Responses of compact coffee (coffea arabica) clones to coffee berry disease and leaf rust under varied environmental condmons in Tanzania.
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Date
2013
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Publisher
Sokoine University of Agriculture
Abstract
Sixteen (16) compact coffee genotypes (Coffea arabica L.) were tested fbr their response
to coffee berry disease (CBD) and coffee leaf rust disease (CLRD), to determine yield
potential, and the effects of soils and climatic conditions on bean grades and beverage
quality. Commercial Arabica coffee hybrids N39-6 and KP423-2, N39 and PNI088 were
included as standard checks. CBD and CLRD tests under varied environmental and
controlled conditions showed significant level of variability (P>0.05) of the coffee
genotypes. Compact coffee genotype CVT14 showed resistance under natural and
controlled conditions. In this study, compacts were shown to have yield potentials as high
as 7000 Kg/ha. N39 produced the lowest yields ranged 470 to 1493 Kg/ha. Correlation
(r values of 0.104, -0.14 and -0.15; 0.44 at 0.05 and 0.56 at 0.01; n-2 df n=20) and
regression (tb values of 0.40, -0.53 and -1.95; 2.1 at 0.05 and 2.8 at 0.01; n-2 d.f, n=20)
analysis indicated non consistency on yield performance of the genotypes across
locations. Significant yield performance (P>0.05) of the compact hybrids were detected
within locations. Correlation of yields of coffee genotypes with CBD and CLRD (r value
for CBD 14.44, CLRD 18 504; 0.482 at 0.05 and 0.606 at 0.01; n-2 d.£ n=17), indicated
strong evidence that yields of coffee clones are affected by the two diseases. Non
significant variations were found on bean grades and mineral composition of the compact
coffee genotypes (P<0.05; 0.01). CVT10 had the highest proportions of AAs (41-43%)
and CVT5 the lowest (4-6%). Two genotypes CVT6 (17-34%) and CVT15 (28-29%) had
a higher proportions of pea berries. Pea berries have special coffee market because they
produce pleasant aroma upon roasting. Out of 16 compact coffee genotypes, 15 scored
class 5-6 values for export, and one (1); CVT6 scored class 4 described as specialty
coffee. Rainfall of 1500 mm average per annum, sunshine 4-5, hrs/day and radiation of
110 to 14 kj per day during ripening stage influence positively bean size and cup taste of compact coffee genotypes. Characterization of H. vastatrix revealed seven (7) new races:
XLII, XLI, XXX, XXXIII, XV, XXXIV and XXXIX. Four C. kahawae strains: 2006/14,
2010/2, 2006/7 and 2010/1 were less pathogenic to six compact coffee genotypes; CVT2,
CVT4, CVT5, CVT7, CVT8 and CVT13.
Description
Keywords
Responses of compact coffee, Coffee Arabica, Berry disease, Environmental condmons, Tanzania.