RESUMEN
Magnaporthe oryzae, a devastating pathogen of finger millet (Eleusine coracana), secretes effector molecules during infection to manipulate host immunity. This study determined the presence of avirulence effector genes PWL1 and PWL2 in 221 Eleusine blast isolates from eastern Africa. Most Ethiopian isolates carried both PWL1 and PWL2. Kenyan and Ugandan isolates largely lacked both genes, and Tanzanian isolates carried either PWL1 or lacked both. The roles of PWL1 and PWL2 towards pathogenicity on alternative chloridoid hosts, including weeping lovegrass (Eragrostis curvula), were also investigated. PWL1 and PWL2 were cloned from Ethiopian isolate E22 and were transformed separately into Ugandan isolate U34, which lacked both genes. Resulting transformants harboring either gene gained varying degrees of avirulence on Eragrostis curvula but remained virulent on finger millet. Strains carrying one or both PWL1 and PWL2 infected the chloridoid species Sporobolus phyllotrichus and Eleusine tristachya, indicating the absence of cognate resistance (R) genes for PWL1 and PWL2 in these species. Other chloridoid grasses, however, were fully resistant, regardless of the presence of one or both PWL1 and PWL2, suggesting the presence of effective R genes against PWL and other effectors. Partial resistance in some Eragrostis curvula accessions to some blast isolates lacking PWL1 and PWL2 also indicated the presence of other interactions between fungal avirulence (AVR) genes and host resistance (R) genes. Related chloridoid species thus harbor resistance genes that could be useful to improve finger millet for blast resistance. Conversely, loss of AVR genes in the fungus could expand its host range, as demonstrated by the susceptibility of Eragrostis curvula to finger millet blast isolates that had lost PWL1 and PWL2. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
RESUMEN
It is understood that the grain market pulls the seed market. The problem of low quality prompted failure of traders and processors to purchase most of the farmers' grain to subsequently drive the use of improved variety seed. The aim of this study is to identify drivers that persuade farmers to use improved variety seeds for grain production. It also assesses factors affecting market participation among small-scale farmers. Descriptive analysis, Binary Logistic model, Probit model and gross margin analysis was conducted from random selected sample of 212 individual farmers, 63 grain off-takers, 3 extension officers and 7 seeds producers through structured interviews. In additional, 80 farmers were interviewed through 10 focus group discussion. The results showed that taste, preferences and price difference between grain and seed were significant and positive drivers that influenced the decision of farmers to use improved varieties at 47% and 0.007%, respectively. Factors such as group membership and farm size were significantly positive affecting farmer's market participation while age was negatively significant affecting farmer's market participation. Gross margin was computed to compare the profit margin between users and non-users of improved variety seeds, where users had high profit margin (530 979.89Tsh/Ha) compared to non-users (472 885.94Tsh/Ha), because non-users incurred high seed cost (54 504.84Tsh/15kg) compared to users of improved variety seeds (39 329.94Tsh/kg). Also, users obtained high grain revenue compared to non-user at 1 353 268.37Tsh and 848 249.11Tsh, respectively. Efforts should be made by value chain actors and other agricultural actors to support farmers based on market demand so they could benefit from high grain quality, quantity and promising grain market.
RESUMEN
Drought is a devastating environmental stress in agriculture and hence a common target of plant breeding. A review of breeding progress on drought tolerance shows that, to a certain extent, selection for high yield in stress-free conditions indirectly improves yield in water-limiting conditions. The objectives of this study were to (i) assess the genotype × environment (GE) interaction for grain yield (GY) and other agronomic traits for maize (Zea mays L.) across East African agro-ecologies; and (ii) evaluate agronomic performance and stability in Uganda and Tanzania under optimum and random drought conditions. Data were recorded for major agronomic traits. Genotype main effect plus GE (GGE) biplot analysis was used to assess the stability of varieties within various environments and across environments. Combined analysis of variance across optimum moisture and random drought environments indicated that locations, mean-squares for genotypes and GE were significant for most measured traits. The best hybrids, CKDHH1097 and CKDHH1090, gave GY advantages of 23% and 43%, respectively, over the commercial hybrid varieties under both optimum-moisture and random-drought conditions. Across environments, genotypic variance was less than the GE variance for GY. The hybrids derived from doubled-haploid inbred lines produced higher GY and possessed acceptable agronomic traits compared with the commercial hybrids. Hybrid CKDHH1098 ranked second-best under optimum-moisture and drought-stress environments and was the most stable with broad adaptation to both environments. Use of the best doubled-haploids lines in testcross hybrids make-up, well targeted to the production environments, could boost maize production among farmers in East Africa.