Recent Advances In Flower And Fruit Development In Perennial Plants

The onset of flowering is an important step during the lifetime of a flowering plant. During the past two decades, there has been enormous progress in our understanding of how internal and external (environmental) cues control the transition to reproductive growth in plants. Many flowering time regulators have been identified from the model plant Arabidopsis thaliana. Most of them are assembled in regulatory pathways, which converge to central integrators which trigger the transition of the vegetative into an inflorescence meristem. For crop cultivation, the time of flowering is of upmost importance, because it determines yield. Phenotypic variation for this trait is largely controlled by genes, which were often modified during domestication or crop improvement. Understanding the genetic basis of flowering time regulation offers new opportunities for selection in plant breeding and for genome editing and genetic modification of crop species.

Nitrogen (N) is a mineral nutrient that is essential for the normal growth and development of plants that is required in the highest quantity. It is an element of nucleic acids, proteins, and photosynthetic metabolites, therefore crucial for crop growth and metabolic processes. Recently, it was estimated that N fertilizers could meet the 48% demand of the world’s population. However, overuse and misuse of N fertilizers raised environmental concerns associated with N losses by nitrous oxide (N2O) emissions, ammonia (NH3) volatilization, and nitrate (NO3−) leaching. For instance, NH3 is a pollutant in the atmosphere, N2O is a greenhouse gas that has a warming potential 298 times higher than CO2 and contributes to ozone depletion, and NO3− causes eutrophication of water bodies. Agricultural practices account for about 90% of NH3 and 70% of N2O anthropogenic emissions worldwide. The efficient use of N chemical fertilizers can be attained through cultural and agronomic practices. Nitrogen use efficiency (NUE) is an important trait that has been studied for decades in different crops. The grain production or economic return from the per unit supply of N fertilizer simply explained the NUE. Several definitions were suggested by different researchers. NUE can be defined as the product of N uptake efficiency (NUpE) and N utilization efficiency (NUtE). An increase in NUE increases the yield, biomass, quality, and quantity of crops. N is generally applied as chemical fertilizer to the soil, whereas a small amount is added to some crops like grain legumes through the fixation process. On the other hand, crop plants take N through the root system in the form of nitrate or ammonium which is thereby used in different metabolic processes. A number of studies have been conducted to increase the NUE in different crops and it has been indicated that NUE can be improved by agronomic, physiological, biochemical, breeding as well as molecular approaches. Nitrogen is the main limiting nutrient after carbon, hydrogen, and oxygen for the photosynthetic process, phyto-hormonal and proteomic changes, and the growth-development of plants to complete their lifecycle. Excessive and inefficient use of N fertilizer results in enhanced crop production costs and atmospheric pollution. Atmospheric nitrogen (71%) in the molecular form is not available for the plants. For the world's sustainable food production and atmospheric benefits, there is an urgent need to upgrade nitrogen use efficiency in the agricultural farming system. Nitrogen losses are too high, due to excess amount, low plant population, poor application methods, etc., which can go up to 70% of total available nitrogen. These losses can be minimized up to 15–30% by adopting improved agronomic approaches such as optimal dosage of nitrogen, application of N by using canopy sensors, maintaining plant population, drip fertigation, and legume-based intercropping. Therefore, the major concern of modern days is to save economic resources without sacrificing farm yield as well as the safety of the global environment, i.e. greenhouse gas emissions, ammonium volatilization, and nitrate leaching.

This is a solitary attempt to streamline all the possible information related to citrus nutrition, with emphasis on diagnosis and management of nutrient constraints, employing a variety of state-of-art techniques evolved globally over the years . While doing so care has been taken to include peripheral disciplines so that the discussion becomes more lively and authoritative. An entire array of exclusive subjects has been nicely portrayed with the help of latest data and photographs.

The onset of flowering is an important step during the lifetime of a flowering plant. During the past two decades, there has been enormous progress in our understanding of how internal and external (environmental) cues control the transition to reproductive growth in plants. Many flowering time regulators have been identified from the model plant Arabidopsis thaliana. Most of them are assembled in regulatory pathways, which converge to central integrators which trigger the transition of the vegetative into an inflorescence meristem. For crop cultivation, the time of flowering is of upmost importance, because it determines yield. Phenotypic variation for this trait is largely controlled by genes, which were often modified during domestication or crop improvement. Understanding the genetic basis of flowering time regulation offers new opportunities for selection in plant breeding and for genome editing and genetic modification of crop species.

Fruits play a substantial role in the human diet as a source of vitamins, minerals, dietary fiber and a wide range of molecules relevant to health promotion and disease prevention. The characterization of genes involved in the accumulation of these molecules during fruit development and ripening, and in the overall plant’s response to the environment, constitutes a fundamental step for improving yield- and quality-related traits, and for predicting this crop’s behavior in the field. This is certainly the case for grapevine (Vitis vinifera L.), one of the most largely cultivated fruit crops in the world. The cultivation of this species is facing challenging scenarios driven by climate change – including increases in atmospheric carbon dioxide (CO2), solar radiation, and earth surface temperature, and decreases of water and nutrient availability. All these events will potentially affect the grapevine phenology, physiology, and metabolism in many growing regions and ultimately affect the quality of their fruits and of the most important derived product, the wine. The sequencing of the grapevine genome has given rise to a new era, characterized by the generation of large-scale data that requires complex computational analyses. Numerous transcriptomic and metabolomic studies have been performed in the past fifteen years, providing insights into the gene circuits that control the accumulation of all sorts of metabolites in grapevines. From now on, the integration of two or more ‘omics’ will allow depicting gene-transcript-metabolite networks from a more holistic (i.e. systems) perspective. This eBook attempts to support this new direction, by gathering innovative studies that assess the impact of genotypes, the environment, and agronomical practices on fruits at the ‘ome’-scale. The works hereby collected are part of a Research Topic covering the use of ‘omics’-driven strategies to understand how environmental factors and agronomical practices – including microclimate modification (e.g. sunlight incidence or temperature), water availability and irrigation, and postharvest management – affect fruit development and composition. These studies report well-settled transcriptomic and metabolomic methods, in addition to newly-developed techniques addressing proteome profiles, genome methylation landscapes and ionomic signatures, some of which attempt to tackle the influence of terroir, i.e. the synergic effect of (micro)climate, soil composition, grape genotype, and vineyard practices. A few reviews and opinions are included that focus on the advantages of applying network theory in grapevine research. Studies on vegetative organs in their relation to fruit development and on fruit-derived cell cultures are also considered.

In the recent years, the need to increase food production to meet the demands of rapidly increasing population from a limited land resource necessitated the use of intensive farming systems, with the inputs like narrow genetic base, high dose of fertilizers, pesticides, irrigation, monocropping, etc. which led to the development of diseases and pest. The effect of changing global climate, particularly the sharp increase in CO2 concentration, has increased the susceptibility of plants to pathogens and pests. Because of the chemicalization of agriculture, the age-old eco-friendly pest management practices like sanitation, crop rotation, mixed cropping, adjustment of date of planting, fallowing, summer ploughing, green manuring, composting, etc. are not being practiced, affecting the crops adversely. This has encouraged researchers to look for eco-friendly and novel approaches for pest management. The information on recent advances in crop protection (involving bacteria, fungi, nematodes, insects, mites and weeds) is scattered. The book delves upon the most latest developments in crop protection such as avermectins, bacteriophages, biofumigation, biotechnological approaches; bio-priming of seeds; disguising the leaf surface; use of non-pathogenic strains, plant defense activators, plant growth promoting rhizobacteria, pathogenesis-related proteins, strobilurin fungicides, RNA interference, and variety of mixtures/cultivar mixtures/multilines; soil solarization; biointensive integrated pest management; among several others (fusion protein-based biopesticides, seed mat technology and environmental methods). This book is a ready reference for students, policy-makers, scientists, researchers and extension workers.