Combining High Yields and Blast Resistance in Rice (Oryza spp.): A Screening under Upland and Lowland Conditions in Benin

The future security of the supply of rice for food in Africa depends on improving the level of local production to achieve self-sufficiency. In order to cope with the existing gap between production and actual demand, combining a high level of rice blast tolerance and a high-yield potential is necessary. The current study was conducted under upland and lowland conditions in Benin to gain insight into the performance of selected blast-resistant accessions along with some currently grown varieties. This study revealed a high phenotypic variability among these accessions. Furthermore, differences in the performance of these accessions under lowland and upland conditions were observed. Principal component analysis showed their grouping in three clusters. The analysis also demonstrated a high yield potential among the blast-resistant rice accessions whether they were Oryza sativa or O. glaberrima. Furthermore, there was a significant correlation between yield and both spikelet fertility and growth cycle duration. In conclusion, the present study identified promising rice accessions for future breeding. High phenotypic variability in combination with interesting traits can help to develop new resilient varieties. Finally, when the traits correlate with yield, they can be used as markers for an early screening method for identifying promising accessions at an early stage

Ethnobotanical characterization of scarlet eggplant (Solanum aethiopicum L.) varieties cultivated in Benin (West Africa)

Open Access Article; Published online: 12 Jun 2021The African eggplant (Solanum aethiopicum L.) is an important traditional vegetable cultivated in tropical regions for its edible fruits. In the Benin Republic, S. aethiopicum is mainly cultivated by rural farmers for food and for its use in traditional medicine. Assessing varietal diversity, endogenous knowledge, production constraints and farmers' preference criteria are of great importance for promotion and conservation purposes. Using rural appraisal tools and methods, an ethnobotanical study was conducted in 680 households across 92 villages. A total of 60 local cultivars were collected and documented in the surveyed sites. We documented 15 farmers’ criteria for agronomic (57.88% of responses), culinary (28.51%) preference, and for economic (13.61%) aspects. Several constraints related to eggplant production in Benin were also recorded. The low market demand (27% of responses), lack of high-yielding cultivars (11.08% of responses), low fruit storability (10.67%), low productivity (9.84%), soil poverty (8.43%), susceptibility to high soil moisture (8.02%), pests (9.56%), diseases (8.45%), and drought (6.38%) appeared to be the most important constraints of the eggplant production system in Benin. In addition to synthetic pesticides, the eggplant farmers use botanical plant extracts such as extracts from Azadirachta indica (Meliaceae) and Hyptis suaveolens (Lamiaceae). It appears that eggplant production is still traditional and is of limited use in Benin. Finally, the currently collected germplasm was proposed for further evaluation using morphological and molecular markers to provide breeders with traits of interest for developing better eggplant varieties and hybrids that are suitable for local environmental conditions and production systems

White Guinea yam (Dioscorea rotundata Poir.) landraces trait profiling and setting benchmark for breeding programs in the Republic of Benin

Open Access Journal; Published online: 17 Aug 2022To meet the high demand for white Guinea yam, there is a need to develop and release improved varieties to farmers. Unfortunately, low rate of adoption of most of the improved yam varieties by both producers and consumers was observed. Information regarding agronomic characteristics and food qualities of popular white Guinea yam landraces with high market value are not available to establish minimum standards to be considered by breeding programs. To fill this gap, surveys using rural appraisal tools were carried out in 20 villages and 16 markets throughout Benin. Data on the agronomic performance suggested that for an improved variety to be adopted by Beninese farmers it should have a minimum yield of 4.16 ± 0.15 kg per mound, and average number of marketable tubers of 1.23 ± 0.05, a mean tuber length of 36.41 ± 1.22 cm, and a minimum diameter of 25.44 ± 1.16 cm. The sensorial attributes for boiled and pounded tubers of this improved variety should have minimum score of 3.16 for texture, 0.75 for softness, 3.75 for elasticity, and 1.34 for colour during the sensory evaluation. The improved variety must also have a minimum average severity score of 1.1 for yam mosaic virus disease, 1.33 for anthracnose and 1 for nematodes. Landraces Amoula, Laboko, and Djilaadja should be considered as the standard for yield, sensory attributes, and tolerance to pest and diseases while landraces Danwari, Kodjewe, Mondji, and Gnidou should be characterized as possessing good flowering and fruit setting capacities for breeding programs

Exploring genetic diversity and disease response of cultivated rice accessions (Oryza spp.) against Pyricularia oryzae under rainfed upland conditions in Benin

The main goal of this study is to gain insight into the relationship between the genetic profile of cultivated rice (Oryza spp.) accessions and their resistance to rice blast. Therefore, the genetic and phenotypic variability of a set of 350 cultivated rice accessions originating from Africa (Benin, Mali and Nigeria, Ivory Coast etc.) was examined. Seventy-seven fluorescent amplified fragment polymorphism (AFLP) markers were used to gain insight into the genetic variation and to classify the germplasm collection. In addition, the rice germplasm was assessed for its resistance to blast disease caused by Pyricularia oryzae in upland field conditions. Huge differences in responses of rice accessions to P. oryzae were observed, ranging from highly susceptible to highly resistant. Twelve percent of all accessions were highly resistant to P. oryzae. Based on their AFLP marker profile these highly resistant accessions could be separated from the other accessions. Stepwise regression revealed that the best prediction of the blast resistance level was achieved with a maximum number of 13 AFLP markers. Marker CTA22 was the most important for accurate prediction of blast resistance, this marker was present in all highly resistant accessions. It can be concluded that AFLP markers are a valuable tool to screen rice accessions for their susceptibility towards blast disease and that, based on a subset of markers, it is possible to predict the resistance to rice blast

Analysis of population structure and genetic diversity reveals gene flow and geographic patterns in cultivated rice (O. sativa and O. glaberrima) in West Africa

To fully exploit the diversity in African rice germplasm and to broaden the gene pool reliable information on the population genetic diversity and phenotypic characteristics is a prerequisite. In this paper, the population structure and genetic diversity of 42 cultivated African rice (Oryza spp.) accessions originating from West Africa (Benin, Mali and Nigeria, Liberia etc.) were investigated using 20 simple sequence repeats (SSR) and 77 amplified fragment length polymorphisms (AFLP). Additionally, field trials were set up to gain insight into phenotypic characteristics that differentiate the genetic populations among rice accessions. The analysis revealed considerably high polymorphisms for SSR markers (PIC mean = 0.78) in the germplasm studied. A significant association was found between AFLP markers and geographic origin of rice accessions (R = 0.72). Germplasm structure showed that Oryza sativa accessions were not totally isolated from Oryza glaberrima accessions. The results allowed identification of five O. glaberrima accessions which grouped together with O. sativa accessions, sharing common alleles of 18 loci out of the 20 SSR markers analyzed. Population structure analysis revealed existence of a gene flow between O. sativa and O. glaberrima rice accessions which can be used to combine several interesting traits in breeding programs. Further studies are needed to clarify the contributions of this gene flow to valuable traits such as abiotic and biotic stresses including disease resistance