Though rice is the predominant source of energy and micronutrients for more than half of the world population, it does not provide enough zinc (Zn) to match human nutritional requirements. Moreover, climate change, particularly rising atmospheric carbon dioxide concentration, reduces the grain Zn concentration. Therefore, rice biofortification has been recognized as a key target to increase the grain Zn concentration to address global Zn malnutrition. Major bottlenecks for Zn biofortification in rice are identified as low Zn uptake, transport and loading into the grain; however, environmental and genetic contributions to grain Zn accumulation in rice have not been fully explored. In this review, we critically analyze the key genetic, physiological and environmental factors that determine Zn uptake, transport and utilization in rice. We also explore the genetic diversity of rice germplasm to develop new genetic tools for Zn biofortification. Lastly, we discuss the strategic use of Zn fertilizer for developing biofortified rice.

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Terminalia chebula (Aralu) is a valuable medicinal plant, which has an amazing power to combat various kinds of ailments.The plant becomes endangered due to its poor natural resurgence, unsustainable harvesting together with over exploitation. The conventional propagation of Terminalia chebula is through seeds and their germination is very low.This study was focused on morphological characterization of Terminalia chebula germplasm and to select suitable vegetative propagation method. A field survey was carried out in Galle and Matara districts, in Southern province of Sri Lanka for germplasm characterization. Ten plants were selected from each district. Information on growing environment, plant, leaf and fruit characters were collected and compared with the herbarium of Royal Botanical Garden. Data were subjected to a cluster analysis and two sample t test. In subsequent experiments, grafting, budding and air layering were practiced and they were carried out at the medicinal plant garden, Pinnaduwa, Galle. One-year old healthy rootstocks of Terminalia catappa (kottamba) and Terminalia bellerica (bulu) were used for wedge grafting and patch budding while keeping Terminalia chebula as the scion. Completely randomized design in factorial arrangement was used with 9 replicates. Air layering was carried out using two hormone types together with their three different concentrations including 500,700 and 900 ppm. Randomized complete block design was used with three replicates. Six different categories of Terminalia chebula were identified by cluster analysis. Both Terminalia catappa and Terminalia bellerica rootstocks can be used for vegetative propagation of Aralu. The highest survival percentages of 78% and 67% were recorded respectively in wedge grafted Terminalia chebula using Terminalia catappa root stock and patch budding with Terminallia bellerica. Types and concentrations of hormones used were not effective for Terminalia chebula air layering. Different categories of Aralu reported in study provide clues for its existing considerable genetic variability. Chemical compounds present in these six different categories warrant further investigation.

Evolvulus alsinoides Linn (Vishnukranthi) is a multipurpose medicinal herb used to treat various ailments in traditional Ayurveda medicine. Less availability of quality planting materials exist as a major bottleneck for its commercial scale cultivation. Therefore, a series of experiments were undertaken to evaluate the most promising media for seed and vegetative propagation of Evolvulus alsinoides. Seed viability was tested by Tetrazolium test (TZ test). Suitable seed germination media was tested using seed trays filled with eight potting mixtures in a completely randomized design with five replicates. The effect of auxin (Indole Acetic Acid (IAA) and Indole Butyric Acid (IBA) at 3000 ppm) and rooting media on soft wood and semi hardwood cuttings of Evolvulus alsinoides was tested. Data were analyzed using ANOVA with a statistical analysis system at 5% significance level, and means were separated using Duncan Multiple Range Test. TZ test exhibited the seed viability percentage as 87%. Early and significantly (P≤0.05) higher seed germination (79%) was observed in the soil: sand (1:1) nursery media. Sand was the best media to propagate stem cuttings of E. alsinoides. The highest plant height of 20.3 cm was observed with IBA treated top wood cuttings. Semi hardwood cuttings treated with IAA reported the best performance in terms of number of leaves, number of branches, shoot dry weight, root dry weight and whole plant dry weight of E. alsinoides. Therefore, seed germination in soil: sand (1:1) media and semi hardwood cuttings established in sand media treated with 3000 ppm of IAA were most suitable for propagation of E. alsinoides in mass scale. Potential farmers could easily adopt these findings for cultivation of this valuable medicinal plant.