Early leaf spot (ELS) is one of the major biotic constraints of groundnut production in West and Central Africa. A study using 6 × 6 F2 full diallel populations from six parents (NAMA, B188, PC79-79, QH243C, TS32-1, and CN94C) was conducted to assess the mode of inheritance of ELS resistance traits. The F2 and parents were grown in a randomized complete block design with three replications. Data was collected on ELS disease severity, and an area under disease progress curve (AUDPC) was estimated. The results revealed that additive and non-additive gene actions were involved in the inheritance of the ELS resistance traits, but additive gene action was predominant. Significant reciprocal cross effect was observed, suggesting cytoplasmic effect on ELS resistance. Graphical analysis also revealed the predominance of additive gene action for ELS resistance. The results suggest that early generation selection should be effective for ELS resistance. Looking at the distribution of array points along with the regression line, parental lines NAMA, PC79-79, and B188 would be suitable as good donors in an ELS disease resistance breeding program.

Pulses play important roles in providing proteins and essential amino-acids, and contribute to soils’ nutrients cycling in most smallholder farming systems in Sub-Saharan Africa (SSA). These crops can be promoted to meet food and nutrition security goals in low-income countries. Here, we investigated the status of Kersting’s groundnut (Macrotyloma geocarpum, Fabaceae), a neglected pulse in West Africa. We explored its diversity, the production systems, the production constraints and farmers’ preferences in Burkina Faso and Ghana. Focus groups and semi-structured interviews were conducted in 39 villages with 86 respondents grouped in five sociolinguistic groups. Our results indicated that Macrotyloma geocarpum was produced in three cultivation systems: in the first system, farmers grew Kersting’s groundnut in fields, mostly on mounds or on ridges; in the second system, farmers grew it as field border; and in the third system, no clear tillage practice was identified. The main constraints of those farming systems included: difficulty to harvest, the lack of manpower and the damage due to high soil humidity at the reproductive stage. A total of 62 samples were collected and clustered in six landraces based on seed coat colors including cream, white mottled with black eye, white mottled with greyed orange eye, black, brown mottled, and brown. All six groups were found in the southern-Sudanian zone whereas only white mottled with black eye and black colors were found in the northern-Sudanian zone. The white mottled with black eye landrace was commonly known and widely grown by farmers. Farmers’ preferences were, however, influenced by sociolinguistic membership and the most preferred traits included high yielding, drought tolerance, and resistance against beetles. These findings offer an avenue to develop a relevant breeding research agenda for promoting Kersting’s groundnut in Burkina Faso and Ghana.

The present experiment was conducted in Mali to study the genetic variability and correlation of early leaf spot (ELS) resistance parameters and agro-morphological traits in groundnut using two F3 populations from crosses QH243C X NAMA and TS32-1 X NAMA. Estimates of genotypic coefficient of variation and phenotypic coefficient of variation revealed high value for pod yield, kernel yield, and ELS score at 60 and 80 days after sowing for the cross QH243C X NAMA. Low-to-moderate GCV and PCV were obtained for the remaining traits for both crosses. High heritability values coupled with high genetic advance as percentage of mean recorded for ELS_II, defoliation percent, pod yield in cross QH243C X NAMA; shelling percent for the cross TS32-1 X NAMA and ELS_III; and plant height, kernel yield in both crosses, indicate the significant role of additive gene action for inheritance of these traits. Correlation analysis indicated that pod and kernel yield were significant and positively correlated with 100 kernel weight and shelling percent. For cross QH243C X NAMA, kernel yield showed significant positive correlation with all ELS resistance components but the correlation was not significant for the cross TS32-1 X NAMA. Positive and significant correlation was observed between ELS resistance components themselves, suggesting that these components could be controlled by a similar polygenic system. The findings suggest that early generation selection should be effective for days to first flowering, days to 50% flowering, plant height, pod yield, kernel yield, 100 kernel weight and early leaf spot resistance which recorded the highest value of heritability in the two crosses.

Bacterial Leaf Streak (BLS) of rice caused by Xanthomonas oryzae pv. oryzicola (Xoc) is considered as the third emerging infectious disease of rice in Africa. First reported in Africa in the 1980s, the disease is now present in at least eight African countries including Burundi, Burkina Faso, Kenya, Madagascar, Mali, Nigeria, Senegal and Uganda. Yield loss caused by BLS is estimated at 20 to 30% (Sileshi and Gebeyehu, 2021). To our knowledge BLS has so far not been reported in Ivory Coast. While BLS has not been described in the adjacent rice-growing countries Ghana and Liberia, Xoc strains isolated from samples collected between 2003 and 2011 in Burkina Faso and Mali have been characterized (Wonni et al., 2014). Xoc is transmitted through rice seeds which favors its spread through rice trading (Sileshi and Gebeyehu, 2021). Given the extensive rice trade between Burkina Faso, Mali and Ivory Coast, we hypothesized that BLS might also be present in this country. Field surveys were carried out across Ivory Coast in October 2018. Typical symptoms of the disease, e.g. translucent lesions in the form of yellow-brown to black streaks with sometimes visible droplets of exudates on the leaf surface, were observed in the area of Korhogo. 5cm-long leaf pieces were successively disinfected, rinsed in sterile water, and then ground using the Qiagen Tissue Lyser System (QIAGEN, Courtaboeuf, France). Leaf powder was resuspended in 1.5 ml of sterile water and incubated at room temperature for 30 minutes. Then, 10 μl of the suspension was streaked on semi-selective PSA medium and incubated at 28 ° C for 3 to 7 days. Colonies characteristic of Xoc, i.e. round, convex, mucous and straw yellow in color were purified from 6 individual samples from 2 distinct sites in Korhogo. To confirm their identity, isolated strains underwent a pathogenicity and molecular characterization test. The multiplex PCR developed for the identification of X. oryzae pathovars (Lang et al., 2010) revealed for all the isolates the characteristic PCR profile of Xoc (two amplicons of 324 and 691 base pairs). Strains of Xoc BLS256 and Xoo PXO99 were used as controls. The pathogenicity test was performed on 5 weeks-old plants of O. sativa cv. Azucena leaves by infiltration with a needleless syringe of a bacterial suspension at an optical density of 0.5. After 7 days of greenhouse incubation (27 ± 1°C with a 12-hour photoperiod), all infiltration points (2 infiltrations x 3 plants per isolate) developed water-soaked lesions identical to the one challenged with BLS256 while water-infiltrated leaves remained asymptomatic. These lesions were collected and subjected to the isolation and multiplex PCR processes described above, thus fulfilling Koch's postulate. Finally, three of the isolates were subjected to sequencing of the housekeeping gene gyrB by PCR amplification using the primers XgyrB1F and XgyrB1R (Young et al., 2008). Analysis of 780bp of the gyrB sequence of strains CI_k1-1, CI_k2-2 and CI_k3-2 revealed 100% identity with the gyrB sequence of Xoc reference strain BLS256 (Acc. No. CP003057) and 10 polymorphic nucleotides compared to the Xoo reference strain PXO99A (Acc. No. CP000967). To our knowledge, this is the first report of BLS in Ivory Coast supported by molecular characterization methods. New surveys in Ivory Coast and neighboring countries where the disease has not been reported will allow to implement collections and assess disease incidence as part of future control strategies.

Ginger (Zingiber officinale Rosc.) is a very important spice for rural and urban communities in Burkina Faso. Cultivation of ginger is mainly practiced by traditional farmers, and its commercialisation offers substantial income to farmers, traders and processors. The tuber contains enormous medicinal and nutritional potential, and can thus contribute to qualitative improvement of the diet of consumers. Despite the many advantages of this plant, it remained underexploited due to insufficient knowledge of cultivation methods, its cycle duration and its water requirement, which confines the crop mainly to the western region of Burkina Faso. Such under-exploitation has been exacerbated due to little attention dedicated to ginger research in the country. Therefore, preservation and improvement of ginger quality represent an important challenge for the various actors of this crop’s industry. The present review highlights the importance of ginger, its role in crop diversification, its medicinal and nutritional properties, as well as the future areas of selection and genetic improvement of this species in Burkina Faso.

Cotton breeding progress stagnation, changing production conditions, and continued high fiber quality demands are challenging the cotton industry in Burkina Faso. The F₁ populations developed by half diallel crosses between germplasm from Texas A&M AgriLife Research and Burkina Faso were evaluated for several agronomic traits. The aim was to identify the most promising parents and hybrids for further varietal improvement. Three AgriLife parents helped improve the most important targeted traits. Parent 15-3-416 reduced days to 50% flowering (−3.14 days) and shortened plant height (−22.25 cm) in hybrids while 16-2-216FQ improved their fiber percentage (+2.68%). Hybrids with Burkina Faso elite cultivar E32 as male parent and the three best AgriLife parents as the females showed good specific combining ability (SCA). FK37 × 15-10-610-7 and FK64 × 15-10-610-7 showed heterosis for earliness by reducing, respectively, days to 50% flowering (−4.27 days) or days to 50% boll opening (−3.95 days) below parent means. E32 × 16-2-216FQ and FK64 × 16-2-216FQ increased fiber percentage by +1.75% and +2.06%, respectively. FK64 × 15-3-416 increased seed index (SI) (+0.62 g) and fiber percentage (+1.19%), while maintaining other traits at the parents’ average levels. E32 × 15-3-416 showed the most heterosis for desired improvements, reducing days to 50% flowering (−4) and increasing the number of bolls/vegetative branch (+3.05), number of bolls/fruiting branch (+6.38), number of bolls/plant (+13.49), boll weight (+1.53 g), SI (+0.40 g), and fiber percentage (+1.18%). Inter-program crosses show the potential to enhance genetic diversity in Burkina Faso’s breeding program. Subsequent selection methods must be carefully applied considering the Burkina Faso breeding objectives for future cultivars.