International Journal of Agricultural Sciences ISSN: 2167-0447 Vol. 2 (6), pp.198-203, June, 2012. Available online at www.internationalscholarsjournals.org © International Scholars Journals Full Length Research Paper Variation in resistance to coffee berry disease (colletotrichum kahawae) among germplasm progenitors at Tanzania coffee research institute (tacri) D.J.I. Mtenga1* and S.O.W.M. Reuben2 1Tanzania Coffee Research Institute, P.O. Box 3004, Moshi, Tanzania. 2Sokoine University of Agriculture, Department of Crop Science and Production, P.O. Box 3005, Morogoro, Tanzania. Received February 23, 2012; Accepted June 03, 2012 Four trials were executed at the Tanzania Coffee Research Institute (TaCRI) from September 2006 to April 2007 and at the Coffee Rust Research Center (CIFC), Portugal from March 2007 to June 2007 to evaluate variation in resistance to Coffee Berry Disease (CBD) caused by Colletotrichum kahawae within and among four Coffea arabica varieties. The varieties tested were Bourbon, Compacts (Catimor), Rume sudan and Hybrid de Timor obtained from TaCRI germplasm. Local CBD isolate was used in the trials at TaCRI while at CIFC Portugal, four CBD isolates T3, Ca1, Z9 and Q2 were used in the resistance evaluation. There was significant (P ≤ 0.05) variation against CBD within and among varieties against most isolates. Accessions PNI086, VCE1589 and VC299 in varieties Compacts, Hybrid de Timor and Rume sudan respectively showed high resistance while variety Bourbon a control, showed high levels of susceptibility. It is therefore necessary in breeding programmes to select the best accessions within varieties for development of superior coffee varieties with resistance to CBD. Key words: Coffee berry disease; breeding; Coffea arabica; resistance sources INTRODUCTION Coffee (Coffea) is one of the most important beverages in Coffea arabica L. and Coffea canephora Pierre ex the world with a current estimated value of 10 billion US$ Froehner. In the world coffee trade, Arabica coffee and it is ranked second largest trade commodity next to accounts for about 70% while Robusta coffee contributes petroleum (Luiz et al., 2005). Coffee is also an extremely about 30% (ICO, 2006). Coffee is Tanzania’s largest important source of national export revenue and internal export crop. It contributes approximately $115 million to cash income for farmers in many poor countries from export earning, and provides employment to some Africa, Asia and Latin America (ICO, 2005). The two most 400,000 families. About 95 percent of coffee is grown by economically important species of the genus Coffea are smallholders on average holdings of 1–2 hectares, and 5 percent is grown on estates. Almost all of Tanzania’s coffee production is exported (Baffes, 2003). Numerous production constraints have been mentioned. _____________________________ However, the most serious one is diseases, mainly coffee *Corresponding Author’s E-mail: [email protected] berry disease (CBD) (Colletotrichum kahawae, Waller Mtenga & Reuben 198 Table 1: Varieties and accessions studied Variety Accessions Rume sudan VC 298, VC 299, VC 506, VC509, and VC510 Hybrid de Timor RRC70, RRC72, VCE 1594, VCE 1587and VCE1589 Catimor/Compacts PNI 088, PNI 086, PNI 087, CR 124 and CR127 Bourbon N5, N39, N100, N197 and N218 Note: Bourbon is a commercial (susceptible) variety, used as a check. and Bridge) and coffee leaf rust (CLR) (Hemileia Four Coffee Berry Disease isolates from Tanzania (T3), vastatrix, Berk et Br). Coffee Berry Disease is an Kenya (Q2), Zimbabwe (Z9) and Cameroon (Ca1) were anthracnose of the green and ripening berries while used for the experiments done at CIFC- Portugal while a Coffee Leaf Rust is a fungal disease which attacks leaves local isolate extracted from freshly infected berries was of both Arabica and Canephora coffee (Wrigley, 1988). used for the experiment done in Tanzania. Together, the two diseases viz CBD and CLR control account for 40% of total production cost for small scale Experimental procedure coffee producers in the country (Teri et al., 2004; Mtenga et al., 2006). The Arabica coffee improvement programme at the Tanzania Coffee Research Institute (TaCRI) has Fully matured, red-ripe coffee berries were handpicked achieved a considerable success in developing CBD and from the trees from centre rows of each accession CLR resistant varieties. However some inconsistencies involved from the germplasm plot. These were pulped on the levels of resistance have been observed in some using a small hand pulper in separate lots for each of the progenitors used in the development of the accession. The pulper hopper was washed thoroughly varieties (Walyaro, 2004). Establishment of levels of using clean tap water under high pressure to ensure all resistance in the progenitors of resistance will lead to the cherries from previous lot is cleaned out of the pulper identification of superior which will be used for before pulping the next lot. This procedure was followed development of improved varieties with consistent, stable for all lots. Pulped cherries from each accession were put and durable resistance to the diseases. The objective of in separate containers, placed under room temperature the current study was to evaluate the resistance levels for 72 hours for fermentation. Then the cherries were within and among the main progenitors of CBD washed and dried under shed separately in partitioned resistance used at TaCRI. wire-mesh trays for one week before they were pre- germinated to raise hypocotyls. Sources of inoculums MATERIALS AND METHODS According to Cook (1973b) green infected berries with Varieties and accessions studied active lesions are the best source of inoculum for initial isolation because of low contamination with other non The materials which were used in this work are three pathogenic Colletotrichum spp. and optimum coffee varieties from Tanzania Coffee Research Institute pathogenicity of the isolates. Initial isolation of the CBD germplasm which are the main progenitors for CBD pathogen was achieved by incubating green infected resistance. In each variety, five accessions were berries from unsprayed susceptible variety Bourbon evaluated as shown in Table 1. (N39) at 200C-240C on moist sterilized sand in closed but somewhat ventilated plastic boxes for 10 days (Cook, CBD isolates tested 1973b). This was followed by planting the conidia on 199 Int. J. Agric.Sci. Table 2: Variation in resistance to coffee berry disease (CBD) 0-4 score within varieties against Q2, Ca1, T3, Z9 CBD isolates at CIFC Portugal and Local one in Tanzania Varieties Accessions Isolates Mean Scores Rume sudan Q2 Ca1 T3 Z9 Local VC 298 0.350 2.550 1.000 0.733 0.160 VC 299 0.817 1.133 1.067 0.500 0.040 VC 506 0.683 2.233 0.900 0.983 0.040 VC 509 0.767 3.900 1.217 0.833 0.060 VC 510 0.633 3.650 0.850 0.750 0.060 mean 0.650 2.693 1.007 0.760 0.072 CV (%) 29.620 8.790 32.950 20.650 89.580 SE± 0.000 0.137 0.000 0.091 0.000 LSD0.05 ns 0.446 ns 0.298 ns Hybrid de Timor VCE 1587 0.883 2.583 1.967 1.833 0.010 VCE 1589 0.783 2.400 0.633 0.950 0.050 VCE 1594 3.717 3.883 1.933 2.183 0.340 RRC 70 2.283 3.933 1.417 2.183 0.440 RRC 72 1.300 3.617 2.150 1.600 0.050 mean 1.793 3.283 1.620 1.750 0.178 CV (%) 15.260 6.360 19.500 18.980 70.300 SE± 0.158 0.121 0.183 0.192 0.061 LSD0.05 0.516 0.395 0.595 0.625 0.189 Compacts PNI 086 0.567 1.850 0.950 0.717 0.000 PNI 087 2.033 3.800 1.600 1.783 0.010 PNI 088 0.050 3.85 0.167 0.283 0.000 CR 124 1.350 3.900 2.317 2.367 0.470 CR 127 0.850 3.967 1.817 0.750 0.040 mean 0.970 3.473 1.370 1.180 0.104 CV (%) 23.030 5.590 12.830 20.140 35.630 SE± 0.129 0.113 0.102 0.153 0.158 LSD0.05 0.421 0.367 0.332 0.498 0.487 Bourbon N 5 4.000 4.000 4.000 4.000 3.590 N 39 4.000 4.000 4.000 4.000 3.510 N 100 4.000 4.000 4.000 4.000 1.980 N 197 4.000 4.000 4.000 4.000 1.430 N 218 4.000 4.000 4.000 4.000 3.390 mean 4.000 4.000 4.000 4.000 2.780 CV (%) 0.000 0.000 0.000 0.000 14.620 SE± 0.000 0.000 0.000 0.000 0.211 LSD0.05 ns ns ns ns 0.650 Mtenga & Reuben 200 3.4% malt extract agar containing 0.04% streptomycin. A RESULTS 6 spore suspension containing 2 x10 spores/ml was prepared from these pure cultures. The suspension was There was significant (P≤0.05) variation in resistance to tested and proved spore viability in excess of 80%.This coffee berry disease (CBD) within varieties Hybrid de procedure was followed in extraction and preparation of Timor, Compacts and Bourbon against a local isolate at inoculum of the local CBD isolate used in the experiment TaCRI Tanzania (Table 2). No significant variation was conducted in Tanzania. For the experiments carried out observed between accessions in Rume sudan variety. in Portugal; isolates were maintained in malt extract agar Rume sudan, Hybrid de Timor and Compacts showed (MEA) and preserved for long periods in agar slants. high levels of resistance with mean scores of 0.072, 0.178 and 0.104 respectively.