World Journal of
Pharmaceutical and Life Sciences

ASSESSMENT OF ROBUSTA COFFEE GENOTYPES ON THEIR REACTION TO COFFEE WILT DISEASE AND BREEDING FOR RESISTANCE

Nyabisi Maliyatabu Ng’homa*, Paul Mbogo Kusolwa, Delphina Peter Mamiro and Deusdedit Linus Kilambo

ABSTRACT

Coffee wilt is the most destructive disease affecting robusta coffee in Tanzania. Since its outbreak in 1997 the disease has spread throughout the robusta coffee growing districts in Kagera region causing a loss of 1% of robusta coffee produced in Tanzania. A study was conducted to assess the performance of the hybrids of C. canephora against coffee wilt disease (CWD) and to screen germplasm of cultivated and wild coffee from Bushenyi and Minziro forests. A total of 7,320 individual seedlings from 124 genotypes were artificially inoculated with Fusarium xylarioides, a pathogen that causes coffee wilt disease. Resistant genotypes 13/61 and ML2 were crossed to two susceptible commercial varieties MS1 and MS2. The F1 progenies and their parents were inoculated with F. xylarioides pathogen. The results showed that 93% of screened C. canephora seedlings were susceptible, while 7% were resistant to CWD at various levels. About 3.3% of resistant genotypes demonstrated complete resistant to the pathogen. The complete resistant genotypes were wild coffee accessions FB1, FB2, FB3 and FB4 from Bushenyi forest. Significant differences in the response of F1 hybrids to CWD pathogen were observed at P ? 0.001. High survival rates were recorded on the resistant parents (13/61 and ML2), while the lowest survival rates were observed on the susceptible parents (MS1 and MS2). A total of 78 out of 240 tested F1 hybrids did not succumb to CWD. The overall results showed that transfer of resistant genes from the donor to the recipient parents is very low. All cultivated C. canephora which have exhibited resistant or tolerant together with wild genotypes which are completely resistant to CWD should be evaluated for advanced development of coffee varieties.

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