Synergistic effects of some plant growth regulators on in vitro shoot proliferation of korarima (Aframomum corrorima (Braun) Jansen)

The synergistic effects of some plant growth regulators was investigated upon shoot proliferation and growth of korarima (Aframomum corrorima (Braun) Jansen), an important culinary and medicinal plant species native to Ethiopia. Cultures were initiated from axillary bud explants of rhizome using Murashige and Skoog (1962) (MS) medium added with 5% coconut water (CW). The use of 0.5 mg/l thidiazuron (TDZ) in combination with 3 mg/l paclobutrazol (PBZ) gave about 26 shoots/explant (about 12.6-fold than the control) within eight weeks time. Shoot multiplication was also enhanced when TDZ at 0.5 mg/l was simultaneously used with either 2 mg/l imazalil (IMA) or 3 mg/l N6-benzyladenine (BA) in the culture medium. Subsequent shoot elongation and development of functional roots was attained after one to three monthly-subcultures on a plant growth regulator (PGR)-free basal medium. The protocol developed from the present study could be used for the large-scale multiplication of A. corrorima by tissue culture

Managing acid soils for reclaiming livelihoods in Ethiopia

Soil acidification is the result of a complex set of processes caused both naturally and by human activity. It limits plant growth because of conditions that increase base element deficiencies, Phosphorus-fixation and toxicities of Aluminum, Manganese and Hydrogen ions

Resistance of maize varieties to the maize weevil Sitophilus zeamais (Motsch.) (Coleoptera: Curculionidae)

This study aimed at evaluating commonly used maize varieties, collected from Melkasa and Bako Agricultural Research Centers and Haramaya University, Ethiopia, against the maize weevil Sitophilus zeamais Motsch., one of the most important cosmopolitan stored product pests in maize. A total of 13 improved maize varieties were screened for their relative susceptibility to S. zeamais. The Dobie index of susceptibility was used to group the varieties. The variety, ‘BHQP-542’, had the least index ofsusceptibility and was regarded as resistant. The varieties, ‘Katumani’, ‘Melkasa-I’, ‘Melkasa-II’, ‘Melkasa-III’, ‘Coree’, ‘BH-541’, ‘BH-660’, ‘BH-540’, ‘Rare-I’, ‘Awasa-511’, ‘ACV3’ and ‘ACV6’, were moderately resistant. Weevils fed with the resistant variety produced low numbers of F1 progeny, had a high median developmental time and a low percentage of seed damage and seed weight loss. Maize varieties with a high F1 progeny tended to have a short median developmental time. An increasingnumber of F1 progeny resulted in an increasing seed damage and seed weight loss. We found an inverse relationship between the susceptibility index and percent mortality and median developmental time; however, the numbers of F1 progeny, percent seed damage and seed weight loss were positively related with the susceptibility index. The use of resistant varieties should be promoted in managing S.zeamais in stored maize under subsistence farming conditions in Africa

Determinants of Artificial Insemination Use by Smallholder Dairy Farmers in Lemu-Bilbilo District, Ethiopia

Despite Ethiopia possessing the highest number of livestock in Africa, its benefit to the country and smallholder farmers is small as more than 99% of the cattle are indigenous breeds with low yield. Though the government introduced Artificial Insemination (AI) technology to improve this condition, the adoption rate by smallholder farmers is still low. The objectives of the study were to determine factors affecting adoption and the extent of adoption of among smallholder dairy farmers in Lemu-Bilbilo district of Ethiopia. Data from 196 smallholder dairy farmers was collected using semi-structured questionnaire. The study utilized double-hurdle model for analysis where the two stages were run separately as Probit and truncated regression, respectively. Contacts with extension agents, access to credit, income from milk sales, feeding concentrate to cows and family size influenced the probability of adoption without affecting the extent of adoption. While membership in dairy cooperatives and off-farm income positively affected the probability and extent of AI adoption, distance from AI station and access to crossbred bull services influenced both variables negatively. Education level and efficiency of AI service had positive impact on the extent of AI use; whereas experience in keeping cross-breeds and years of using AI had negative influence on same. Much work should be done to improve the accessibility of AI service by expanding AI stations throughout the district, by training more AI technicians and by encouraging private involvement. Adult education and education in farmers training centres can be the way forward to improve educational status of farmers. Bureau of Agriculture must work to improve access to credit and extension services; established dairy cooperatives have to be strengthened and more need to be established. Keywords: adoption, artificial insemination, double hurdle mode

First report of soybean witchesbroom disease caused by Group 16SrII phytoplasma in soybean in Malawi and Mozambique

Soybean (Glycine max L.) is an important grain legume cultivated on approximately 1.24 million ha in Africa (1). Malawi ranks fourth in area of production in Africa, with 75,000 ha in 2009 (1). Soybean is also gaining importance in Mozambique and several other southern African countries due to diversification programs. During a field survey conducted in March 2010, soybean plants with phyllody and witches'-broom disorders typical of phytoplasma infection were observed in three of five fields surveyed in Lilongwe (Chitedze Research Station) and Salima (Channa, Chitala) districts in Malawi and three of four fields surveyed in Zambezia Province in Mozambique. Symptoms consisted of shoot proliferation, reduced leaflets, shortened internodes, proliferated auxiliary shoots producing witches'-brooms, virescence, and phyllody. Incidence of symptomatic plants was <1% in Malawi and 10 to 15% in Mozambique. Yield loss was 100% in affected plants. Five leaf samples each from symptomatic and asymptomatic plants were collected from six fields; total genomic DNAs were isolated and used as templates in PCR using phytoplasma-universal primer pair P1 and P7 for 16S-23S ribosomal RNA encoding region (3). PCR amplicons (1,709 bp) were produced from only templates derived from symptomatic plants. Amplicons from a symptomatic plant each from Malawi (Channa, Salima District) and Mozambique (Mutequelse, Zambezia Province) were directly sequenced in both directions and submitted to the GenBank (Accession Nos. HQ840717 and HQ845208). Nucleotide sequences of the two African soybean witches'-broom (SoyWB) phytoplasma strains were 100% identical. The virtual restriction fragment length polymorphism (RFLP) pattern derived from these sequences using iPhyClassifier software (4) was similar to the reference pattern of the 16Sr group II, subgroup C (cactus phytoplasma, Accession No. AJ293216), with a pattern similarity coefficient of 0.99. A BLASTn search revealed that the African SoyWB phytoplasma sequences had a nucleotide sequence identity of 99% with those of soybean phytoplasma from Thailand (Accession No. EF193353), cactus phytoplasma from China (Accession No. EU099561), and several other members of 16SrII group. Phylogenetic analysis revealed the clustering of these strains with members of 16SrII group. In 1984, the occurrence of phyllody and witches'-broom symptoms in soybean in Mozambique was reported (2), however, no comprehensive details on the pathogen are available. To our knowledge, this is the first report of phyllody and witches'-broom disease in soybean in Malawi and the first molecular evidence of association of a 16SrII-C group ‘Candidatus phytoplasma’ with the disease in Malawi and Mozambique. Phyllody and witches'-broom is a destructive disease, and its widespread occurrence can adversely affect soybean production in sub-Saharan Africa. Identification of alternative hosts and vector species would improve our understanding of the disease's epidemiology and contribute to development of appropriate tactics to prevent escalation of this problem into a major disease

Grain yield, stem borer and disease resistance of new maize hybrids in Kenya

Evaluation of 30 maize hybrids for yield and resistance to stem borers and foliar diseases in four agroecologies in Kenya was conducted in 2009. There were significant differences among the hybrids in leaf damage, number of exit holes, tunnel length and grain yield in Kiboko. The maize hybrids CKPH08014, CKPH08025, and CKPH08026 showed the least leaf damage, exit holes and tunnel length, similar to the resistant check. Although ten hybrids yielded over 8 t/ha, two hybrids, CKPH09001 and CKPH08033, gave the highest yield of 8.99 and 8.86 t/ha, respectively, in Kiboko. There were significant differences among the hybrids in resistance to leaf rust and maize streak virus in Kakamega. The intensity of foliar diseases was high in Kakamega compared to the other sites. All hybrids appeared resistant to the foliar diseases at Kakamega. On the average, the highest yield of the hybrids was recorded in Kiboko (7.5 t/ha) followed by Kakamega (6.1 t/ha), and the least at Embu (3.5 t/ha), and Mtwapa (3.14 t/ha). The performance of the hybrids varied from site to site, with CKPH09002 and CKPH09003 performing well at Mtwapa, CKPH09001 at Kiboko, CKPH08039 at Embu, CKPH 08002 and CKPH08010 at Kakamega.Key words: Host plant resistance, maize, pest management, stem borer, foliar disease

Seed quality and mycoflora associated with chickpea (Cicer arientinum L.) seed in Ethiopia

The study was conducted at Ethiopian Institute of Agricultural Research, Haramaya University and Jimma University, Ethiopia. Crop yield is directly associated with the physical and biological quality of planting material or seed. Ninety-nine (99) chickpea seed lot samples were collected for physical purity, seed health and germination tests from major chickpea growing areas in Ethiopia in the 2016/17 cropping season to assess the status of chickpea seed health and quality among subsistence farmers, research stations and seed growers. The seed lots were grouped as researcher saved, farmers saved and seed growers’ saved seed. The maximum physical purity of 97.5% was recorded for the researcher saved seed lots, 90.8% for the seed growers and 87.4 % for the farmers saved seeds. Foreign matters and broken seeds were the most contaminants found in the seed lots. The seed germination percentages were in the range of 96.3% to 98.5% for all seed sources and there were no significant differences among the seed lot samples. A total of seventeen (17) fungi species were isolated from all seed sources with different frequency and amount. These are Fusarium spp., Aspergillus sp., A. niger, A. flavus, A. nidulans, A. candidus, A. fumigatus, Penicillium sp., Rhizopus sp., Verticillium sp., Rhizoctonia sp., Pythium sp., Alternaria sp., Helminthosporium sp. Phylostica sp., Cladosporium sp., Negrospora sp. Aspergillus flavus was found the most dominant&nbsp; with recovery (Relative Density=21.53%, Infection rate=10.36%, and Infection Frequency=25.59 %) from all seed lots. There were high variations in relative density, Infection rate, and Infection frequency among isolated fungi. Ascochyta rabiei the most important&nbsp; chickpea disease was not found in this study. This might relate to the incidence and prevalence of sample collection season/cropping year which was low in expected areas. The current study concluded that there are seed qualities and seed health management issues with regards to different seed sources (farmers, research and private sectors); this entails strong seed quality control and growers’ awareness creation on storage sanitation, seed health test before sowing, and production of healthy crops. To keep the seed health in a better condition, seed growers should keep a wider interval of rotation, develop use of the healthy improved seed, after some&nbsp; generation (4-5), seed grading to avoid loss of physical purity, use of appropriate storage container (ventilated and clean), seed dressing with safe pesticides, and appropriate moisture level for storage (about 14%) should have to keep. Longer storage also gives a chance to contaminate the whole seed and can expose to decay. Key words: Chickpea, fungi, germination, mycoflora, purity, seed health, seed source