Near-infrared spectroscopy applications for high-throughput phenotyping for cassava and yam: a review

Open Access Article; Published online: 12 Aug 2020The review aimed to identify the different high‐throughput phenotyping (HTP) techniques that used for quality evaluation in cassava and yam breeding programmes, and this has provided insights towards the development of metrics and their application in cassava and yam improvements. A systematic review of the published research articles involved the use of NIRS in analysing the quality traits of cassava and yam was carried out, and Scopus, Science Direct, Web of Sciences and Google Scholar were searched. The results of the review established that NIRS could be used in understanding the chemical constituents (carbohydrate, protein, vitamins, minerals, carotenoids, moisture, starch, etc.) for high‐throughput phenotyping. This study provides preliminary evidence of the application of NIRS as an efficient and affordable procedure for HTP. However, the feasibility of using mid‐infrared spectroscopy (MIRS) and hyperspectral imaging (HSI) in combination with the NIRS could be further studied for quality traits phenotyping

Role of root exudates and root turnover in the below-ground N transfer from Canavalia ensiformis (jackbean) to the associated Musa acuminata (banana)

Jackbean is an annual legume frequently used as green manure in tropical intercropping systems with bananas. Although the beneficial effect of nitrogen (N) release from above-ground residues on banana nutrition is well known, little information is available on the N transfer from jackbean roots before and after the above-ground harvest. The aim of this study was to assess the relative contribution of exudates and root turnover in the N transfer from jackbean to banana in a greenhouse experiment. Nitrogen transfer was studied in a 6-month trial using the 15N leaf feeding method, and estimated with a box model of 15N dilution based on the observed data of 15N content in exudates and decomposing roots. For the sowing–harvest period, the amount of N transferred from jackbean exudates represented 16% of banana N uptake and 0.7% of jackbean N uptake. Therefore, the N transfer flux via exudates was 23 times higher in terms of N input for the recipient plant than in terms of N output for the donor plant. This value, which is an index of the effectiveness of N transfer, was lower than those reported previously for other soil–plant systems in greenhouse conditions. This would be due to differences in root traits of the recipient plants. The amount of transferred N from root turnover after jackbean harvest represented 52% of banana N uptake in that period. The box model described N transfer from both legume N sources adequately (r2 = 0.92). For the whole experiment, 38% of banana N uptake was derived from jackbean (6% from exudates and 32% from root turnover), and 62% from soil N. The results indicated that N transfer from root exudates of jackbean would be a useful but minor process compared with N release from root turnover in soil. The experimental and theoretical approach proposed in this study may be useful in screening studies to assess the capability of herbaceous legumes to transfer N

BIOLOGICAL NITROGEN FIXATION AFTER STEM CUTTING IN TUBEROUS PACHYRHIZUS EROSUS

Yam bean (Pachyrhizus erosus) a tuber-forming legume, is particularly suitable for evaluating the potential availability of the plant reserve carbohydrates for nitrogen fixation (Vaillant et al., 1990,1993). The tuber of this species contains soluble sugars and starch which account, respectively, for 32 and 15% of dry weight. Furthermore, tuberous and non-tuberous plants may be avai lable in inductive or noninductive environment (Robin et al., 1990; Sorcnsen et al., 1993). A stem cutting experiment was conducted with tuberous Pachyrhizus erosus in order to evaluate its potential for maintaining N fixation after aphotosynthate stress. This paper report the effects of such a treatment on the Acetylene Reduction Assay (ARA) of nodules and on the concentration of N fixation products in underground organs

Etude comparée jours longs/jours courts de l'effet d'un traitement à la chaleur de la tige de Pachyrhizus erosus (L.)

International audienceNous avons étudié l'influence de la destruction d'un anneau de phloéme par un traitement à la chaleur de la tige, sur la teneur en glucides et l'activité nitrogénase des nodosités de Pachyrhizus erosus. Le traitement a interrompu la translocation des assimilats de la partie aérienne de la plante vers le système racinaire, mais a peu d’effets sur la photosynthèse. En jours longs, l’activité de fixation des nodosités et leur teneur en saccharose sont réduites de 65% après 5h. En jours courts par contre, l’activité de fixation des nodosités n’est réduite que de 20% après 5h. Le saccharose décroît régulièrement dans les nodosités puis ré-augmente. Cette différence de réponse physiologique au stress est liée la présence en jours courts d’un tubercule qui joue un rôle tampon dans la fourniture de substrats énergétiques pour l’activité de fixation des nodosités

Dynamics of nonstructural carbohydrates and biomass yield in a fodder legume tree at different harvest intensities

International audienc

Dynamics of nonstructural carbohydrates and biomass yield in a fodder legume tree at different harvest intensities

International audienc