Septoria and Stagonospora Diseases of Cereals - CIMMYT ...

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Septoria tritici Resistance of Wheat Cultivars at Different Growth Stages M. Díaz de Ackermann, 1 M.M. Kohli, 2 and V. Ibañez1 1 INIA La Estanzuela, Colonia, Uruguay 2 CIMMYT Regional Wheat Program, Uruguay Abstract Nine wheat cultivars planted in the greenhouse were inoculated with a mixture of three isolates of Septoria tritici at four different growth stages. The first evaluation, done six weeks after inoculation, showed that the facultative wheats at growth stage (GS) 39 (flag leaf ligule just visible) and spring wheats at GS 65 (flowering halfway complete) reached the highest levels of infection, with two exceptions, cvs E. Pelón 90 and P. Oasis. In the second evaluation a week later, the highest level of infection was reached when facultative wheats were inoculated at GS 32-33 (stem elongation-first node detectable) and spring wheats at GS 39 (flag leaf ligule just visible). In both evaluations, the effects of cultivars, seeding date/GS at inoculation, and the interaction between cultivars and GS at inoculation were significant. Septoria tritici susceptibility increased with the age of the plants. The increase in the level of infection was significantly lower in cv P. Superior (Bobwhite), indicating a certain level of adult plant resistance. Wheat is an important crop in the western region of Uruguay, where it is grown for grain and forage (double purpose) in the mixed farming system, or solely for grain production. Among diseases present in the country, Septoria tritici leaf blotch is one of the most important, and it can be particularly severe during the wheat-growing season in this temperate high rainfall environment. The wide range of planting dates from May (or even earlier for double purpose crops) to August determines the growth stage (GS) at the time of primary infection, later in the fall or in early spring. Facultative wheats, sown in the fall, are infected very early (seedling stage) or at the beginning of spring (boot stage), depending on the year. Spring wheats, sown later than the facultative types, are exposed mainly to spring infections. Reduced disease severity associated with tall plant stature and late maturity has been observed (Danon et al., 1982; Eyal and Talpaz, 1990; van Beuningen and Kohli, 1990; Tavella, 1978). However, the relationship between the resistance expressed at the seedling stage and the adult plant stage, or vice versa, is not fully understood. Kema and van Silfhout (1995) found significant correlations for one of three isolates inoculated on 22 wheat cultivars at the seedling and adult plant stages. On the other hand, Arama, Parlevliet, and van Silfhout (1994) described three types of resistance: resistance only in seedling (seedling resistance), resistance only in adult plant (adult plant resistance), and resistance in both seedling and adult plant (overall resistance). The objective of this study was to determine the level of resistance in nine wheat cultivars, representing different reactions to S. tritici in the field, at different growth stages and under controlled conditions. Materials and Methods 131 Nine wheat cultivars with different growth habits and field reactions to Septoria tritici were planted in three pots each, five plants per pot, on four seeding dates: 28 April . , 16 May . , 31 May . , and 27 June 1995. The pots measured 29 and 20 cm in their upper and lower diameters, respectively, and 20 cm in height. The cultivars’ growth habit, progenitors, and field reaction to S. tritici are presented in Table 1. The concentration of S. tritici spore suspension was adjusted to 106 conidia per ml, with the aid of a hemacytometer. The cultivars were inoculated with a mixture of three isolates (26S, 4407, and E. Federal) on 17 July, at the growth stages (Zadoks et al., 1974) indicated in Table 2. The selected isolates were characterized by Diaz de Ackermann et al. (1994). The plants were kept in a humid chamber until 20 July. Due to the delayed
Session 6C — M. Díaz de Ackermann, M.M. Kohli, and V. Ibañez 132 appearance of symptoms, two evaluations were done, the first on 28 August . and the second on 5 September. The infection was scored as percent of leaf area affected by the disease, on two tillers per plant and five leaves per tiller. Transformed data (Loge +0.5) for the flag leaf, F-1, and F-2, as well as the average of the three leaves, were analyzed using SAS GLM procedure (Version 6.12; SAS Institute, Cary, NC). Infection on the lower two leaves was not included in this analysis due to many missing values. Results and Discussion The analysis of variance (ANOVA) for each leaf and the average of the three leaves showed significant differences between cultivars and seeding dates, as well as significant interaction between seeding dates and cultivars in both evaluations. As the results were similar for individual leaves and the average of the three top leaves, only data for the latter are presented (Table 3). Differences among cultivars were found on the first two seeding dates (28/04 and 16/05) during the first evaluation, and on the intermediate dates (16/05 and 31/ 05) during the second evaluation. All the cultivars except B. Charrúa showed different infection levels on different seeding dates at first evaluation. This interaction is explained by the cultivars’ different Table 1. Cross, growth habit and field reaction to Septoria tritici of nine wheat cultivars. Cultivar Cross Growth habit Reaction E. Cardenal Veery#3 Spring S1 INIA Mirlo Car 853/Coc//Vee#5/3/Ures Spring R E Pelón 90 Kavkaz/Torim73 Spring R-MR ProINTA Superior Bobwhite Spring MR ProINTA Oasis Oasis/Torim Spring S E. Federal E.Hornero/CNT8 Facultative MR E Halcón Buck6/MR74507 Facultative MR Buck Charrúa RAP/RE//IRAP/3/LOV/4/RAP/RE//IRAP Facultative R LE 2196 E. Jilguero/ND526 Facultative R 1 S: susceptible, R: resistant, MR: moderately resistant. Table 2. Growth stages of spring and facultative wheat varieties at time of inoculation. Seeding date 28/04 16/05 31/05 27/06 Spring wheats 65 39 30-31 22-23 Facultative wheats 39 32-33 30 24-25 Table 3. Average level of infection of top three leaves, comparison among date of seeding (small letter) and cultivars (capital letter). Evaluation August 28th and September 5th . Sowing date 28/04 16/05 31/05 27/06 GS Facultative 39 32/33 30 24/25 GS Spring 65 39 30/31 22/23 Cultivar 1st . eval 1st . eval 2nd . eval 1st . eval 2nd . eval 1st . eval 2nd . eval E.Cardenal 11.65 aA 3.81 bA 46.24 aA 0.16 c 3.57 bA 0.00 c 0.45 c I. Mirlo 1.98 aCD 2.17 aAB 23.93 aB 0.00 b 1.96 bB 0.00 b 0.66 c E. Pelón 90 1.32 aDE 2.20 aAB 16.86 aC 0.02 b 1.76 bB 0.00 b 0.19 c P. Superior 2.92 aC 1.50 bB 8.14 aD 0.00 c 1.86 bB 0.00 c 0.11 c P. Oasis 1.79 bCD 4.25 aA 27.22 aB 0.26 c 2.18 bB 0.02 c 0.44 c E. Federal 7.64 aB 3.17 bA 19.15 aC 0.00 c 0.50 bD 0.00 c 0.43 b E. Halcón 1.25 aE 0.23 bC 3.61 aE 0.03 b 1.13 bC 0.00 b 0.17 c B. Charrúa 0.14 aE 0.03 aC 2.91 aE 0.00 a 0.56 bCD 0.00 a 0.44 b LE 2196 1.66 aDE 0.22 bC 6.65 aD 0.03 b 1.23 bB 0.00 b 0.33 c Average 3.37 1.95 17.19 0.06 1.64 0.00 0.36 behavior on the different seeding dates/GS at inoculation. Early seedling infection demonstrated higher sensitivity for detecting differences among cultivars. During this evaluation, the facultative wheat varieties were found to have higher Septoria susceptibility at GS 39 (flag leaf ligule just visible) and spring varieties at GS 65 (flowering halfway complete). These were followed by GS 32/33 (stem elongation-first node detectable) and GS 39 for facultative and spring varieties, respectively. Inoculations at GS 22 to GS 31 did not produce adequate infection levels. At the second evaluation on 5 September, the group seeded on the first date was already dry. For the remaining three sowing dates, the highest infection level was shown by facultative wheat varieties inoculated at GS 32-33 and by spring wheat varieties inoculated at GS 39. Comparison of the cultivars’ field reactions to S. tritici with infection under controlled conditions showed differences in I. Mirlo, P. Superior, E. Halcón, and P. Oasis. These cultivars are considered resistant (R), moderately resistant (MR), moderately resistant (MR), and susceptible (S), respectively, under field conditions; under controlled conditions they were
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Septoria and Stagonospora Diseases
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ii The Organizing Committee express
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iv 87 Genetic Variability in a Coll
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vi Foreword In the mid-1970s the id
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2 Opening Remarks — S. Rajaram ar
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4 Opening Remarks — S. Rajaram Ta
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6 Opening Remarks — S. Rajaram cu
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8 Opening Remarks — S. Rajaram br
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10 Opening Remarks — S. Rajaram T
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12 Opening Remarks — S. Rajaram t
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14 Opening Remarks — S. Rajaram C
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16 Opening Remarks — S. Rajaram r
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Session 1: Pathogen Biology Biology
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Table 2. The Septoria tritici/Stago
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Molecular Analysis of a DNA Fingerp
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histidine kinase in yeast, although
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According to the previous observati
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cultivars. The presence of pycnidia
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Provided that S. nodorum fungal gen
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;; yy ;; yy 6 28% 1 32% ;y; ; y y ;
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Table 1. Sources of isolates or DNA
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Septoria/Stagonospora Leaf Spot Dis
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Interrelations among Septoria triti
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42 Session 2 — B.M. Cunfer disper
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44 Session 2 — B.M. Cunfer beyond
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46 Aggressiveness of Phaeosphaeria
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48 Session 2 — P. Halama, F. Lala
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50 Growth of Stagonospora nodorum L
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52 Session 3A — G.H.J. Kema and E
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54 A Possible Gene-for-Gene Relatio
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56 Diallel Analysis of Septoria Tri
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58 Session 3A — X. Zhang, S.D. Ha
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60 Session 3A — L. Gilchrist, C.
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62 Session 3A — L. Gilchrist, C.
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64 Session 3B — E. Arseniuk and P
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68 Cultivar variances Cultivar vari
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72 Session 3B — N.E.A. Murphy, R.
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74 Inheritance of Septoria Nodorum
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76 Session 3B — N.E.A. Murphy, R.
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78 Session 4 — B.A. McDonald, C.C
Page 87 and 88: 80 Session 4 — B.A. McDonald, C.C
Page 89 and 90: 82 Session 4 — B.A. McDonald, C.C
Page 91 and 92: 84 Session 4 — E. Arseniuk, H.S.
Page 93 and 94: 86 Session 4 — C. Cowger, C.C. Mu
Page 95 and 96: 88 each isolate. Two of the probes
Page 97 and 98: 90 Mating Type-Specific PCR Primers
Page 99 and 100: 92 Session 4 — Bennett, R.S., S.-
Page 101 and 102: 94 Session 5 — M.W. Shaw and the
Page 103 and 104: 96 Session 5 — M.W. Shaw The path
Page 105 and 106: 98 Spore Dispersal of Leaf Blotch P
Page 107 and 108: Session 5 — C.A. Cordo, M.R. Sim
Page 109 and 110: 102 Epidemiology of Seedborne Stago
Page 111 and 112: Session 5 — D.A. Shah and G.C. Be
Page 113 and 114: 106 Session 6A / Session 6B — J.M
Page 119 and 120: Session 6A / Session 6B — C.C. Mu
Page 125 and 126: 118 Session 6C — M. van Ginkel an
Page 135 and 136: Session 6C — G. Shaner 128 An exa
Page 137: Session 6C — G. Shaner 130 Anothe
Page 141 and 142: 134 Septoria tritici Resistance Sou
Page 143 and 144: Session 6C — L. Gilchrist et al.
Page 145 and 146: Session 6C — L. Gilchrist et al.
Page 147 and 148: 140 Selecting Wheat for Resistance
Page 149 and 150: Session 6C — R.M. Gonzalez I., S.
Page 151 and 152: Session 6C — R.M. Gonzalez I., S.
Page 153 and 154: Session 6C — R. Loughman, R.E. Wi
Page 155 and 156: 148 Field Resistance of Wheat to Se
Page 157 and 158: 150 Using Precise Genetic Stocks to
Page 159 and 160: Session 6C — C.M. Ellerbrook, V.
Page 161 and 162: 154 Evaluating Triticum durum x Tri
Page 163 and 164: 156 Sources of Resistance to Septor
Page 165 and 166: Session 6C — H. Toubia-Rahme and
Page 167 and 168: 160 Partial Resistance to Stagonosp
Page 169 and 170: Session 6C — C.G. Du, L.R. Nelson
Page 171 and 172: Session 6C — D.E. Fraser, J.P. Mu
Page 173 and 174: Session 6C — C.G. Du, L.R. Nelson
Page 175 and 176: Session 6C — M. Mincu 168 Arcsin
Page 177 and 178: 170 Comparison of Greenhouse and Fi
Page 179 and 180: Session 6C — S.L. Walker, S. Leat
Page 181 and 182: Session 6D — L.N. Jørgensen, K.E
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Page 185 and 186: Concluding Remarks — Z. Eyal 178
Page 187 and 188: Concluding Remarks — Z. Eyal 180
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Concluding Remarks — Z. Eyal 182
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184 Dr. Patrice Halama Professor In
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186 Dr. Hala Toubia-Rahme Research
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