Drought poses a significant threat to global food security, particularly impacting rice cultivation during the germination stage. In this study, a soil-based system that utilizes soil moisture content was used to simulate optimal and stress conditions to assess the effect of the specific seed priming protocols on germination. Eleven rice varieties, representative of indica and japonica subspecies, grown in different ecosystems and having diverse nutrient contents, were treated with water or solutions of either poly-gamma-glutamic acid (γ-PGA) or denatured γ-PGA. Collected data regarding germinability and stress indices revealed different drought sensitivity between japonica and indica subspecies and genotype-specific responses to priming. Particularly, γ-PGA improved germination of highly susceptible indica varieties whereas water soaking was more effective for the moderately sensitive japonica varieties. Integrative analyses evidenced differences between biofortified and non-biofortified rice under γ-PGA treatment, suggesting a possible correlation between γ-PGA efficacy and Zn/Fe seed content. These findings underline that priming strategies should be tailored based on genotype and therefore this factor should be always taken under consideration for future works. The current study provides relevant information for optimizing seed priming techniques to sustain the development of drought-resilient crops as a sustainable strategy to address agricultural resilience and safeguard food security amidst environmental challenges.

Rice production in the karst dryland is still low, due to soil characteristics that lack nutrient availability. Meanwhile, upland rice has received less attention, and it has not been used to its full potential. This study aimed to evaluate the effect of various combinations of inorganic fertilizers, poultry manure, and upland rice varieties on the production and economic value of karst dryland in Gunungkidul, Yogyakarta. This experiment was arranged in a factorial design, with inorganic fertilizers, poultry manure, and upland rice varieties set in a randomized block design with three replications. The first factor was a combination of inorganic and organic fertilizer rates: 72 N kg ha⁻¹ + 26 P₂O₅ kg ha⁻¹ + 25 K₂O ha⁻¹ + 3 t ha⁻¹ organic, 92 N kg ha⁻¹ + 36 P₂O₅ kg ha⁻¹ + 30 K₂O kg ha⁻¹ + 2 t ha⁻¹ organic, 112 N kg ha⁻¹ + 46 P₂O₅ kg ha⁻¹ + 35 K₂O kg ha⁻¹ + 1 t ha⁻¹ organic. The second factor is the upland varieties of Inpago 8, Inpago 10, and Inpago 12 and lowland variety Inpari 42 Agritan GSR, as checked. Based on the study, we concluded that the combination of 92 N kg ha⁻¹ + 36 P₂O₅ kg ha⁻¹ + 30 K₂O kg ha⁻¹ + 2 t ha⁻¹ poultry manure fertilizers with Inpago 8 resulted in an IDR profit of 23,586,000 ha⁻¹, and it is the most recommendable fertilizer and variety combination to be developed in the karst dryland, in consideration of land fertility and sustainability.

Susanto U, Barokah U, Hidayatullah A, Satoto, Swamy M. 2017. Yield and Zn content of biofortified rice genotypes in an Indonesian rice agro-ecosystem. Nusantara Bioscience 9: 288-294. Approximately one-third of the world's population suffer from Zn deficiency causing significant socio-economic losses as a result of stunting and compromised immune system function. One strategy to overcome the problem is by developing rice cultivars with high grain Zn content (Zn Rice) to improve dietary intake.This study reports the yield and Zn content of 22 rice genotypes developed at the International Rice Research Institute (IRRI) and the Indonesian Centre for Rice Research (ICRR).The experiment was conducted in the Cirebon district of West Java province during the 2013 wet season (2013WS). Yield and grain Zn content (using an XRF machine) were measured. Five lines demonstrated higher yield (ranging from 7.0 to 8.9 t/ha) than the check variety Ciherang (5.2 t/ha), but had similar grain Zn content to the check variety Ciherang (23.4 ppm), ranging from 19.0 to 24.8 ppm. On the other hand, seven lines had higher grain Zn content (ranging from 30.0 to 34.2 ppm) compared to Ciherang, and five of these lines had comparable yield to Ciherang. The selected lines had acceptable agronomic traits, and are suitable for further testing and utilization, in addition to providing a foundation for future improvement in the dual goals of increasing the yield and nutritional value of rice.

One of the important root traits affecting drought tolerant in rice crop is root architecture. Sufficient number of vertical and deep root growth supports for higher capability of water and nutrient intake by plant. This research aimed to evaluate drought tolerance of 60 rice genotypes based on number and proportion of vertical root growth. The experiment was managed according to randomized complete block design of three replications. A pot is representing a unit data. The experiment was conducted in ICRR screen house in Sukamandi during October to December 2016. The seeds were placed on a modified sunken sieve in pot with soil media. The sieve was separated into three zones, i.e. representing vertical, medium, and horizontal root growth. The plant was established in optimum water condition for 42 days. The results showed that 42 genotypes had comparable root architecture with IR64 Dro1 line, a line having Dro1 gene which controlled vertical root growth. Among them, Inpari21, BP16178M-1D-SKI-13-8-1, HHZ5-SKI-7-1-0Kr-JK-IND, Inpari18, Towuti, and Bahbutong (1182) had either high number of vertical root growth (more than 10 roots) as well as high proportion of the vertical root growth (more than 40%). The genotypes were suspected to have good drought tolerant due to the root architecture.

Green Super Rice Project had identified the Huanghuazhan as a high yielding rice variety which relatively adaptable to global climate change since it is stable either under optimum or limited input condition. Correlation of agronomic and leaf treats is important to determine yield, which is needed even under global climate change condition. This study aimed to dissect the correlation among agronomic and leaf traits of the lines to the yield. The lines had been imported to Indonesia and tested under irrigated condition during dry season of 2013 in ICRR experimental station in Sukamandi, Subang, West Java, Indonesia. The results showed HHZ 8- SAL12-Y2-DT1 had a higher yield (8.70-ton ha^-1) than Huanghuazhan (7.01-ton ha^-1), hence prospective for further testing. Correlation analysis, however, showed out of 21 traits being observed, only filled grain/panicle having significant correlation with yield. Leaf traits such as length, thickness, and angle of flag leaf, second, and third leaf showed insignificant correlation to yield. Some agronomic traits seem to compensate each other in supporting maximum yield capacity. Developing rice plant with high filled grain per panicle with bigger grain size without reducing productive tiller number may become the ideal ideotype for high yielding rice variety.

Drough is one of major constrain in rice production in Indonesia. Developing of rice tolerant to drought would hopefully overcome the problem. Raised bed system is a modified selection method to screen drought tolerant in rice up to generative growth phase. This research aimed to evaluate 60 various genetic background of rice genotypes using raised bed method. The trial was managed according to randomized complete block design with two replications.The materials we directly planted with planting space of 20 cm x 20 cm in row plot consisted of 10 hills each. The trial was conducted in raised bed system screening facility in ICRR experimental station in Sukamandi during August – November 2016. There were five genotypes considered as tolerant based on leaf rolling and leaf drying score. There were 15 genotypes produced filled grains, ranged from 2 to 121 grains/plant or 0.12 to 4.48 grains/panicle. The seed set was ranged from 2 to 40%. Among the producing grain genotypes, BP16146M-1D-SKI-2-13-1-3, BP14352e-2-3-30p-JK-0, and BP17280M-46D-IND considered to have better drought tolerance based on number of filled grain produced and seed set rate. Yield trial of the lines would confirm the possibility for further testing for releasing variety.