The effects of sowing dates and plant densities on charcoal rot development in sorghum cultivars grown under recedingsoil moisture and natural infection conditions were studied during two postrainy seasons at four locations in India. In both the seasons, maximum charcoal rot infection (as measured by lodging) occurred in the first sowing. Significant (P <0.05) differences were recorded in charcoal rot incidence among the test cultivars, and E 36-1 from Ethiopia was resistant at all locations. High incidence of lodging was recorded even in a population of 133,350 plants ha -1 and this plant density was found to be adquate to quantify genotypic differences in lodging. Lodging was significantly (P < 0.05) correlated with soft stalk, number of nodes crossed, root damage and plant senescence

Karunakar, R I

Mughogho, L K

Pande, S

ICRISAT Open Access Repository

- 3  \34$ Indian J. Plant Prot. 20:162-170,1992. Incidence of charcoal rot in sorghum cultivars as affected by sowing date and plant density S. PANDE, L.K. MUGHOCHO AND R.I. KARUNAKAR Indian J. Plant Prot. 20T62-370,1992. Incidence of charcoal rot in sorghum cultivars as affected by sowing date and plant density S. PANDE, LK. MUGHOGHO AND R.I. KARUNAKAR Cerals Program, Intmtionnl Crops Rrsdatrh Institute for the Semi-Arid Tropics (ICRISAT), Patandrm, Andhm Pmdesh, 502 324. ICRISATjournal Article No. 1344. A B S T R A C T  The effects of sowing dates and plant densities on chatcoal rot development in sorghumcultivangrownunder~dingsoil moisturemd natural infection conditions were studied during two postniny reasons at four locations in India. In both the seasons, maximum charcoal rot infection (as measured by lodging) occurred in the first sowing. Significant (P<0.05) differences were recorded in charcoal rot incidence among the test cultivars,and E36-1 from Ethiopia was rcsistmt at all locations. High incidence of lodging was recorded even in a population of 133,350 planls ha -1 and this plant density was found to be adquate to quantify genotypic differences in lodging. Lodging was signifiantly (P < 0.05) correlated with soft stalk, number of nodes crossed, root damage and plant senescence. Introduction Charcoal rot of sorghum (Sorghum bicolor(L.) Moench),caused by Macrophominaphaseolina (Tassi) Goid, is a major disease in the postrainy season(Anahosurand Patil,l981). Thc disease occurs most often when plants are drought stressed during grain filling (Edmunds 1964,Odvody and Dunkle, 1979). Sorghum grown at close spacings had a higher incidence of charcoal rot than a widerspaced crop (Wadsworth and Sieglinger, 1950). Patil ct al. (1982) observed cultivar differences in the incidence of charcoal rot at different plant densities. A higher incidenceof charcoal rot was noted in sorghum cultivars sown in September than in October sowings (Anahosur and Patil, 1981 1. Data on the combincd effects of these factors and their interactions on charcoal rot development are not available. In this paper we report the effect of sowing data,  plant densities, and a combination of factors that are most likely to favour charcoal rot development under natural infection conditions. Materials and Methods Expcrimcn ts were conducted during the postrainy season at four sites (Patancheru, Nandyal and Madhira in Andhra Pradesh and Dharwad in Karnataka) in 1981-82, and at two sitcs (Patanchcru, and Dharwad) in 1982-83on fields(Vertisolsand Alfisols) with previous histories of charcoal rot epidemics. The test genotypes includcd local landraces: E 36-1 (IS 304691, Anncgeri-1 and M 35-1 (Maldandi), and improved cultivars: SPV 422, SPV 424, and CSH 6. Theexperiments wereconducted in spli t- spli t-plot dcsign in 1981-82 and split-plot dcsign in 1982-83 in a plot size of 4 X 4.5 m with three replications. The main plots were assigned to sowing dates and test cultivars Incidence of charcoal rot in sorghum 163 to sub-plots. In the 1981-82 season, the sub- subplotshad three plant populationdensities (Dl = 66,675, D2 = 133,350 and D3 = 266,700 plants ha -1. As cqually severe charcoal rot developed in thc 1981-82 season in both q and Dj plantingdensitics(Table2), thercfore,in 1982- 83 season expcrimcnt was r a i d  only at 133,350 plants ha-1. Sowings tvcre donc at the end of the rainy season, the first sowing coincided with thc local farmers' sowing time. Succcssivc sowings wcrc done at intervals of 7-20 days, depending upon the rainfall distribution. In the absence of sufficient rainfall, expcriemcnts wcre irrigated (10L4rows-1 of4mlcngth)initially after sowings, toget uniform cmcrgenceand crop stand. No supplementary irrigation was given after emergence and the crop was left to grow under natural conditions. All sowings r t~eivcd 40 kg N and P205 ha-1 as basal fertilizer and urca 0 40 kg ha-1 was applied as a top dressing 30 days after emcrgcnce and thinning. To protect the crop from shoot fly and stcm borer darnage, carbofurangranulcs wercapplicd @ 15g4m- 1 row lcngthatsowing,followcd by inlcnsivc sprays of cndosulfan (035% a.i.) at 10-day intervals from 30 days aftcr emergence to flowering. Seven days aftcr physiological maturity charcoal rot parameters (lodging, soft stalk, progrcss of infection up thc stalk (calcula tcd as number of nodcs crossed), root infection, and plant senesccncc) wcrcrccordcd on cach plant in thc four center rows in cach plot. Total plan tsineach plot wcrecountcd before theinitiationof loding. Thenumbcrof lodgcd and soft-stalked plants wcreuxd tocalculate percen tage lodging and percentage soft stalks, rcspcctivcly. Plants wcrc uprooted and scored for percentage root infection on a 1-5 rating scale (1 = no infection, 2 = c 10 %, 3 = 1 1  to25%,4=26to50%and5=>50% roots infected). Plant senescence was measured on 1-5 rating xa lc  (1 = foliage completely green, 2 = < lo%, 3 = 11 to 25 %, 4 = 26 to 50 %and 5 =50 % foliage brown and dry). Data were analyzed statistically and correlations werecompu ted among different disease parameters to idcntify the most suitable parameters for estimating charcoal rot severity. Results and Discussion As there was positive corrcla tion between lodging and other discase parameters (Table1 1, percentage lodging was used to dixuss the rcsults. Sowing Dates : Significant differences (P <0.05) were recorded in charcoal rot incidcnce in different cultivars sown on different datcs. Maximum lodging dcveloped in the first sowing at all the locationsin both thexasons(Tables2and 3). Thcrea fter, a gradual dccrcasc was observed in charcoal rot incidcnce in all the tcst cultivars, irrespective of locations and scasons. The difference in the disease incidence emphasized the importance of sowing time with respect to environmental factors prevailing at a particular tcst location. Maximumcharcoal rot dcvelopcd incul tivars sown by mid-September at Patancheru and Dharwad. Anahosur and Patil (1981) reported that CSH 8R sown during Scptcmbcr had the highest incidence of charcoal rot at Dharwad and our results confirm their observation. However, >90 % CSH 6 plants devclopd charcoal rot in the early sowing (4 September 1981) at Madhira and Nandyal(12 Octobcr 1981) which was latcr than the normal postrainy-season sowing. Table 2. Percentage lodging in two sorghum cultivars at three densities sown on different dates at four locations postrainy season sowing (1981-01) Cultivar, plant destiny and % lodging Swing E36-1 CSH 6 O a n d  b t i c m s  date Dl D2 0 3  Mean Dl D2 M Mean mean Dlurwad Pa tanchcru 14 Oa  5.0 5.9 7.4 6.1 33.3 n .9  83.5 44.9 35.5 U O a  0.8 2.5 3.4 22  52.5 5Q4 689 573 29.8 7 N w  0.0 0.8 0.9 0.6 49.2 51.3 54.3 51.6 26.1 16 Nov 2.5 2.5 3.8 2 9 29.6 51.3 521 44.3 23.6 Mean 2.1 3.0 3.9 3.0 41.2 57.7 64.7 54.5 28.7 - ¶ 15- 3.6 4.0 5.6 4.4 100.0 1 00.0 100.0 100.0 522 25 % 2.7 4.4 5.6 4.2 89.8 97.6 !Xi1 94.5 49.4 Et (D 5 0 a  3.4 4 2  4.8 4.2 83.4 83.2 84.9 83.8 44.0 a 015- 4.9 5.8 6.4 5.7 75.0 864 88.4 83.3 44.5 (D 25 Oa 0.9 2.4 3.6 2.4 74.1 85.7 83.6 81.1 41.8 B Mean 3.1 4 2  52 4.2 84.5 9(16 90.6 88.5 46.4 N ~ d y a l  12 oct 1 3 4.7 4.2 3.5 99.2 100.0 99.2 99.4 51.5 24 oct 3 3  3.0 4 3  3.6 66.7 821 92.7 80.5 42.0 t !?2 4 N w  0.5 1 .O 3.9 1.8 643 76.7 82.5 74.5 383 Mean 1.8 2.9 4.1 3.0 76.7 86.3 915 81.8 43.9 2 5 Mdhira : 9 z  0 3  0 3  0.7 0.4 98.3 98.3 100.0 98.9 49.7 0.0 0.0 1 3  0.4 45.0 55.8 625 51.4 27.4 IS Mean 0.2 0 2  1 .O 0.4 71.7 77.7 813 7&7 38.6 "dS Grand mean 1.8 2.6 3.6 2.6 68.5 78.1 820 76.1 39;4 5 Pa tanchru SE(m) fa density (D) f 236"' SE(m) fa cultivar (0 f 1.93." SE (m) for =win dates (SD) f 2.7l0" SE(m)for D XC x5D f 6.68.' Dharwad Nandyal Madhira f0.66 a- f 2.89S9"' f 1.92 f O H * *  f 236"' f 1.57'* a Dl = 66,675 plants ha-1 D3 = 266,700 plants ha-1. D2 = 133.350 plants ha-1, Significant at PC 0.05, and *' at P c 0.001, NS = not significant. Incidence of c h i l d  rot in sorghum 167 Our studies confirm earlier reports (Edmunds, 1964; Odvody and Dunkle 1979) that drought stress and high soil temperatures at grain filling are important factors that predispose sorghum to charcoal rot infection and development. Rainsceased in all locations before flowering (Figs. 1 and 2). Consequently, grain filling took place under continuing moisture deficit stress as indicated by severe charcoal rot incidence in CSH 6. Percentage lodging in SPV 422, SPV 424, and Annegeri-1 were negligible in the crop sown on 4 October 1982 at Patanchem (Table 31, and panicle exertion and subsequent absent. These observations support the earlier findingsof Edmunds and Voigt (1966) that inaddition todrought stress and high temperature, normal seed production is essential to charcoal rot infection. Poor grain filling in these lines was attributed to their non adaptability to the late-sown environment. Plant Population Densities : In 1981-82 season, overall significant differences (P c0.05) were recorded incharcoal rot incidence in the threeplantdensiHesatall testlocations. Highest percentageof lodged plantsoccurred at a plant density of 266, 700 plants ha-1 (Table 2). Loca tion-speci fic differences in pertentage lodging wereobserved for certain sowing dates at Dharwad, Madhira and Nandyal where the disease incidence was at similar for all the three plant densities of CSH 6. Similar observations were recorded in the first and second sowings at Dharwad and in the first sowing at Nandyal. Percentage lodging was significantly lower (P <0.05) in E 36-1 than in CSH 6 at all locations. In the 1982-83 season, severe charcoal rot developed in all cultivars (except E36-1)sown up tomid-Septemberat two locations (Table 3). Thus, even a plant density of 133, 350 plants ha-1 (D2) was sufficient to identify charcoal rot resistance ina rangeofcultivarsin thepostrainyseason in India. These observations confirm the reports of Wadsworth and Sieglinger (1950), and PaHl et al. (1982). It appears that high plant densities increased the inter-plant competition for the available soil moisture that varied over locations, depending upon the soil type. Vertisols of Dharwad and Madhira are shallower and more gravelly than those of Nandyal. I t  is possible that the depletion of moisture in these soils was greater and faster than in the deep Vertisols of Nandyal, whichhavea higherclay content and better water-holdingcapacity. Hsi (1956) and Edmunds et al. (1964) reported high charcoal rot development in sorghum in lighter, sandy soils with low wa ter-holding capacity. Cultivars : Lodging started earlier in CSH 6 than in other cultivars, i.e., 15-30 days after flowering, when i t  was in the milk to soft- dough stage, irrespective of plant densities, sowing da tcs, locations, and seasons (Figs. 1 and 2). Lodging began at the harddough stageinothercultivars, with theexceptionof E 36-1 where it started at grain maturity. In bothseasons significant differences(pc0.05) were observed in charcoal rot incidence (lodging) among the test cultivars. Charcoal rot incidence in E 36-1 was < 10% in comparison to 100% lodged plants in CSH 6 (Tables2 and 3). In the 1982-83 seasonoverall lodging ranged from 3 to 80% in M 35-1, Annegeri-1, SPV 422, and SPV 424. E 36-1 was resistant to lodging and charcoal rot due to its nonsenescence trait. Duncan (1984) and Rosenow (1984) utilized this nonsenesccnce trait in selection for charcoal rot resistance. The posi tive correla tion (Table 1) bctwecn lodging and nonsenescence supports their findings, and suggests that , t t o -  . ..- ...-..... -+. , ...___...-I.-..-1.'  1 4  1 2 3 4  I 2 1 4  l l l l l 2 3 4 l  1 3 1 I 1 1  b )... Hr ow YI I.b Figure 1. Weekly rainfall and tcmpenturrfrom sowing toharvat at Pa*, D h m d  Nandyr1,and M W  in the p b a i n y  season (198142). Dates of f lowing and onset d lodging are given fa rorghum cdtlvar d Incidence of charcoal rot in sorghum + Dotr of mdq P Datr of fbwring A Dotr of initbtion of lodging -+ Dotr of horust - Moalmwm tamp [Y) --- Minimum temp (*C) 1 Roinfoil (mm)  b  SIP^ O C ~  NOV DIG Jon hb Mar - 60- E 5 so- - 5 40- .- 30- 20- Aug S& Oct No* Ow Jon Frb Figure 2. Weekly rainfall and temperature from rowing to harvest at Patanchew and Dharwad In the postralny waron (1982-&3). Datcr, of flowering and onwt of lodging are.glven for sorghum cullivat a t - 1 6 .  170 Pande et al. drought stress enhanced plant senescence and wasdirectlycorrelated withcharcoalrot incidence. , Sowing Dates, Cultivars, and Plant Densities : The effect of interaction among these three factors on charcoal rot incidence in different cultivars was significant (P > 0.05) in the1981-82 seasonat Patancheru and Dharwad, but not at Nandyal and Madhira (Table 2 and 3). Effect of cultivars x sowing dates in disease incidence was highly significant (P < 0.05) at Patancheru and Dharwad during the 1982-83 season. These results indicate that effective field screening under natural infection conditions to identify charcoal rot resistance in grain sorghum is possible in postrainy season sowings in India, and possibly else where i f  environmental conditions are similar. However, the selection of a sowing date for charcoal rot resistance screening would depend on the rainfall pattern, soil type and water-holding capacity, and location. REFERENCES Anahorur, K.H. and Patil S.H. 1981. Dateof planting and inadencc of charcoal rot of sorghum. Sorghum Ncwslelter 24: 1 18-1 19. Dunan.R.R,1984. 'Ihcwocirtiondplmt ~nacmcr with mt and rtdk diseases in sorghum. P a p s  P9- 110 In : Sorghum R d  and Stalk Roh, A Critial M e w ( e d  L K. Mughogho and C Roamberg), ICREAT, Pabnrheru, A.P. 502 324, In&& Edmunds, L K. 1964. Combined relation of plant maturity, temperrture,and soU molrhue tocharcoal stalk rot development In grrln sorghum. Phyfoplhobgy 51 : 514517. Edmunds, L K, Voigt, R. L, and Carasso, F.M. 1964. Use d Ariwnr climate to induce charcoal rot In grain sorghum. Plant M r a s e  Reporter48 : 3003M. Edmunds, L K. and Voigl. R. L 1966. Role d seed production In prcdlspdtionof sorghum t o c h a m 1  rot. Phytoprlhdogy 56 : 876. HSI, C. H, 1956. Stalk rots d sorghum In eastern New Mexico. Plant D ~ x  Reporter 40 : 369-371. ODvody,C. N.and Dunklc, 1. D. 1979. Charcoal stalk rot of sorghum : cffcct of cnvironmcnt on host - parasite relations. Phyloplfhology 69 : 250.254. Patil, R. C., Dohamrnc, N. B, and Pandhrrc, T. M. 1982. Effect of plant density and row spadng on charcoal rot lnddcncein four cultivan of sorghum. Sorghum N w s l c l u r  25 : 110. Rounow, D. T. 1984. Brecding for rcsistmcc to root and stalk rot in Texas. Page  209-218 In Sorghum Root and Stalk Rots, A Critical Rcvlew(ed L K. Mughogho, and G. Roscnberg), ICRISAT, Patanchcnr, A.P. 502 324, Indla. Wadsworth, D. F. and Sicglingcr, J. 8.1950. Qlucoal rot of sorghum. Oklahoma Agricultural Experiment Station tlullctin No. B - 355 pp. Received : 25.1 1.90 Revised : 11.5.92 

Incidence of charcoal rot in sorghum cultivars as affected by sowing date and plant density

http://oar.icrisat.org/3113/1/JA_1344.pdf

Incidence of charcoal rot in sorghum cultivars as affected by sowing date and plant density

Abstract

Similar works

Full text

Available Versions

ICRISAT Open Access Repository