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Sorghum ( Sorghum bicolor (L.) Moench) is an important staple food in semi-arid tropics which contribute to food security and poverty alleviation in Benin. However, its production is seriously facing enormous abiotic and biotic stresses including climate variability. To document its cultivar diversity, the impact of climate change on its production and diversity, the adaptation strategies developed by farmers and the performance of landraces, 22 villages were randomly selected and surveyed in the Department of Atakora in the northwest of Benin using participatory research appraisals (fields and granaries visit, individual and group survey using questionnaires, Four cells or distribution and extent analysis, etc.). Data were analysed through descriptive statistics (frequencies, percentages, means, etc.) to generate summaries and tables at different (villages, individuals) levels and also through multivariate analysis (cluster analysis) and the results figures. In total 8 constraints affecting sorghum production were recorded among which striga proliferation, soil poverty and climate change effects (drought; excess of rain; delay, insufficient and irregular rainfall, etc.) were the most important. Subject to synonyms, 89 sorghum landraces were inventoried and their number varied from 4 to 17 (7 on average) per village. The Shannon-Weaver diversity index (H) estimated at 3.02 indicated high sorghum diversity in the study area. Many landraces were threatened. The relatively high rates (16.7-88.2 %; 40.9 % on average) of cultivars loss recorded per village are proofs of menace of genetic erosion and necessity of developing conservation strategies. Inadaptability of cultivars to climate variability (39.6 % of abandoned landraces) was among others the most important reason justifying the loss of diversity. Crop rotations, growing of early maturing and/or drought tolerant landraces, establishment of fields in lowlands are the most important strategies developed by farmers to mitigate impacts of climate change (low productivity, increase of damages from storage insects, early drying of plant leaves etc.) on the crop. Participatory evaluation of the existing landraces led to the identification of some high-performing ones that are resistant/tolerant to diverse abiotic and biotic stresses. Farmers' cultivars preference criteria were identified and prioritized. Results of this study are useful to policy makers, agricultural extension services of the different districts, genetic resources specialists and breeders in order to improve sorghum production in Benin. [ABSTRACT FROM AUTHOR]

Sorghum [Sorghum bicolor (L.) Moench] is an important staple food crop in northern Benin. In order to assess its diversity in Benin, 142 accessions of landraces collected from Northern Benin were grown in Central Benin and characterised using 10 qualitative and 14 quantitative agromorphological traits. High variability among both qualitative and quantitative traits was observed. Grain yield (0.72–10.57 tons/ha), panicle weight (15–215.95 g), days to 50% flowering (57–200 days), and plant height (153.27–636.5 cm) were among traits that exhibited broader variability. Correlations between quantitative traits were determined. Grain yield for instance exhibited highly positive association with panicle weight (r=0.901, P=0.000) and 100 seed weight (r=0.247, P=0.000). UPGMA cluster analysis classified the 142 accessions into 89 morphotypes. Based on multivariate analysis, twenty promising sorghum genotypes were selected. Among them, AT41, AT14, and AT29 showed early maturity (57 to 66 days to 50% flowering), high grain yields (4.85 to 7.85 tons/ha), and shorter plant height (153.27 to 180.37 cm). The results obtained will help enhancing sorghum production and diversity and developing new varieties that will be better adapted to the current soil and climate conditions in Benin. [ABSTRACT FROM AUTHOR]

• Free and bound phenolic fractions were extracted from Rosa roxburghii Tratt pomace. • Free and bound polyphenols were identified in RRTP-FPF and RRTP-BPF. • RRTP-BPF and RRTP-FPF could scavenge radicals in a dose-dependent manner. • RRTP-BPF and RRTP-FPF could improve SOD and CAT activity in the living C. elegans. • Our results imply that R. roxburghii pomace is a promising source of antioxidants. Rosa roxburghii Tratt pomace (RRTP) has increasingly attracted attention due to its various nutritional ingredients and health benefits. In this study, the free phenolic fraction (RRTP-FPF) and bound phenolic fraction (RRTP-BPF) were extracted from RRTP by solvent extraction method and alkaline hydrolysis method, respectively. The composition of polyphenols in RRTP-FPF and RRTP-BPF were identified by ultra-high performance liquid chromatography equipped with an electrospray ionization and quadrupole time-of-flight mass spectrometry (UHPLC-ESI-QTOF-MS/MS). In vitro antioxidant assays indicated that RRTP-FPF and RRTP-BPF could scavenge radicals in a dose-dependent manner, and RRTP-BPF exhibited better scavenging activity than RRTP-FPF. In addition, RRTP-FPF and RRTP-BPF (20 ∼ 100 μg/mL) treatment for 24 h could significantly increase the survival rate and decrease reactive oxygen species (ROS) level of paraquat-exposed nematodes through improving the activities of superoxide dismutase (SOD) and catalase (CAT). These results suggest that RRTP could be as a good and cheap source of natural antioxidants. [ABSTRACT FROM AUTHOR]

Guinea yams (Dioscorea cayenensis-rotundata complex; D. rotundata Poir. and D. cayenensis Lam.) have been described as resulting from a process of domestication of wild yams of the section Enantiophyllum by African farmers. Although currently practised by few farmers, the process of yam domestication is still on-going in Benin. In order to document the practices used and the indigenous knowledge maintained by Nago and Fon farmers, 27 villages were surveyed. In total, 57 farmers domesticating yam were identified, and 68 yams newly domesticated (or in domestication) were collected. Fon and Nago farmers domesticate yam mainly to widen the genetic basis of the existing diversity or for simple curiosity. Among the three wild yams species (D. abyssinica Hochst. ex Kunth, D. praehensilis Benth. and D. burkilliana J. Miège) used, D. praehensilis is the most important and the most exploited. Tuber of the wild yams are collected either in the bush (most often near the village) or in the forests (far from the village) during hunting. The domestication process consists of bringing into cultivation selected individuals which go through intense vegetative multiplication and selection procedures (over a lengthy but variable period of time) that induce morphological and biochemical changes in the plant mainly at the tuber level. Individuals resulting from these manipulations were found to be, either similar or identical to known landraces or completely new based on both morphological and isozyme analysis. Because it leads to some new cultivars, this process of domestication has potential in yam breeding and appears to be a strategy that could be useful to breeders, while developing a methodology for participatory breeding of yam. [ABSTRACT FROM AUTHOR]

Using IPGRI's descriptors, 45 accessions of Guinea yams( Dioscorea cayenensis Lam./ Dioscorea rotundata Poir. complex) collectedin Cameroon were classified into six cultivar groups based on theirmorphological similarities. An identification key is proposed for thecultivar groups. Six enzymatic systems (6PGD, PGI, AAT, SKDH,PGM, EST) were also used to assess genetic variation withinthese cultivated yams. Twenty-eight genotypes were identifiedwithin the 45 accessions analysed. The clustering of accessions basedon isozyme data is very close to the one obtained using morphologicalcharacters. [ABSTRACT FROM AUTHOR]