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  • From: "Lawrence F. London, Jr." <venaurafarm@bellsouth.net>
  • To: permaculture <permaculture@lists.ibiblio.org>, Market Farming <marketfarming@lists.ibiblio.org>
  • Subject: [permaculture] Fwd: [SANET-MG] Improving the nutritional quality of crops
  • Date: Tue, 10 May 2011 11:44:52 -0400

-------- Original Message --------
Subject: [SANET-MG] Improving the nutritional quality of crops
Date: Tue, 10 May 2011 11:36:56 -0400
From: Joel Gruver <jgruv@HOTMAIL.COM>
To: SANET-MG@LISTS.IFAS.UFL.EDU

Hello folks,

the following abstracts are a small window into current research on improving the nutritional quality of crops.

Gregorio GB. 2002. Progress in breeding for trace minerals in staple crops. J Nutr. 132(3):500S-502S.

Abstract
Staples are not considered an important source of minerals in the diet. However, because of high staple consumption, any increase in mineral concentration might well have a significant effect on human nutrition and health. The nutritional quality of staple crops (rice, cassava, wheat, maize and beans) can be improved by breeding. Studies have shown
the potential to exploit the genetic variation in seed concentration of iron and other minerals without the general negative effect on yield of adding new traits. The relationship between yield and mineral concentration may be positive, particularly in mineral-deficient soil. Initial evaluations have shown that some crop varieties have high Fe, Zn and carotene in their edible portions. The next step for conventional breeding will be to study the genetics of trace mineral inheritance to determine the best selection technique. Initial investigations of the
genetics for high iron in rice have indicated a complex mode of inheritance, demonstrating additive and dominant gene and environmental effects. Breeding strategies have been developed based on these genetic findings. The use of biotechnological tools, such as molecular marker-assisted selection, will significantly increase the pace and prospects of success for breeding to improve the nutritional value of staple food crops.

Holtz C. 2009. The potential to improve zinc status through biofortification of staple food crops with zinc. Food Nutr Bull. 30(1 Suppl):S172-8.

Abstract
Biofortification is an agricultural strategy that aims to increase the content of select micronutrients, including zinc, in staple food crops such as rice, wheat, maize, pearl millet, and others. When consumed among zinc-deficient populations, zinc-biofortified staple foods should improve the adequacy of zinc intakes and hence reduce the risk of dietary zinc deficiency. Several conditioning factors will contribute to the potential for this strategy to meet its goal, including the additional amount of zinc that can be bred into the staple crop food, the amount of zinc that remains in the staple crop food following usual processing methods, and the bioavailability of zinc from the staple crop food in the context of the usual diet. Reduction of the phytate content of cereals with the use of agricultural techniques is a potential complementary strategy for improving the bioavailability of zinc. The feasibility of biofortification to result in a meaningful increase in the adequacy of population zinc intakes and to reduce the consequences of zinc deficiencies still needs to be determined through efficacy trials. At the program level, the ability to widely disseminate biofortified crop varieties and the willingness of farmers to adopt them will also affect the magnitude of the impact of this strategy.

Alloway BJ. 2009. Soil factors associated with zinc deficiency in crops and humans. Environ Geochem Health. 31(5):537-48.

Abstract
Zinc deficiency is the most ubiquitous micronutrient deficiency problem in world crops. Zinc is essential for both plants and animals because it is a structural constituent and regulatory co-factor in enzymes and proteins involved in many biochemical pathways. Millions of hectares of cropland are affected by Zn deficiency and approximately one-third of the human population suffers from an inadequate intake of Zn. The main soil factors affecting the availability of Zn to plants are low total Zn contents, high pH, high calcite and organic matter contents and high concentrations of Na, Ca, Mg, bicarbonate and phosphate in the soil solution or in labile forms. Maize is the most susceptible cereal crop, but wheat grown on calcareous soils and lowland rice on flooded soils are also highly prone to Zn deficiency. Zinc fertilizers are used in the prevention of Zn deficiency and in the biofortification of cereal
grains.

Broadley MR et al. 2006. Biofortification of UK food crops with selenium. Proc Nutr Soc. 65(2):169-81.

Abstract
Se is an essential element for animals. In man low dietary Se intakes are associated with health disorders including oxidative stress-related conditions, reduced fertility and immune functions and an increased risk of cancers. Although the reference nutrient intakes for adult females and males in the UK are 60 and 75 microg Se/d respectively, dietary Se
intakes in the UK have declined from >60 microg Se/d in the 1970s to 35 microg Se/d in the 1990s, with a concomitant decline in human Se status. This decline in Se intake and status has been attributed primarily to the replacement of milling wheat having high levels of grain Se and grown on high-Se soils in North America with UK-sourced wheat having low levels of grain Se and grown on low-Se soils. An immediate solution to low dietary Se intake and status is to enrich UK-grown food crops using Se fertilisers (agronomic biofortification).
Such a strategy has been adopted with success in Finland. It may also be possible to enrich food crops in the longer term by selecting or breeding crop varieties with enhanced Se-accumulation characteristics (genetic biofortification). The present paper will review the potential for biofortification of UK food crops with Se.

Johnson CC et al. 2010. Symposium on 'Geographical and geological influences on nutrition': Factors controlling the distribution of selenium in the environment and their impact on health and nutrition. Proc Nutr Soc. 69(1):119-32.

Abstract
Se is essential to human and animal health but can be toxic in excess. An interest in its geochemistry has developed alongside a greater understanding of its function in a number of health conditions. Geology exerts a strong control on the Se status of the surface environment; low-Se rock-types (0.05-0.09 mg Se/kg) make up the majority of rocks occurring at the Earth's surface, which in turn account for the generally low levels of Se in most soils. However, there are exceptions such as associations with sulfide mineralisation and in some types of sedimentary rocks (e.g. black shales) in which contents of Se can be much higher. Baseline geochemical data now enable a comparison to be made between environmental and human Se status, although a direct link is only likely to be seen if the population is dependent on the local environment for sustenance. This situation is demonstrated with an
example from the work of the British Geological Survey in the Se-deficiency belt of China. The recent fall in the daily dietary Se intake in the UK is discussed in the context of human Se status and declining use of North American wheat in bread making. Generally, US wheat has ten times more Se than UK wheat, attributed to the fact that soils from the wheat-growing belt of America are more enriched in Se to a similar order of magnitude. In agriculture effective biofortification of crops with Se-rich fertilisers must be demonstrably safe to the
environment and monitored appropriately and baseline geochemical data will enable this process to be done with confidence.

Joel Gruver
School of Agriculture
Western Illinois University
jgruv@hotmail.com





  • [permaculture] Fwd: [SANET-MG] Improving the nutritional quality of crops, Lawrence F. London, Jr., 05/10/2011

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