The growing human population and a changing environment have raised significant concern for global food security, with the current improvement rate of several important crops inadequate to meet future demand . This slow improvement rate is attributed partly to the long generation times of crop plants. Here, we present a method called 'speed breeding', which greatly shortens generation time and accelerates breeding and research programmes. Speed breeding can be used to achieve up to 6 generations per year for spring wheat (Triticum aestivum), durum wheat (T. durum), barley (Hordeum vulgare), chickpea (Cicer arietinum) and pea (Pisum sativum), and 4 generations for canola (Brassica napus), instead of 2-3 under normal glasshouse conditions. We demonstrate that speed breeding in fully enclosed, controlled-environment growth chambers can accelerate plant development for research purposes, including phenotyping of adult plant traits, mutant studies and transformation. The use of supplemental lighting in a glasshouse environment allows rapid generation cycling through single seed descent (SSD) and potential for adaptation to larger-scale crop improvement programs. Cost saving through light-emitting diode (LED) supplemental lighting is also outlined. We envisage great potential for integrating speed breeding with other modern crop breeding technologies, including high-throughput genotyping, genome editing and genomic selection, accelerating the rate of crop improvement.

The activity of surface receptors is location specific, dependent upon the dynamic membrane trafficking network and receptor-mediated endocytosis (RME). Therefore, the spatio-temporal dynamics of RME are critical to receptor function. The plasma membrane receptor flagellin sensing2 (FLS2) confers immunity against bacterial infection through perception of flagellin (flg22). Following elicitation, FLS2 is internalized into vesicles. To resolve FLS2 trafficking, we exploited quantitative confocal imaging for colocalization studies and chemical interference. FLS2 localizes to bona fide endosomes via two distinct endocytic trafficking routes depending on its activation status. FLS2 receptors constitutively recycle in a Brefeldin A (BFA)-sensitive manner, while flg22-activated receptors traffic via ARA7/Rab F2b- and ARA6/Rab F1-positive endosomes insensitive to BFA. FLS2 endocytosis required a functional Rab5 GTPase pathway as revealed by dominant-negative ARA7/Rab F2b. Flg22-induced FLS2 endosomal numbers were increased by Concanamycin A treatment but reduced by Wortmannin, indicating that activated FLS2 receptors are targeted to late endosomes. RME inhibitors Tyrphostin A23 and Endosidin 1 altered but did not block induced FLS2 endocytosis. Additional inhibitor studies imply the involvement of the actin-myosin system in FLS2 internalization and trafficking. Altogether, we report a dynamic pattern of subcellular trafficking for FLS2 and reveal a defined framework for ligand-dependent endocytosis of this receptor.

Crop production needs to increase to secure future food supplies, while reducing its impact on ecosystems. Detailed characterization of plant genome structure and genetic diversity is crucial for meeting these challenges. Advances in genome sequencing and assembly are being used to access to the large and complex genomes of crops and their wild relatives. Sequencing of wild crop relatives is identifying a wide spectrum of genetic variation, permitting the association of genetic diversity with diverse agronomic phenotypes. In combination with improved and automated phenotyping assays and functional genomic studies, genomics is providing new foundations for crop-breeding systems. In the twentieth century, famines caused by political crises, mismanagement of food production or genocide killed an estimated 70 million people and were second only to war as the greatest manmade cause of death 1 . The father of the Green Revolution, Norman Borlaug, summarized the importance of crops: "Without food, people perish, social and political organizations disintegrate, and civilizations collapse. " For thousands of years, people have dedicated considerable resources to securing food supplies; for example, grain supplies to ancient Rome were secured through an extensive network of long-distance transport, and the distribution of grain was coordinated and subsidized by the cura annonae ('care for the grain supply'), an important figure who contributed to the maintenance of political unity and power.During the past 10,000 years, a period known as the Holocene, Earth's environment has been unusually stable. This probably facilitated the domestication of crops from wild species, resulting in steadily improved yields and adaptation to new agricultural areas. The production of food is now carried out on a vast scale, with 38% of Earth's surface dedicated to agriculture 2 . This increased production is having a pervasive influence on ecosystems worldwide: nitrogen production for agriculture accounts for 1.2% of global energy consumption 3 ; photosynthesis can no longer maintain stable levels of atmospheric carbon dioxide; and food production consumes around 70% of freshwater supplies. The modelling of crop responses to increases in temperature predicts that there will be a considerable reduction in the yield of rice, an important crop around the world 4 . Climate change could also alter the dynamics of crop pathogenic agents by altering the range of vectors and by compromising the immune response of crops 5 .Crop production must therefore adapt to more variable environments and the substantial impact it has on the environment needs to be reduced. Productivity must also increase at a much greater rate than in the past to meet the needs of Earth's growing population 6 . Genetic improvements in crop performance continue to be crucial for increasing crop productivity, but current rates of improvement are unable to meet the demands of sustainability and food security 7 . Plant genomics has a central role in the improvement of crops, includi...