Search

Efficient and affordable plant phenotyping methods are an essential response to global climatic pressures. This study demonstrates the continued potential of consumer-grade photography to capture plant phenotypic traits in turfgrass and derive new calculations. Yet the effects of image corrections on individual calculations are often unreported. Turfgrass lysimeters were photographed over 8 weeks using a custom lightbox and consumer-grade camera. Subsequent imagery was analyzed for area of cover, color metrics, and sensitivity to image corrections. Findings were compared to active spectral reflectance data and previously reported measurements of visual quality, productivity, and water use. Results confirm that Red–Green–Blue imagery effectively measures plant treatment effects. Notable correlations were observed for corrected imagery, including between yellow fractional area with human visual quality ratings (r = −0.89), dark green color index with clipping productivity (r = 0.61), and an index combination term with water use (r = −0.60). The calculation of green fractional area correlated with Normalized Difference Vegetation Index (r = 0.91), and its RED reflectance spectra (r = −0.87). A new chromatic ratio correlated with Normalized Difference Red-Edge index (r = 0.90) and its Red-Edge reflectance spectra (r = −0.74), while a new calculation correlated strongest to Near-Infrared (r = 0.90). Additionally, the combined index term significantly differentiated between the treatment effects of date, mowing height, deficit irrigation, and their interactions (p < 0.001). Sensitivity and statistical analyses of typical image file formats and corrections that included JPEG, TIFF, geometric lens distortion correction, and color correction were conducted. Findings highlight the need for more standardization in image corrections and to determine the biological relevance of the new image data calculations. [ABSTRACT FROM AUTHOR]

Pearl millet [Pennisetum glaucum (L.) R. Br.] is a climate‐resilient cereal crop widely grown in arid and semiarid environments and an important crop for food, fodder, and nutritional security. This study was aimed at evaluating genetic variation(s) for drought tolerance‐related traits in a set of 29 seed (B) and 27 restorer (R) lines and identifying pearl millet inbreds for hybrid development. Field experiments were conducted in a split‐plot in randomized complete block design with three replications for 2 years. Moisture regimes (irrigated and rainfed) were kept as main plot treatments, and the genotypes were used as subplot treatments. Principal component analysis and neighbor joining clustering revealed the presence of greater genetic diversity between B and R lines. Combined analysis of variance showed significant difference(s) between the lines, treatments, and years. Genotype + genotype × environment interaction biplot indicated the significant environment and treatment effect(s) on grain yield per plant, number of seeds per plant, and 1000‐grain weight. Rank summation index based on percentage reduction and multi‐trait stability index analyses for the above three traits identified the best adapted genotypes for rainfed conditions. Based on these analyses, seven seed parents (ARCH41B, ARCH01B, ARCH13B, ARCH44B, ARCH09B, ARCH24B, and ARCH30B) and six pollinators (ARCH36R, ARCH68R, ARCH22R, ARCH63R, ARCH50R, and ARCH60R) were identified as potential parents to develop high‐yielding and drought‐tolerant pearl millet hybrids for the semiarid tropics. Core Ideas: The objective of this study was to identify potential drought‐tolerant seed and pollinator lines for pearl millet hybrid development.The Presence of greater genetic diversity between the B and R lines of pearl millet was revealed.The Genotype plus genotype × environment interaction (GGE) biplot indicated the significant environment and treatment effect(s).Seven seed parents and six pollinators were identified as potential parents to develop high‐yielding hybrids for semiarid tropics. [ABSTRACT FROM AUTHOR]

Flowering in perennial species is directed via complex signalling pathways that adjust to developmental regulations and environmental cues. Synchronized flowering in certain environments is a prerequisite to commercial seed production, and so the elucidation of the genetic architecture of flowering time in Miscanthus and switchgrass could aid breeding in these underdeveloped species. In this context, we assessed a mapping population in Miscanthus and two ecologically diverse switchgrass mapping populations over 3 years from planting. Multiple flowering time quantitative trait loci (QTL) were identified in both species. Remarkably, the most significant Miscanthus and switchgrass QTL proved to be syntenic, located on linkage groups 4 and 2, with logarithm of odds scores of 17.05 and 21.8 respectively. These QTL regions contained three flowering time transcription factors: Squamosa Promoter‐binding protein‐Like, MADS‐box SEPELLATA2 and gibberellin‐responsive bHLH137. The former is emerging as a key component of the age‐related flowering time pathway. [ABSTRACT FROM AUTHOR]

Switchgrass (Panicum virgatum L.), a warm season, C4, perennial grass, is one of the predominant grass species of the North American tall grass prairies. It is viewed as a high-potential bioenergy feedstock species because it can produce large amounts of lignocellulosic material with relatively few inputs. The objectives of this project were to develop an advanced switchgrass population and use it for the construction of genetic linkage maps and trait characterization. A three-generation, four-founder population was created and a total of 182 progeny of this advanced population were genotyped, including a mixture of self-pollinated and hybrid individuals. The female map integrated both subpopulations and covered 1629 cM of the switchgrass genome, with an average map length of 91 cM per linkage group. The male map of the hybrid progeny covered 1462 cM, with an average map length of 81 cM per linkage group. Average marker density of the female and male maps was 3.9 and 3.5 cM per marker interval, respectively. Based on the parental maps, the genome length of switchgrass was estimated to be 1776 cM and 1596 cM for the female map and male map, respectively. The proportion of the genome within 5 cM of a mapped locus was estimated to be 92% and 93% for the female map and male map, respectively. Thus, the linkage maps have covered most of the switchgrass genome. The assessment of marker transmission ratio distortion found that 26% of the genotyped markers were distorted from either 1:1 or 3:1 ratios expected for segregation of single dose markers in one or both parents, respectively. Several regions affected by transmission ratio distortion were found, with linkage groups Ib-m and VIIIa-f most affected., (Copyright © 2014 Li et al.)