Comparative assessment of einkorn and emmer wheat phenomes: III. Phenology

Abstract

In-depth information on plant phenology of einkorn (Triticum monococcum L. subsp. monococcum) and emmer, (Triticum turgidum subsp. dicoccun (Schrank) Thell) germplasm is indispensable for better utilization of their available genetic resources as underutilized crops, especially under abiotic stress. Whereas; optimization of their phenology is one of the most effective strategies to achieve this goal as it is a key factor for crop adaptation under abiotic stress. The objectives of this study were to integrate quantitative phenotyping methods to describe and explain phenotypic and genotypic differences or similarities in phenological stages within vegetative and reproductive growth phases between einkorn and emmer germplasm; identify combinations of discriminating traits between einkorn and emmer germplasm at successive phenological growth stages; and estimate multivariate distances between einkorn and emmer germplasm based on their geographical sources and stage of genetic improvement. The evaluated germplasm represented a wide range of geographical origins in the Fertile Crescent of West Asia, East Africa, West and East Europe, and North America. The study developed a method for accurate estimation of synchrony and duration of phenological growth stages of the diverse germplasm; and presented a ‘sliding’ scale capable of discriminating between different ‘maturity classes’ of the species on the basis of five phenology indicators, vis: growing degree days in conjunction with plant height, normalized difference vegetative index, color space coordinates, and green gradient-based canopy segmentation. Reliable relationship was established between visual scoring and color measurements of plants based on digital images at different growth stages. This relationship may become useful for research and crop management in resource-limited areas. Accurate prediction of phenological growth stages of einkorn and emmer wheat is essential, not only for ideotype development through simulation and modeling of weather and management effects, but also to help establish a cottage industry to benefit small-scale farmers, and to improve and maintain high-quality end products from these underutilized wheat genetic resources.