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Plant genetic resources and germplasm are fundamental sources for plant breeding, and the assessment of the genetic diversity among germplasm accessions is useful to facilitate the more efficient use of plant genetic resources. The current study was carried out to estimate genetic variability, heritability and genetic advance to select genotypes and traits for breeding. In the experiment undertaken, fifty-three sorghum landraces were evaluated for selected seven qualitative and fourteen quantitative traits using randomized complete block design in three repetitions. There were differences (p< 0.001) among landraces for all assessed traits indicating a high degree of variability. Higher genotypic coefficient of variation and phenotypic coefficient of variation were observed for grain weight of main panicle, number of leaf remain green and weight of main panicle. Estimates of phenotypic variances were higher than genotypic variance for all the studied quantitative traits. High heritability coupled with high genetic advance as per cent of mean was observed for majority of assessed traits. This study allowed noting a positive relationship between number of day to flowering with plant height and stay green, and a negative correlation between plant height and weight of main panicle. A dendrogram revealed four main clusters of genotypes. The D2 statistics confirmed the highest inter-cluster distance between all clusters. This indicated existence of the possibility to improve genotypes through hybridization from any pair of clusters.

Good practice in post-harvest operations depends on the contamination of groundnuts (Arachis hypogaea) by mycotoxins. The objective of this study is to identify farmers' practices that pose a risk to the post-harvest preservation of the fruits of Arachis hypogaea in the province of Mayo Kebbi Ouest. Data collection was carried out using a farmer survey sheet based on a questionnaire on drying and storage techniques and losses related to groundnut harvesting. The study revealed that the fruits of Arachis hypogaea are dried on the fields and stored in shells or pods in polyethylene bags. The latter can be kept for up to 6 months in the shop (44%), in the attic (25.3%), in living quarters (18.7%) and both in the attic and in houses (12%). The level of post-harvest losses is due on the one hand to post-harvest diseases (60%) and the presence of insects on the crops (32%) and on the other hand to the germination of seeds (8%) after the harvest due to heavy rains. This loss on a scale of 2% to 10% is 74.7% and 10% to 50% is 25.3%. Drying and storage techniques in these localities represent a risk of mycotoxin contamination of groundnuts. Raising farmers' awareness of harvest management techniques to preserve the sanitary quality of groundnuts would be important.

Rice is one of the most widely grown and consumed cereals in Chad. However, its production decreases over the years due to bio-aggressors. This situation pushes farmers to use chemical synthetic plant protection products to remedy insect and disease attacks. These chemicals expose them to risks of poisoning and environmental pollution. To reduce the use of these chemical pesticides, extracts of Azadirachta indica, Khaya senegalensis and Boswellia dalzielii were used to treat rice seeds. These seeds were soaked separately in the different extracts used at a concentration of 50 mg/ml for one hour before sowing. The incidence and severity of the angular spot, growth and development parameters were assessed. The three types of plant extracts showed a high reduction in the incidence and severity of the disease, and improved certain growth and development parameters. These plant extracts could be used as bio-fungicides in rice cultivation.

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