Multispectral and thermal infrared data, visual scores for severity of common rust symptoms, and genotypic single nucleotide polymorphism data of three F2-derived biparental doubled-haploid maize populations.

Three F2-derived biparental doubled haploid (DH) maize populations were generated for genetic mapping of resistance to common rust. Each of the three populations has the same susceptible parent, but a different resistance donor parent. Population 1 and 3 consist of 320 lines each, population 2 consists of 260 lines. The DH lines were evaluated for their susceptibility to common rust in two years and with two replications in each year. For phenotyping, a visual score (VS) for susceptibility was assigned. Additionally, unmanned aerial vehicle (UAV) derived multispectral and thermal infrared data was recorded and combined in different vegetation indices ("remote sensing", RS). The DH lines were genotyped with the DarTseq method, to obtain data on single nucleotide polymorphisms (SNPs). After quality control, 9051 markers remained. Missing values were "imputed" by the empirical mean of the marker scores of the respective locus. We used the data for comparison of genome-wide association studies and genomic prediction when based on different phenotyping methods, that is either VS or RS data. The data may be interesting for reuse for instance for benchmarking genomic prediction models, for phytopathological studies addressing common rust, or for specifications of vegetation indices.

Use of remote sensing for linkage mapping and genomic prediction for common rust resistance in maize.

Breeding for disease resistance is a central component of strategies implemented to mitigate biotic stress impacts on crop yield. Conventionally, genotypes of a plant population are evaluated through a labor-intensive process of assigning visual scores (VS) of susceptibility (or resistance) by specifically trained staff, which limits manageable volumes and repeatability of evaluation trials. Remote sensing (RS) tools have the potential to streamline phenotyping processes and to deliver more standardized results at higher through-put. Here, we use a two-year evaluation trial of three newly developed biparental populations of maize doubled haploid lines (DH) to compare the results of genomic analyses of resistance to common rust (CR) when phenotyping is either based on conventional VS or on RS-derived (vegetation) indices. As a general observation, for each population × year combination, the broad sense heritability of VS was greater than or very close to the maximum heritability across all RS indices. Moreover, results of linkage mapping as well as of genomic prediction (GP), suggest that VS data was of a higher quality, indicated by higher -logp values in the linkage studies and higher predictive abilities for genomic prediction. Nevertheless, despite the qualitative differences between the phenotyping methods, each successfully identified the same genomic region on chromosome 10 as being associated with disease resistance. This region is likely related to the known CR resistance locus Rp1. Our results indicate that RS technology can be used to streamline genetic evaluation processes for foliar disease resistance in maize. In particular, RS can potentially reduce costs of phenotypic evaluations and increase trialing capacities.

Radiative transfer model inversion using high-resolution hyperspectral airborne imagery - Retrieving maize LAI to access biomass and grain yield.

Mapping crop within-field yield variability provide an essential piece of information for precision agriculture applications. Leaf Area Index (LAI) is an important parameter that describes maize growth, vegetation structure, light absorption and subsequently maize biomass and grain yield (GY). The main goal for this study was to estimate maize biomass and GY through LAI retrieved from hyperspectral aerial images using a PROSAIL model inversion and compare its performance with biomass and GY estimations through simple vegetation index approaches. This study was conducted in two separate maize fields of 12 and 20 ha located in north-west Mexico. Both fields were cultivated with the same hybrid. One field was irrigated by a linear pivot and the other by a furrow irrigation system. Ground LAI data were collected at different crop growth stages followed by maize biomass and GY at the harvesting time. Through a weekly/biweekly airborne flight campaign, a total of 19 mosaics were acquired between both fields with a micro-hyperspectral Vis-NIR imaging sensor ranging from 400 to 850 nanometres (nm) at different crop growth stages. The PROSAIL model was calibrated and validated for retrieving maize LAI by simulating maize canopy spectral reflectance based on crop-specific parameters. The model was used to retrieve LAI from both fields and to subsequently estimate maize biomass and GY. Additionally, different vegetation indices were calculated from the aerial images to also estimate maize yield and compare the indices with PROSAIL based estimations. The PROSAIL validation to retrieve LAI from hyperspectral imagery showed a R2 value of 0.5 against ground LAI with RMSE of 0.8 m2/m2. Maize biomass and GY estimation based on NDRE showed the highest accuracies, followed by retrieved LAI, GNDVI and NDVI with R2 value of 0.81, 0.73, 0.73 and 0.65 for biomass, and 0.83, 0.69, 0.73 and 0.62 for GY estimation, respectively. Furthermore, the late vegetative growth stage at V16 was found to be the best stage for maize yield prediction for all studied indices.

In vitro degradability kinetics of Maralfalfa (Pennisetum sp.) silage withdifferent levels of inclusion and concentration of sugar cane (Saccharum officinarum) vinasse / Cinética de la degradabilidad in vitro de ensilajes de Maralfalfa (Pennisetumsp.) con diferentes niveles de inclusión y concentración de vinaza de caña(Saccharum officinarum) / Cinética da degradabilidade in vitro de ensilagem de Maralfalfa (Pennisetum sp.)com diferentes níveis de inclusão e concentração de vinhaça de canha (Saccharumofficinarum)

The use of additives promote changes in the chemical and structural characteristics of fodders during the silage process. Recent studies have shown that sugar cane vinasse can be utilized as an additive and serve as an important source of substrates which facilitate hydrolysis of the structural components of plant cell wall, increasing DM degradability. The aim of this study was to evaluate the in vitro kinetics of Maralfalfa silage degradability under different levels of inclusion (3, 6, and 9% per kg/FV) and concentration (20, 30, and 40% DM, respectively) of sugar cane vinasse. The DM degradability was determined by the in vitro gas production technique. Data were analyzed using a completely randomized design in a 3 x 3 + 1 factorial arrangement with 5 repetitions. Vinasse inclusion increased in vitro DM degradability compared to the control (59.1 vs. 51.8% after 72 h, respectively; p<0.05). Furthermore, vinasse increased the soluble fraction (A; 14.62% versus 3.68%) and the effective degradability (48.4 versus 47.4%), respectively (p<0.05). We conclude that cane vinasse enhances the in vitro degradability and the nutritional value of silage made from raw materials of low nutritional quality.

El uso de aditivos promueve cambios en las características químicas y estructurales del forraje durante el periodo de ensilado. Recientes estudios han mostrado que la vinaza de caña puede aprovecharse como aditivo y servir como una fuente importante de sustratos que faciliten la hidrólisis de los componentes estructurales de la pared celular vegetal, aumentando la degradabilidad de la MS. El objetivo del presente estudio fue evaluar la cinética de la degradabilidad in vitro del ensilaje de Maralfalfa elaborado con diferentes niveles de inclusión (3%, 6% y 9% por kg/FV) y concentración (20%, 30% y 40% de MS, respectivamente) de vinaza de caña. La degradabilidad de la MS, se determinó mediante la técnica in vitro de producción de gases. Los datos fueron analizados utilizando un diseño completamente al azar en un arreglo factorial 3 x 3 + 1 con 5 repeticiones. La inclusión de vinaza aumentó la degradabilidad in vitro de la MS con respecto al control (59,1% versus 51,8% a las 72 h, respectivamente; p<0,05). Asimismo, con la inclusión de vinaza se aumentó la fracción soluble (A; 14,62% versus 3,68%) y la degradabilidad efectiva (48,4% versus 47,4%) con respecto al control, respectivamente (p<0,05). Se concluye que la vinaza de caña es un aditivo que mejora la degradabilidad in vitro y el valor nutricional de ensilajes elaborados a partir de materias primas de baja calidad nutricional.

O uso de aditivos promove mudanças nas características químicas e estruturais da forragem durante o período de ensilagem. Recentes estudos têm mostrado que a vinhaça de canha pode ser aproveitada como aditivo e server como uma fonte importante de substratos que facilitem a hidrolise dos componentes estruturais da parede celular vegetal, aumentando a degradabilidade da matéria seca (MS). O objetivo do presente estudo foi avaliar a cinética da degradabilidade in vitro da ensilagem de Maralfalfa elaborado com diferentes níveis de inclusão (3%, 6% e 9% por kg/FV) e concentração (20%, 30% e 40% de MS, respectivamente) de vinhaça de canha. A degradabilidade da MS, determinou-se mediante a técnica in vitro de produção de gases. Os dados foram analisados utilizando um desenho inteiramente ao acaso em um desenho fatorial 3 x 3 + 1 com 5 repetições. A inclusão da vinhaça aumentou a degradabilidade in vitro da MS comparada com o controle (59,1% versus 51,8% às 72 h, respectivamente; p<0,05). Do mesmo jeito, com a inclusão da vinhaça aumentou-se a fracção solúvel (A; 14,62% versus 3,68%) e a degradabilidade efetiva (48,4% versus 47,4%) com respeito ao controle, respectivamente (p<0,05). Conclui-se que a vinhaça de canha é um aditivo que melhora a degradabilidade in vitro e o valor nutricional de ensilagem elaborado a partir de matérias primas de baixa qualidade nutricional.