Vegetatively propagated crop (VPC) seed tends to remain true to varietal type but is bulky, often carries disease, and is slow to produce. So VPC seed needs to be handled differently than that of other crops, e.g., it tends to be sourced locally, often must be fresh, and it is less often sold on the market. Hence, a framework was adapted to describe and support interventions in such seed systems. The framework was used with 13 case studies to understand VPC seed systems for roots, tubers, and bananas, including differing roles and sometimes conflicting goals of stakeholders, and to identify potential coordination breakdowns when actors fail to develop a shared understanding and vision. In this article, we review those case studies. The framework is a critical tool to (a) document VPC seed systems and build evidence; (b) diagnose and treat coordination breakdown and (c) guide decision-makers and donors on the design of more sustainable seed system interventions for VPCs. The framework can be used to analyze past interventions and will be useful for planning future VPC seed programs. ARTICLE HISTORY

Banana bunchy top virus (BBTV) is a six-component ssDNA virus (genus Babuvirus, family Nanoviridae) transmitted by aphids, infecting monocots (mainly species in the family Musaceae) and likely originating from South-East Asia where it is frequently associated with self-replicating alphasatellites. Illumina sequencing analysis of banana aphids and leaf samples from Africa revealed an alphasatellite that should be classified in a new genus, phylogenetically related to alphasatellites of nanoviruses infecting dicots. Alphasatellite DNA was encapsidated by BBTV coat protein and accumulated at high levels in plants and aphids, thereby reducing helper virus loads, altering relative abundance (formula) of viral genome components and interfering with virus transmission by aphids. BBTV and alphasatellite clones infected dicot Nicotiana benthamiana, followed by recovery and symptomless persistence of alphasatellite, and BBTV replication protein (Rep), but not alphasatellite Rep, induced leaf chlorosis. Transcriptome sequencing revealed 21, 22 and 24 nucleotide small interfering (si)RNAs covering both strands of the entire viral genome, monodirectional Pol II transcription units of viral mRNAs and pervasive transcription of each component and alphasatellite in both directions, likely generating double-stranded precursors of viral siRNAs. Consistent with the latter hypothesis, viral DNA formulas with and without alphasatellite resembled viral siRNA formulas but not mRNA formulas. Alphasatellite decreased transcription efficiency of DNA-N encoding a putative aphid transmission factor and increased relative siRNA production rates from Rep- and movement protein-encoding components. Alphasatellite itself spawned the most abundant siRNAs and had the lowest mRNA transcription rate. Collectively, following African invasion, BBTV got associated with an alphasatellite likely originating from a dicot plant and interfering with BBTV replication and transmission. Molecular analysis of virus-infected banana plants revealed new features of viral DNA transcription and siRNA biogenesis, both affected by alphasatellite. Costs and benefits of alphasatellite association with helper viruses are discussed.

In November 2009, many farmers in Abia State were alarmed by complete destruction of their taro (Colocasia esculenta (L.) Schott.) crop. Symptoms, suggestive of leaf blight caused by Phytophthora colocasiae Raciborski (2), began as small, brown, water-soaked lesions that rapidly enlarged to form large, dark brown, coalescing lesions, sometimes with orange host exudations. White sporulation was evident on the lesion surface under wet conditions. The pathogen caused rapid defoliation and killed plants. The epidemic was widespread in 2010 during the rainy season (April to November) in all taro-growing areas of Nigeria. Diseased leaves were collected from taro in Iwo Village near Ibadan, cut into 4-cm2 pieces, washed in several changes of sterile water, and incubated in petri dishes lined with wet filter paper at 22°C. Newly produced sporangia were collected from the incubated leaves and plated on a selective medium (1). Sporangia were hyaline, papillate, and measured 25 to 55 × 15 to 30 μm. Zoospores encysted within 30 min after release; cysts were 9.7 to 19.5 μm in diameter. Sporangia and zoospore formation were induced in water and by chilling, respectively (1). Two leaves each of three 1-month-old taro and three Xanthosoma plants (both unknown clones) and six detached leaves of taro were inoculated with a 1 × 105/ml zoospore suspension of isolates PC01 and PC02. Detached leaves were incubated in moist chambers at 22°C. Plants were covered with polyethylene bags for 12 h after inoculation and maintained in a screenhouse. Water-soaked lesions appeared on detached leaves within 24 h postinoculation and the leaves were completely rotted 48 h later. All inoculated attached leaves of taro, but not Xanthosoma, showed typical leaf blight symptoms including abundant sporangial production. Noninoculated control detached leaves and plants were disease free. Sporangia from detached and attached inoculated leaves, when plated on selective medium, produced typical P. colocasiae colonies. The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1 and ITS4 primers (3). Amplicons (786 bp) were sequenced in both directions and submitted to GenBank (Accession Nos. HQ602756, HQ602757, HQ602758, and HQ602759). A BLASTn search revealed 99% similarity to a P. colocasiae strain of the Pacific Region (Accession No. GU111604), but only 94% similarity to a P. colocasiae strain from India (Accession No. GQ202149). The sequence analysis, morphological characteristics, and pathogenicity test confirmed the taro leaf blight pathogen as P. colocasiae. There are previous reports of occurrence of taro blight-like disease attributed to P. colocasiae in Ethiopia, Equatorial Guinea (1), and more recently in Cameroon, but comprehensive details on pathogen or disease are not available. To our knowledge, this is the first confirmed record in Nigeria of P. colocasiae causing taro blight. This disease poses a serious threat to the production and biodiversity of this important food crop. Urgent interventions are necessary to halt this emerging epidemic in West and Central Africa. References: (1) Phytophthora colocasiae, In: CABI-Crop Protection Compendium. CAB International, Wallingford, UK, 2005. (2) P. S. Tsao. Page 219 in: Phytophthora: Its Biology, Taxonomy, Ecology and Pathology. The American Phytopathological Society. St. Paul, MN, 1983. (3) T. J. White et al. Page 315 in: PCR Protocol: A Guide to Methods and Applications. Academic Press, London. 1990.

Taro (Colocasia esculenta (L.) Schott) is an important food crop cultivated for its edible tubers in Ghana. In May 2009, outbreaks of a destructive leaf disease were observed on several taro farms in the Atiwa, East-Akim, Fanteakwa, West-Akim, and New Juaben districts of the Eastern Region of Ghana. Symptoms began on leaves as small, brown, water-soaked lesions that enlarged and coalesced into large lesions with yellow exudate, ultimately leading to the defoliation and death of plants. Symptoms were suggestive of taro leaf blight (TLB) caused by Phytophthora colocasiae Raciborski (3). By August 2010, the disease had spread to other taro-growing regions in Ghana. To identify the pathogen, leaf tissue from lesion margins were excised and plated on carrot agar and V8 selective media for Phytophthora and incubated at 27°C for 5 days (2). Growth from diseased tissue was used for morphological characterization. Sporangia were ovoid, hyaline, papillate, caducous, 30 to 60 × 17 to 28 μm, and pedicels were 3.5 to 10 μm long. Genomic DNA was isolated from pure cultures of two isolates, PCg11-2 from Oseim (6°15′N, 0°27′E) and PCg11-5 from Oyoko (6°8′N, 0°17′W). Ribosomal DNA ITS1, 5.8S and ITS2 were amplified by PCR using the ITS1 and ITS4 primers (4). The resultant 784-bp amplicons were sequenced (GenBank Accession Nos. JN662439 and JN662440). Sequences of both isolates were identical. A BLASTn search of these sequences revealed maximum homology of 99% with the sequence of P. colocasiae strains from blighted taro leaves in Nigeria (GenBank Accession No. HQ602756), Hawaii (GenBank Accession No. GU258997), and several strains in Asia and the South Pacific. On the basis of morphological characteristics and nucleotide homology, the isolates were identified as P. colocasiae. To fulfill Koch's postulates, 30 leaf discs from 3-month-old plants were inoculated with 10 μl of a suspension of 3 × 105 zoospores per ml (2). Leaf discs were incubated in the dark at 27°C on wet foam in plastic trays for 5 days. All inoculated discs developed blight symptoms similar in appearance to those observed on diseased taro in the fields. Control discs remained asymptomatic. P. colocasiae was reisolated from leaf discs and its identity confirmed by morphological characteristics. To our knowledge, this is the first report of TLB and P. colocasiae in Ghana. Occurrence of TLB was recently reported in Nigeria (1). The recent occurrence of TLB in both Nigeria and Ghana threaten the taro-growing regions of West and Central Africa. Disease surveys and a management strategy that includes resistant varieties are urgently needed. References: (1) R. Bandyopadhyay et al. Plant Dis. 95:618, 2011. (2) A. Drenth and B. Sendall. Practical Guide to Detection and Identification of Phytophthora. Version 1.0. CRC for Tropical Plant Protection. Brisbane, Australia, 2001. (3) M. Raciborski. Java Batavia Bull. 19:189, 1900. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, CA, 1990.

In the present research work, 300 meat samples (50 beef, 50 carabeef, 50 chevon, 50 mutton, 50 pork and 50 chicken) collected from the municipal slaughter houses and the retail meat shops from Hyderabad Karnataka region of Karnataka state, India, were analyzed for the microbiological quality; standard plate count and isolation and confirmation of Staphylococcus, Salmonella, E. Coli, Listeria and Clostridium by selective plating, microscopic examination and biochemical characterization. As per Food Safety and Standards (FSS) regulations 2011, of the samples analyzed, 89 (29.66%) (21 beef, 26 carabeef, 9 chevon, 7 mutton, 14 pork and 7 chicken) samples exceeded the limit of 10,000 CFU/gram of total viable count. Twenty (6.66%) samples (8 beef, 9 carabeef and 3 pork) exceeded the limit for Staphylococcus (100/gram maximum), 15 (5%) samples (9 pork, 4 chicken and 2 mutton) exceeded the limit for Salmonella (absent in 25 gram) and 22 (7.33%) samples (11 pork, 4 chicken, 4 beef and 3 carabeef) exceeded the limit for E. Coli (100/gram maximum). None of the samples were positive for Listeria and Clostridium spp. The finding in this study specifies the probable contamination during farming and on-floor slaughtering and accentuates the requirement of the upgrading the municipal slaughter houses and training of retail outlet sellers.