| Přispěvatelé: |
Barros, Ana Isabel Faria Ribeiro, Ramalho, José Cochicho, Massinga, Rafael Abel Dos Santos, Lage, Luís Filipe |
| Popis: |
Cowpea, Vigna unguiculata (L.) Walp, is among the most important grain legumes in Africa. Its nutritional value coupled with the high plasticity places this legume in a unique position to help avert Sub-Saharan African (SSA) food insecurity and poor protein consumption. Therefore, improving farmer’s access to locally accepted and high yielding genotypes is a major challenge. To achieve this goal, significant investment in breeding new elite cowpea varieties must be made. For this regard, Africa can take advantage of its vast repository of germplasm as the basis to breed and engineer high yielding and locally adapted varieties. Nevertheless, research on the genetic variability and drought avoidance mechanisms among available and widely used cowpea landraces in rural Africa is incipient. To generate information that could aid future breeding and development of agronomic guidelines, the current study was conducted to determine the genetic variability and understand drought response mechanisms on cowpeas landraces within central Mozambique. Cowpea germplasm collected in six Central Mozambique agroecological regions: Manica (R3, R4,), Tete (R6, R10), Sofala (R5), Zambezia (R7, R10), was characterized under rain feed conditions to evaluate their genetic diversity through the analysis of morphological traits. Results from this study showed that Central Mozambique cowpea genotypes retain a high level of morphological diversity without a specific geographical pattern, which suggests the existence of a high gene flow with Maringué landraces, seem to be the most divergent and promising in terms of grain related traits. Complementary, results from the genetic diversity of this core collection assessed using molecular microsatellite markers indicate the existence of four genetic groups, with no specific geographic pattern. This suggests the presence of gene flow between landraces and that the high genetic diversity found in Central Mozambique sustains the importance of local genetic resources and the need to protection the local germplasm and use it smartly to enhance genetic diversity in modern varieties of cowpea locally and worldwide. Based on the results, three accessions of contrasting drought tolerance were further selected to evaluate the drought responses using an integrated physiological and metabolomics analysis to identify drought tolerance probes. For this study, an integrated throughput and targeted characterization of the physiological (leaf gas ex- change, photosynthetic pigments, chl a fluorescence) and biochemical (RuBisCO activity, and GC-TOF-MS primary metabolite profiling coupled to a PLS-DA) drought response pathways to support the identification and selection of drought tolerant cowpea landraces was used. This is a pioneering approach to aid the characterization of Africa’s and central Mozambique highly diverse cowpea germplasm and constitutes a first step towards a breeding strategy aiming at obtaining high yield, and drought tolerant elite varieties. The results of this work encourage a broad network of on-farm activities that should be enrolled in a socioeconomic framework to manage and complement gene bank collections. This is also the best way to prevent genetic erosion while maintaining and expanding the cultivation of cowpea in a wide range of environmental conditions. The results also provide guidance about which landraces should be prioritized for in situ and ex situ conservation of cowpea, and to boost the value of this crop as an important native genetic resource for food security in Mozambique. However, to take advantage of the identified genetic variability and of the integrated characterization and screening developed in this research, strong decision support systems at all levels - research, community, farm and policy levels are needed to help bring researchers, farmers and policy makers together to define clear intervention priorities and the most effective pathways to ignite a long-lasting change of practice. However, for this to happen, context specific and systems level interventions rooted in human centred design will be needed to collectively understand, identify, and promote best-fit solutions to each problem in hand. Thus, the active involvement of farmers in co-designing technological intervention that are likely to add-value to their on-going systems and consequently improve their performance and adaptability to external shocks is critical not only to build ownership but to establish effective local peer-innovation platforms. |
