Improving nutritional quality through foliar iron application of rice grown in Northeastern Thailand

บทคัดย่อ

Iron deficiency is one of the major health problems which can overcome by consuming more iron rich foods. Enriching iron content in stable food such as rice may eventually help to supply adequate iron for human health. This study was to find the way to increase grain iron content in rice. The field experiments were done at two locations (low and high soil iron content) to ascertain the effect of foliar application of iron at different growth stages in two rice cultivars. The experiments were setup in a split-plot design. In the main plots, FeSO₄ was sprayed at different growth stages (panicle initiation, flowering, milking, and panicle initiation+ flowering+ milking, including without iron application). The sub-plot consists of two rice cultivars Khao Dawk Mali 105 (poor iron concentration 5.7 mg/kg) and Riceberry (rich iron concentration 15.5 mg/kg). The foliar spray of FeSO₄ three time at panicle initiation + flowering + milking stages resulted in tend to give highest iron concentration of brown and polished rice grain in both locations, excepted the Fe concentration in polished rice grain for KDML 105 cultivar. Riceberry produced higher iron concentration in grain than Khao Dawk Mali 105 in both locations. The brown rice iron concentration was positively correlated with polished rice iron concentration. The correlations were different for different experimental sites. The iron concentration in brown and polished rice was positively correlated when grown in low iron concentration soil, but negatively correlated when grown in high iron concentration soil. The combined application at panicle initiation + flowering + milking stages significantly increased higher grain yield than a single application at panicle initiation, flowering and milking in low soil iron concentration filed, but not in high soil iron concentration field. Khao Dawk Mali 105 produced significantly higher grain yield than Riceberry in both locations.