Screening of cowpea germplasm for resistance to Striga gesnerioides in Niger

The parasitic weed, Striga gesnerioides, is a major constraint to cowpea production in sub-Saharan Africa. It causes significant yield reductions of cowpea, especially in dry areas. The objective of this study was to evaluate the response of 80 genotypes to Striga gesnerioides under natural infestation. The results showed significant variations in the resistance of cowpea lines to Striga; lines IT93K-693-2, IT99K-573-1-1 and IT98K-205-8 being free from Striga infestation; while lines 2491-171, 2472-154 and Suvita-2 supported few Striga shoots. The other lines supported more and varied numbers of emerged Striga shoots. The reduction of yield due to Striga infestation was more pronounced for the susceptible genotypes as compared to the resistant and tolerant lines. The high level of resistance observed in some breeding lines can be exploited in breeding cowpea for resistance to Striga. Principal Component Analysis (PCA) and clustering grouped the genotypes in three main clusters as follow: (i) high yielding and tolerant to Striga (ii) moderate yielding and resistant (iii) low-yielding and susceptible.L\u2019herbe parasitaire, Striga gesnerioides est une contrainte majeure de la production du ni\ue9b\ue9 en Afrique subsaharienne. Elle cause des r\ue9ductions de rendement du ni\ue9b\ue9 tr\ue8s importantes dans les zones arides. Un criblage en vue d\u2019\ue9valuer la r\ue9action de 80 g\ue9notypes sous infestation naturelle du Striga a \ue9t\ue9 conduit au champ. Les r\ue9sultats ont montr\ue9 qu\u2019il y a des diff\ue9rences significatives dans la r\ue9sistance des lign\ue9es du ni\ue9b\ue9 au Striga. Les lign\ue9es du ni\ue9b\ue9 IT93K-693-2, IT99K-573-1-1 et IT98K-205-8 \ue9taient indemnes de pousses \ue9merg\ue9es du Striga tandis que les lign\ue9es 2491-171, 2472-154 et Suvita-2 ont support\ue9 peu de pousses \ue9merg\ue9es du Striga. Les autres lign\ue9es ont support\ue9 des nombres vari\ue9s de pousses \ue9merg\ue9es du Striga. L\u2019effet de l\u2019infestation du Striga a entrain\ue9 une r\ue9duction du rendement des g\ue9notypes sensibles compar\ue9s aux r\ue9sistants et aux tol\ue9rants. Le niveau \ue9lev\ue9 de r\ue9sistance observ\ue9 chez certaines lign\ue9es peut \ueatre exploit\ue9e dans l\u2019am\ue9lioration de la r\ue9sistance du ni\ue9b\ue9 au Striga. L\u2019analyse du composant principal et la hi\ue9rarchisation ont permis de grouper les g\ue9notypes en 3 principales grappes\ua0comme suit\ua0: (i) hautement productriceset tol\ue9rantes au Striga (ii) moyennement productrices et r\ue9sistantes (iii) faiblement productrices et sensibles

Energy Efficiency in Cable Shovel Operations

This chapter seeks to establish the current knowledge on energy efficiency of cable shovel operations. Additionally, the chapter uses a review of the literature to make recommendations for industrial best practices and for future research to address identified gaps in the literature. The chapter first presents the fundamentals of cable shovel operations and the factors that affect the energy efficiency of shovel operations. Subsequently, the chapter presents an overview of the latest research on cable shovel energy efficiency, which is used as the basis for the recommendations. The chapter recommends that industry practitioners should use the right drive systems for their cable shovels, use data analytics to understand shovel energy efficiency, and carefully evaluate the costs and benefits of energy efficiency initiatives. The chapter also recommends that future research on shovel energy efficiency should: (i) establish theoretical benchmarks for cable shovel operations; (ii) account for human factors in the design of operator guidance systems to assist operators during shovel operations; and (iii) evaluate how effective operator training programs are in improving shovel energy efficiency