Rice (Oryza sativa) breeding strategies for grain biofortification

Loading of zinc and iron in grains of different wheat genotypes in the calcareous and floodplain soils of Bangladesh

Major malnutrition in Bangladesh is zinc (Zn) and iron (Fe) deficiency as most people commonly depend on cereals, chiefly rice and wheat. The main objectives are to enhance Zn and Fe concentrations through the use of selected varieties and the application of respective fertilizers. Field experiments were conducted at Bangladesh Agricultural University (BAU) farm, Mymensingh (AEZ 9, non-calcareous soil) and at Bangladesh Institute of Nuclear Agriculture (BINA) substation, Ishwardi (AEZ 11, calcareous soil) for two consecutive wheat seasons (2014-15 and 2015-16) with 10 varieties and 15 advanced lines. Varieties BARI Gom 25, 27, 28 & 29 and breeding lines Vijay, HPYT-5, 15 & 21 and BL-1883 have been recognized as Zn-enriched wheat varieties (24-30 μg g-1). Among the genotypes, Zn further increased by 4-8 μg g-1 due to Zn fertilization. Concerning Fe-enriched wheat genotypes (24-30 μg g-1), five varieties viz. Shatabdi, Prodip, BARI Gom 25 & 28 and Sufi, and four lines such as HPYT-12, BL-1883, BL-1040 and Fery-60 have been identified. The grain Fe concentration of wheat genotypes increased when Fe was added, the increment being 6-12 μg g-1. A positive relationship between Zn and N is observed with increased protein content. The grain yield of wheat was increased by 3.8-25.7% due to Zn application over the varieties and locations but Fe addition had no effect. The result of the current study showed that a potential breeding line with appropriate fertilization can improve Zn and Fe levels in wheat grain, without incurring loss to wheat yield.

Significance and genetic control of membrane transporters to improve phytoremediation and biofortification processes

Humans frequently consume plant-based foods in their daily life. Contamination of agricultural soils by heavy metals (HMs) is a major food and nutritional security issue. The crop plants grown in HM-contaminated agricultural soil may accumulate more HMs in their edible part, further transferring into the food chain. Consumption of HM-rich crops can cause severe health issues in humans. On the other hand, the low content of the essential HM in the edible part of the crop also causes health problems. Therefore, researchers must try to reduce the non-essential HM in the edible part of the crop plants and improve the essential HMs. Phytoremediation and biofortification are the two strategies for resolving this problem. The genetic component helps to improve the efficiency of phytoremediation and biofortification processes in plants. They help eliminate HMs from soil and improve essential HM content in crop plants. The membrane transporter genes (genetic components) are critical in these two strategies. Therefore, engineering membrane transporter genes may help reduce the non-essential HM content in the edible part of crop plants. Targeted gene editing by genome editing tools like CRISPR could help plants achieve efficient phytoremediation and biofortification. This article covers gene editing's scope, application, and implication to improve the phytoremediation and biofortification processes in non-crop and crop plants.

Genotype × environment interactions for grain iron and zinc content in rice

BACKGROUND

Nutrient deficiency in humans, especially in children and lactating women, is a major concern. Increasing the micronutrient concentration in staple crops like rice is one way to overcome this. The micronutrient content in rice, especially the iron (Fe) and zinc (Zn) content, is highly variable. The identification of rice genotypes in which there are naturally high Fe and Zn concentrations across environments is an important target towards the production of biofortified rice.

RESULTS

Phenotypic correlations between grain Fe and Zn content were positive and significant in all environments but a significant negative association was observed between grain yield and grain Fe and Zn. Promising breeding lines with higher Zn or Fe content, or both, were: IR 82475-110-2-2-1-2 (Zn: 20.24-37.33 mg kg^-1 ; Fe: 7.47-14.65 mg kg^-1 ); IR 83294-66-2-2-3-2 (Zn: 22-37-41.97 mg kg^-1 ; Fe: 9.43-17.16); IR 83668-35-2-2-2 (Zn: 27.15-42.73 mg kg^-1 ; Fe: 6.01-14.71); IR 68144-2B-2-2-3-1-166 (Zn: 23.53-40.30 mg kg^-1 ; Fe: 10.53-17.80 mg kg^-1 ) and RP Bio 5478-185M7 (Zn: 22.60-40.07 mg kg^-1 ; Fe: 7.64-14.73 mg kg^-1 ). Among these, IR82475-110-2-2-1-2 (Zn: 20.24-37.33 mg kg^-1 ; Fe: 7.47-14.65 mg kg^-1 ) is also high yielding with 3.75 t ha^-1 . Kelhrie Cha (Zn: 17.76-36.45 mg kg^-1 ; Fe: 7.17-14.77 mg kg^-1 ), Dzuluorhe (Zn: 17.48-39.68 mg kg^-1 ; Fe: 7.89-19.90 mg kg^-1 ), Nedu (Zn: 18.97-43.55 mg kg^-1 Fe: 8.01-19.51 mg kg^-1 ), Kuhusoi-Ri-Sareku (Zn: 17.37-44.14 mg kg^-1 ; Fe: 8.99-14.30 mg kg^-1 ) and Mima (Zn: 17.10-45.64 mg kg^-1 ; Fe: 9.97-17.40 mg kg^-1 ) were traditional donor genotypes that possessed both high grain Fe and high Zn content.

CONCLUSION

Significant genotype × location (G × L) effects were observed in all traits except Fe. Genetic variance was significant and was considerably larger than the variance of G × L for grain Zn and Fe content traits, except grain yield. The G × L × year variance component was significant in all cases. © 2020 Society of Chemical Industry.