3-D Modeling of Tomato Canopies Using a High-Resolution Portable Scanning Lidar for Extracting Structural Information

In the present study, an attempt was made to produce a precise 3D image of a tomato canopy using a portable high-resolution scanning lidar. The tomato canopy was scanned by the lidar from three positions surrounding it. Through the scanning, the point cloud data of the canopy were obtained and they were co-registered. Then, points corresponding to leaves were extracted and converted into polygon images. From the polygon images, leaf areas were accurately estimated with a mean absolute percent error of 4.6%. Vertical profile of leaf area density (LAD) and leaf area index (LAI) could be also estimated by summing up each leaf area derived from the polygon images. Leaf inclination angle could be also estimated from the 3-D polygon image. It was shown that leaf inclination angles had different values at each part of a leaf

Seed germination and seedling emergence of three Artemisia species (Asteraceae) inhabiting desert sand dunes in China

Abstract Artemisia ordosica, A. arenaria and A. sphaerocephala are semi-shrubs inhabiting desert sand dunes in China and often used to rehabilitate desertified areas. Improvement of dune rehabilitation success by sowing requires better understanding of the processes involved in the control of seed germination and seedling emergence in these species. Thus, (1) effects of temperature, light and osmotica (polyethylene glycol-6000) on seed germination, and (2) effects of seed burial depth in sand and irrigation regime on seedling emergence, were studied under controlled conditions. Seeds of the three species required light for germination, and the light fluence needed for germination was dependent on temperature. Seedling emergence of the three species was maximal (70-94%) for seeds sown at a depth of 2.5 mm, and decreased with increasing seed burial depth when the pots were initially and subsequently treated with 16 mm and 3 mm irrigation at 1-d intervals. However, when the pots were initially and subsequently treated with 8 mm and 3 mm irrigation at 2-d intervals, seedling emergence was almost completely suppressed due to water deficiency in sand. It is suggested that the probability of seed germination and seedling emergence of the three species in the field is very limited, because the light requirement restricts seed germination to shallow sand layers where water is lost rapidly due to evaporation. Temperature appeared to have secondary effects on seed germination, by modifying the light sensitivity of seeds

Estimating rice yield related traits and quantitative trait loci analysis under different nitrogen treatments using a simple tower-based field phenotyping system with modified single-lens reflex cameras

CIAT- Outstanding Research Publication Award (ORPA) - 2017Application of field based high-throughput phenotyping (FB-HTP) methods for monitoring plant performance in real field conditions has a high potential to accelerate the breeding process. In this paper, we discuss the use of a simple tower based remote sensing platform using modified single-lens reflex cameras for phenotyping yield traits in rice under different nitrogen (N) treatments over three years. This tower based phenotyping platform has the advantages of simplicity, ease and stability in terms of introduction, maintenance and continual operation under field conditions. Out of six phenological stages of rice analyzed, the flowering stage was the most useful in the estimation of yield performance under field conditions. We found a high correlation between several vegetation indices (simple ratio (SR), normalized difference vegetation index (NDVI), transformed vegetation index (TVI), corrected transformed vegetation index (CTVI), soil-adjusted vegetation index (SAVI) and modified soil-adjusted vegetation index (MSAVI)) and multiple yield traits (panicle number, grain weight and shoot biomass) across a three trials. Among all of the indices studied, SR exhibited the best performance in regards to the estimation of grain weight (R2 = 0.80). Under our tower-based field phenotyping system (TBFPS), we identified quantitative trait loci (QTL) for yield related traits using a mapping population of chromosome segment substitution lines (CSSLs) and a single nucleotide polymorphism data set. Our findings suggest the TBFPS can be useful for the estimation of yield performance during early crop development. This can be a major opportunity for rice breeders whom desire high throughput phenotypic selection for yield performance traits