Hopp til hovedinnholdet

Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2021

To document

Abstract

Plant-parasitic nematodes (PPN) cause significant yield reduction in commercial pineapple (Ananas comosus) worldwide. In Kenya, few nematode studies have been conducted, although the main commercial pineapple producer has sole dispensation to use Telone II (1,3-Dichloropropene) indicating the magnitude of the nematode problem. This study was conducted with the aim to investigate the population densities and diversity of nematodes in two commercial plantations with two contrasting management practices. We additionally assessed the influence of crop age and compared this with nearby smallholder pineapple production systems. Soil and root samples were collected from fields of different ages in each commercial plantation and from 29 smallholder fields. A total of 18 genera were associated with pineapple, with a relatively greater diversity found in smallholder than commercial farms. The most prevalent genus was Meloidogyne spp. (M. javanica) followed by Helicotylenchus spp., Tylenchus spp. and Aphelenchoides spp. PPN densities were higher in relatively older fields of 24 and 36 months than from fallow and 3-month-old fields. Regression analysis additionally demonstrated the rise of PPN densities with age of pineapple fields, especially Meloidogyne spp., while free-living nematode densities declined. This study provides an indication of the high level of PPN infection in pineapple in Kenya, which would constitute an important factor contributing to low yields. The study confirms an obvious need for pineapple producers to control PPN to improve crop yields.

Abstract

For a 100% organic value chain, we need more varieties suitable for organic cultivation. Varieties bred for organic growing is a challenge in small markets. Many breeding goals are equal for organic and conventional cereals. Hence, accessions failing qualification as commercial varieties may perform well in organic growing. A field experiment over two years was performed at two growing sites to compare 25 accessions of spring wheat, ranging from old heritage varieties to modern breeding lines. We assessed yield and agronomic characteristics, artisan bread baking quality and sensory characteristics. Modern accessions gave best yields. Old varieties had smaller kernels, less grain filling, lower falling numbers and SDS-sedimentation volumes, but higher concentrations of minerals, although the growing site has a strong effect. Bread from modern accessions performed best in a baking test. Several sensory characteristics such as juiciness, chew resistance, firmness, acid taste and vinegar odor varied between varieties. Heritage varieties have an important cultural value, and many consumers are willing to pay a significant premium price for such products. A premium price is required, since yield levels are often considerably lower.