5% over 3 years oftests (1996-98). However, this cultivar showed low visualmidge damage scores (1.2 and 1.7); in addition, it istolerant of E. oldii damage. Wanmiougou and G 1647showed low and stable midge damage scores acrosslocations. In 1999, their damage ratings were 0.5% forKouare, and 1.5% and 3.5% at Farako-Ba; the averagedamage ratings over 3 years were 1.1% at Kouarte and0.1 % at Farako-Ba. Visual scores varied from 1 to 1.4 atboth locations. It should further be noted that sources ofresistance to midge were identified within varioussorghum races. These results obtained over 4 years of testsunder high natural midge infestations constitute animportant step in breeding for resistance to midge usinglocal sources of resistance. Further investigations will beconducted under artificial infestation to elucidate themechanisms of resistance to sorghum midge that areinvolved in each variety.AcknowledgementsThis research work was supported from 1997 by theEuropean Union-funded Project INCO-DC 18-CT96-0106. The authors thank H C Sharma for reviewing themanuscript; they also thank J Sanou, B Sanou, B Dembele,P Yameogo, and A Zongo for technical assistance incarrying out experiments at both locations.ReferencesBonzi, S.M., Doumbia Y.O., and Dakouo D. 1984. Lac6cidomyie du sorgho, Contarinia sorghicola, en Afrique deISMN 41,2000 3536 ISMN 41,2000I'Ouest. Synthese des travaux realises de 1961 a 1984. Premierseminaire de lutte integree contre les principaux ravageurs descultures vivrieres, 4-8 Dec. 1984, Niamey, Niger. Ouagadougou,Burkina Faso: Direction Regionale du Projet CILSS/FAO/USAID de lutte integree. 9 pp.FAO and ICRISAT. 1996. The world sorghum and milleteconomies: Facts, trends and outlook. Rome, Italy: Food andAgriculture Organization of the United Nations (FAO) andPatancheru 502 324, Andhra Pradesh, India: International CropsResearch Institute for the Semi-Arid Tropics (ICRISAT), 72 pp.ITCF. 1991. STAT-ITCF Version 5. Manuel d'utilisation.Nwanze, K.F. 1988. Distribution and seasonal incidence of somemajor insect pests of sorghum in Burkina Faso. Insect Scienceand Its Application 9: 313-321.Sharma, H.C., Taneja, S.L., Leuschner, K., and Nwanze, K.F.1992. Techniques to screen sorghums for resistance to insectpests. Information Bulletin no. 32. Patancheru 502 324, AndhraPradesh, India: International Crops Research Institute for theSemi-Arid Tropics. 48 pp.Sharma, H.C., Mukuru, S.Z., Manyasa, E., and Were, J.W.1999. Breakdown of resistance to sorghum midge, Stenodiplosis sorghicola. Euphytica 109: 131-140.Inheritance of Resistance to Sorghum Midgeand Leaf Disease in Sorghum in KenyaH C Sharma1, S Z Mukuru2, H Gugi2, andS B King2 (1. International Crops Research Institutefor the Semi-Arid Tropics (ICRISAT), Patancheru502 324, Andhra Pradesh, India; and 2. ICRISATPO Box 39063, Nairobi, Kenya)IntroductionSorghum [Sorghum bicolor(L.) Moench] is one of the mostimportant cereal crops in the semi-arid tropics (SAT). Ofthe over 150 species of insects that damage the sorghumcrop, the sorghum midge (Stenodiplosis sorghicola Coquillett), is the most important pest in the Lake Victoriabasin area of eastern Africa. Leaf diseases such asanthracnose [Colletotrichum graminicola (Cesti.) Wilson],zonate leaf spot [Gloeocercospora sorghi (Bains andEdgerton)], leaf blight [Exserohilum turcicum (Pass.)Leonard and Suggs.], and rust (Puccinia purpurea Cooke)also constitute important constraints to increasing theproduction and productivity of sorghum in this region.Nearly 15,000 sorghum germplasm accessions havebeen screened for resistance to sorghum midge at theInternational Crops Research Institute for the Semi-AridTropics (ICRISAT), Patancheru, India; and 25 lines havebeen found to be resistant across seasons and locations inIndia (Sharma et al. 1993). Most of the high-yielding,midge-resistant lines derived from cv DJ 6514 have showna susceptible reaction to sorghum midge at Alupe, Kenya(Sharma et al. 1998). To investigate the interactionsbetween midge-resistant and midge-susceptiblecytoplasmic male-sterile (cms) lines and restorers forexpression of resistance to sorghum midge and leafdiseases, a set of 36 F1 hybrids and their parents [12restorers showing resistance to sorghum midge in India,and three cms lines (ICSA 88019 and ICSA 88020—resistant to sorghum midge in India, and ICSA 42—asusceptible control)] were tested at Alupe, Kenya in 1994to determine whether the restorers showing resistance tosorghum midge/leaf diseases combined with the cms linesto produce hybrids with resistance to these pests. Suchinformation is important when selecting parents fortransferring resistance into high-yielding varieties andhybrids to increase the production and productivity ofsorghum in eastern Africa.Materials and methodsGene action for sorghum midge resistance was studied ontwo midge-resistant (ICSA 88019 and ICSA 88020)(Agrawal et al. 1996) and one commercial midge-susceptible (ICSA 42) cms lines. Twelve genotypesidentified as resistant to sorghum midge in India (Sharmaet al. 1993) were used as restorers. Thirty-six F1 hybridsand their parents were sown in a randomized completeblock design at Alupe, Kenya during the 1994 short rainyseason, in three replications. Each entry was sown in a 4-mlong, two-row plot. The experiment was sown twice at aninterval of 10 days to avoid escapes, and maximize insect/disease incidence on the crop. The crop was raisedfollowing normal agronomic practices. No insecticide wasapplied during the reproductive phase of the crop. Atmaturity, the panicles were evaluated visually for sorghummidge damage (damage rating, DR) on a 1 to 9 scale (1 = <10%, 2 = 11-20%, 3 = 21-30%, 4 = 31-40%, 5 = 4 1 -50%, 6 = 51-60%, 7 = 61-70%, 8 = 71-80%, and 9 = >80% midge-damaged spikelets). Leaf disease(anthracnose, rust, leaf blight, and zonate leaf spot)severity (LDS) was evaluated on a 1 to 9 scale (1 = <10%,2 = 11-20%, 3 = 21-30%, 4 = 31-40%, 5 = 41-50%, 6 = 51-60%, 7 = 61-70%, 8 = 71-80%, and 9 = >80% of theleaf area infected). Overall LDS was recorded in both thesowings, while individual LDS was recorded only in firstsowing, when the LDS was greater than that in the secondsowing. The material was also evaluated for agronomicdesirability (agronomic score, AS) on a 1-5 scale (1 = agronomically desirable phenotype with high yieldISMN 41,2000 37

New sources of resistance to sorghum midge in Burkina Faso

http://oar.icrisat.org/1902/1/ISMN41_34-37_2000.pdf

New sources of resistance to sorghum midge in Burkina Faso

Abstract

Similar works

Full text

Available Versions

ICRISAT Open Access Repository