Carbon isotope composition and the NDVI as phenotyping approaches for drought adaptation in durum wheat: Beyond trait selection

High-throughput phenotyping platforms provide valuable opportunities to investigate biomass and drought-adaptive traits. We explored the capacity of traits associated with drought adaptation such as aerial measurements of the Normalized Difference Vegetation Index (NDVI) and carbon isotope composition (\u3b413C) determined at the leaf level to predict genetic variation in biomass. A panel of 248 elite durum wheat accessions was grown at the Maricopa Phenotyping platform (US) under well-watered conditions until anthesis, and then irrigation was stopped and plot biomass was harvested about three weeks later. Globally, the \u3b413C values increased from the first to the second sampling date, in keeping with the imposition of progressive water stress. Additionally, \u3b413C was negatively correlated with final biomass, and the correlation increased at the second sampling, suggesting that accessions with lower water-use efficiency maintained better water status and, thus, performed better. Flowering time affected NDVI predictions of biomass, revealing the importance of developmental stage when measuring the NDVI and the effect that phenology has on its accuracy when monitoring genotypic adaptation to specific environments. The results indicate that in addition to choosing the optimal phenotypic traits, the time at which they are assessed, and avoiding a wide genotypic range in phenology is crucial

Spectral Characteristics of Tobacco Cultivars with Different Nitrogen Efficiency and Its Relationship with Nitrogen Use

International audienceTo investigate the relationship between spectral characteristics of tobacco cultivars and their nitrogen use characters, four tobacco cultivars with different nitrogen use efficiency were used in a 15N pot experiment. The result showed that, in the visible light range, the spectral reflectance was lower in higher nitrogen level (N2) than N1, while opposite in near infrared range. The spectral reflectance of K326 and HD were lower than ZY100 and NC89 in visible light range, which closely related to their higher chlorophyll content. Both the nitrogen utilization rate of basal fertilizer and topdressing fertilizer in HD and K326 were higher than that in ZY100 and NC89 under N1 and N2 levels. The basal fertilizer use efficiency was negatively correlated with ρ550, and significantly positively correlated with RVI (800, 550), DVI (800, 550) and NDVI (800, 550) both in N1 and N2 level. The top dressed fertilizer use efficiency was significantly positively correlated with RVI (800, 550), DVI (800, 550) and NDVI (800, 550) in N1 level. Therefore, spectral characteristics can be an important method for diagnosing tobacco nitrogen metabolism characteristics

Nitrogênio e fósforo no crescimento de plantas de ginseng brasileiro [Pfaffia glomerata(Spreng.) Pedersen] cultivadas in vitro Nitrogen and phosphorus on growth of brazilian ginseng [Pfaffia glomerata (Spreng.) Pedersen] in vitro cultured plants

O ginseng brasileiro [Pfaffia glomerata (Spreng.) Pedersen] apresenta propriedades medicinais marcantes e, por isso, atualmente, é largamente explorado de forma extrativista, tanto por parte dos coletores de ervas como pela indústria farmacêutica. Este trabalho objetivou caracterizar o efeito da variação isolada da concentração de N e P do meio MS no crescimento de plantas de P. glomerata cultivadas in vitro. Segmentos nodais de 1,0cm de comprimento e sem folhas, de plantas já estabelecidas in vitro, foram cultivados em meio MS contendo cinco concentrações (0, 25, 50, 100 e 150% da concentração padrão do meio de cultura MS) de nitrogênio ou fósforo. Aos 15 dias após a inoculação (DAI), o número de raízes e o percentual de enraizamento são maiores na concentração de N e P equivalentes a 50% daquela do meio de cultura MS. Aos 40 DAI, o crescimento em altura das brotações, número de segmentos nodais, índice de área foliar, número de folhas, matéria seca de raízes, da parte aérea e total da planta é maior na concentração de N e P, em média, próxima a 80% daquela do meio de cultura MS.<br>Brazilian ginseng [Pfaffia glomerata (Spreng.) Pedersen] has expressionable medicinal properties, and therefore, nowadays it is extensively exploited either by the herb collectors as well as the pharmaceutical industry. The aim of this work was to characterize the effect of N and P concentrations from the MS medium on growth of P. glomerata in vitro cultured plants. 1-node segment without leaves, from in vitro cultivated plants, were grown on five levels (0, 25, 50, 100, and 150% of the strength of the MS medium) of N and P. After 15 days of inoculation, root number and rooting percentage are greater on N and P levels of the MS medium with 50% strength. After 40 days of inoculation, growth, based on sprout height, number of nodal segments per plant, leave area index per plant, number of leaves per plant, dry weight of aerial parts, roots and of the whole plant, is greater when the N and P levels of the MS medium is near to 80% strength