New plant breeding technologies (NPBTs) for food security
Sustained improvement in agricultural productivity is needed to feed the growing global population. Alongside this, land for agriculture is declining as more land is used for urbanization and related developmental activities. A group of scientists argue that with careful deployment and scientifically informed regulation, new plant breeding technologies (NPBTs), such as genome editing, can contribute substantially to global food security. NPBTs may allay fears associated with GM crops. For example, recent advances in genome editing allow the alteration of endogenous genes to improve traits in crops without transferring transgenes across species boundaries. CRISPR-Cas has emerged as a major system to edit the crop genome. Because of its low cost, genome editing can also be used to improve orphan crops (those on which research is not well-funded), such as local fruits and vegetables, and staple crops, both of which can play an important role for healthy diets. While the use of foreign DNA in transgenic GM crops invites heavy regulation, the absence of transgenes in genome-edited crops could lower the costs of the regulatory procedures and thus speed up innovation, increase competition in the seed industry, and make improved seeds more affordable for farmers in developing countries. The lack of technical, regulatory, and communication mechanisms to handle transgenic GM technologies locally has contributed to their limited public acceptance and adoption. Therefore, a renewed effort and strategy is needed to enable the adoption of genome-edited crops and other NPBTs for their potential benefits. Learning from the past, the strategy should be based on transparent communication, training of researchers and other stakeholders in the innovation system, and efficient, informed regulation.
For more details, go to https://science.sciencemag.org/content/363/6434/1390/tab-pdf
‘Moonlighting’ Genes and Maize Yields
Protein ‘moonlighting’ (or gene sharing) is a phenomenon by which a protein can be enabled to perform more than one function. Globally, maize is a major staple and feed crop. From humble beginnings in Teosinte, it has been transformed into a major crop resulting from decades of selection. To meet the global challenge of food security, scientists and farmers are looking for ways to further optimize maize yields. One way of doing so is to adjust metabolic pathways. Researchers at the Cold Spring Harbor Laboratory (CSHL), USA have identified a relationship between maize yield and a genetic activity of the plant’s metabolic pathways, which has the potential to increase crop resilience and give higher yields in maize. CSHL Professor David Jackson and his team have connected the RAMOSA3 gene to branching, which can affect its yield. When a maize plant has too many branches, it will expend more energy towards making those branches, and less towards making seeds. More branches thus often mean lower or less efficient yields. Ears, or cobs, are normally not branched. But maize mutants that don’t have the RAMOSA3 gene can end up with branched ears. Jackson and his team initially hypothesized that the enzyme that RAMOSA3 encodes, called TPP, and a sugar phosphate called T6P which TPP acts on, are likely responsible for the ear-branching. Although the precise function of T6P remains “largely elusive,” the scientists believe that it has signalling properties.
Then, in a surprising twist, they found that a related gene, TPP4, also helps to control branching, but that gene’s effect was unrelated to its enzymatic activity. They wondered if the same might be true for RAMOSA3 and its own enzymatic activity. To follow up on this, they blocked only the enzyme activity associated with RAMOSA3, and not the gene itself, and got normal-looking ears of maize. This indicates that although RAMOSA3 controls the activity of the enzyme, it seems the enzyme activity is not responsible for controlling branching. Thus, the gene may be “moonlighting” with a hidden activity. The question of what that moonlighting may entail requires further research. The work reported here on the maize plant could lead to better crop yields and more efficient harvesting in other crops as well, such as rice and quinoa.
For more details, go to https://phys.org/news/2019-04-crop-yield-maize-unexpected-gene.html and Nature Plants (2019). DOI: 10.1038/s41477-019-0394-z
Enzymes to help wheat to cope with saline soils
Scientists from University of Western Australia have discovered two enzymes that explain the sensitivity of wheat plants to saline soils. These findings could lead to advances that help crops to cope with salinity. Salinity is a global agricultural issue, which can reduce yields ranging up to 25%. The researchers also report that wheat has a natural defence system that can bypass one of the sensitive enzymes, partially protecting against salt. Improved understanding of the effects of salinity on crops at a molecular level is essential for developing more tolerant wheat varieties. The bypass system identified by the researchers, called the ‘GABA shunt’, allows wheat plants to stop using one of their salt-sensitive enzymes when threatened by saline soil. However, the resistance thus provided also appears to have a limit, as it is overpowered by highly saline soils. Yet, the knowledge of how to control the GABA shunt, its timing and intensity, may be able to boost the wheat plant’s natural resistance to salt. The resulting varieties of wheat would not only reduce yield losses but would also allow farmers to reclaim land currently too saline for wheat crops.
For more details, go to https://doi.org/10.1111/nph.15713
Bird-scaring drones to provide peace for farmers
As drones have become more common and affordable, fears have arisen about their tendency to scare wildlife. Yet that very problem may have a silver lining: drones might be used to scare animals away from crops, resolving conflicts without using lethal force. In a study published in the journal Crop Protection, researchers led by Zihao Wang, an aerospace engineer at the University of Sydney, describe how they deployed an unmanned aerial vehicle (UAV) at Australian vineyards confronted by ravens and cockatoos, with a taste for grapes. This is no small matter: some vineyards have reported crop losses of up to 83 percent, and current methods of crop protection leave much to be desired.
Bird-excluding nets are cumbersome. Chemical repellents have unintended environmental consequences. Loud noise and scarecrows can work for a while, but target birds/animals soon get used to them. Poisoning or shooting crop-eating animals also provides temporary relief, but there are always more hungry critters to take their place. And death is hardly a fair punishment for eating someone else’s food.
Wang and colleagues drew upon research into the responses of birds to unfamiliar predators, by fitting an off-the-shelf hexacopter—a six-rotor UAV commonly used by hobbyists to take aerial photos—with the taxidermized body of a dead crow, plus a loudspeaker that broadcast the distress calls of several bird species. The researchers figured that any bird confronted by that airborne grotesquery would think the crow had been seized by some unknown beast.
For more, go to http://www.anthropocenemagazine.org/2019/03/drones-protect-crops/
High-oestrogen clovers affecting Australian sheep producers
A team of researchers at The University of Western Australia (UWA) are working together with farmers to tackle an issue which could have a devastating impact on Australian sheep producers. Older cultivars of subterranean clover (Trifolium subterraneum) cultivated up to the 1970s could contain high levels of the oestrogen formononetin in their green leaves. UWA Scientists report that continued exposure to high-oestrogen clover cultivars could have serious and long-term impacts for grazing sheep, including temporary or permanent infertility, depending on how long such grazing has occurred. The grazing of high-oestrogen pastures can also cause an increase in ewe mortality, uterine prolapse, difficult births, and post-natal lamb mortality.
The issue was assumed to be largely resolved with the introduction of new clover cultivars selected for low oestrogenic compounds in the 1980s. However, in a recent national survey by UWA, the old subterranean clover cultivars were still found to be common in many pastures across southern Australia. The survey reported that many sheep producers in Western Australia are not yet aware of this issue, and they may mistakenly associate poor reproductive performance of their sheep with other animal husbandry problems. Therefore, UWA has initiated an awareness programme to tackle the issue of high-oestrogen subterranean clovers again. UWA is offering a free service to Australian farmers in 2019 by mapping the occurrence of high-oestrogen subterranean clover cultivars and providing advice to farmers on how to remedy this issue, including supply of new clover cultivars with low levels of the oestrogen formononetin.
For more details, go to
Studies on the effects of climate change on crop diseases and pests
The concentration of Carbon Dioxide (CO2) in the atmosphere has risen from 280 parts per million (ppm) to 410 ppm over the past 150 years, causing a disruptive warming. How the rising CO2 levels will affect the crops and their diseases is still not clear. Devastating crop diseases suddenly emerge from obscurity—often becoming epidemic far from their place of origin.
Plants depend heavily on two substances, salicylic acid and jasmonic acid, to repel pathogens. High CO2 levels influence the production of these two acids and make the plants vulnerable to diseases. Plant biology is altered substantially by a range of environmental factors, making it difficult to predict the effects of changing climate. Higher atmospheric CO2 is shown to enhance growth of many plants, but also shifts their defences to favour some diseases over the others.
Changes in temperature and water availability also alter immune responses of plants. For example, potato and rice have lower disease incidence at higher moisture levels. High humidity, in general, favours the spread of plant diseases. Diseases, like papaya ring spot virus, thrive in higher temperatures while others, like potato cyst, are weakened. Weather change also is known to affect behaviour of insect vectors that transmit diseases. Genes that confer resistance to diseases that might become severe in the future need to be identified. Though modern crop varieties have the genes to face the challenges of the current climate, they are still vulnerable to weather changes.
Wild relatives of the modern-day crops might have genes with the potential to mitigate problems from future diseases, as they have good survival mechanisms. They are being collected, evaluated, and catalogued, but the speed and efficiency of that activity needs to improve. The International Centre for Tropical Agriculture (CIAT) reckons that about 30% of the wild relatives of modern crops are unrepresented in gene banks.
Several countries are becoming protective of their plant genetic resources. They want to have a share of the profits from the use of their resources. Rich countries must abide by the rules governing collection and utilization of plant genetic resources. Farmers in the poor countries with rich plant genetic resources are most likely to be affected by global warming. It would be ironic if that situation is worsened because of unavailability of genes from those regions to protect the world’s food crops from the effects of climate change.
For more details go to https://www.economist.com/science-and-technology/2019/04/20/understanding-how-crop-diseases-and-climate-change-interact-is-vital
India set to lose Top position in cotton cultivation to China
Climatic change, including insufficient rainfall in cotton growing regions, is reported to be responsible for the decline in cotton growing area in India. As per the latest international reports for 2018-19, India will lose its ‘top cotton producer’ tag to China, which has shown improved yields with better farming practices. The International Cotton Advisory Committee (ICAC) recently stated that India’s cotton production is expected to dip by 7 per cent due to “insufficient rainfall” in cotton growing regions, whereas production in China is expected to increase by about 1 per cent to 5.94 million tonnes. This means China will regain the ‘top producer’ title it lost to India in the 2015-16. The global data suggests India’s cotton output is projected to be at 5.98 million tonnes for the August-December period of the 2018-19 season.
According to Cotton Association of India (CAI), India’s cotton output is expected to dip to about 335 lakh bales (each of 170 kg, amounting to nearly 5.7 million tonnes) for 2018-19, its lowest since 2010-11, when it reported 332.25 lakh bales. While the yields are low, the possibility of adding new areas for cotton cultivation is limited by the pest menace. As against India’s projected cotton yield of about 485-500 kg per hectare, China’s yield hovers around 1,755 kg. Only better crop management can enhance cotton productivity, but is constrained by inadequate rainfall, as about 77% of cotton area depends entirely on rainfall.
For details, go to https://www.thehindubusinessline.com/economy/agri-business/india-set-to-lose-no-1-cotton-grower-tag-to-china/article26186624.ece
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