Response of vegetative phase growth of very early maturing rice plant to the application of liquid biosilica in paddy field

An increase in the cropping index causes the land to be cultivated more intensively and has impact on decreasing Silica content (Si) so that it is necessary to add Si to support the growth of rice plants, especially on intensive land. This research aims to study the effect of biosilica on the growth of the vegetative phase of several very early maturing rice varieties. The research was conducted from September to December 2022 in Gorontalo using a Split Plot Design. The variety as the main plot and dose of liquid biosilica as a subplot. The results showed that the treatment of Inpari 19 variety with biosilica dose of 4.5 L ha−1 had the highest number of stomata and stomata density. Individually, the Cakrabuana variety has the highest plant height, the highest number of tillers and the smallest flag leaf angle. Meanwhile, biosilica at a dose of 4.5 L ha−1 had the highest plant height and the smallest flag leaf angle. In addition, treatment of Inpari 13 and Inpari 19 varieties with biosilica dose of 3.0 L ha−1 gave the best effect on the development of blast disease intensity.


Introduction
Rice is the main food crop for the people of Indonesia, so efforts are needed to maintain its availability, one of which is to increase the cropping index by using improved variety of very early maturing rice.High-yielding varieties rice of very early maturing can be used to overcome the effects of climate anomalies, increase the rice cropping index and the productivity of rice fields [1].Silica is one of the elements that can experience a decrease in the amount of land that is intensively cultivated because there is no addition of the element to the soil and it is exacerbated by the habit of farmers not returning straw/chaff as a source of silica to the land.In addition, rice plants absorb large amounts of Si around 150-300 kg Si ha -1 [2].
The addition of organic silica (biosilica) through fertilization is expected to support plants to grow more optimally.Silica works by affecting and increasing photosynthetic activity, increasing plant resistance to pests, diseases, and lodging [3].The addition of silica combined with rice cultivation in a 1230 (2023) 012215 IOP Publishing doi:10.1088/1755-1315/1230/1/012215 2 jajar legowo system could improve the parameters of 1000 seed weight, number of tillers, plant height, and productivity [4,5].The application of liquid biosilica significantly increased rice productivity by 1.08 t ha -1 during the dry season and 1.92 t ha -1 during the rainy season, the application of 3 L ha -1 of liquid silica fertilizer increased 21.3% wet grain yield, and the 3 l ha -1 fertilizer dose indicated the highest of wet grain yield per plant [6][7][8].Therefore, it is necessary to conduct aresearch to study the effect of liquid biosilica on the growth of the vegetative phase of several very early maturing rice varieties.

Material and method
The research was carried out in September -December 2022 which took place in Dutohe Barat village, Kabila sub-district, Bone Bolango district, Gorontalo province using materials namely rice seeds of the Cakrabuana, Inpari 13 and Inpari 19 varieties, liquid biosilica (the levels of SiO2 ± 10% and K2O ± 8%) [9], Urea fertilizer, NPK fertilizer, pesticides, clear nail polish, cellophane tape.The tools used are a soil drill, land preparation tools, ticks (caplak), protractor, camera, tape measure, ruler, sprayer, microscope, plastic samples, and object glass.This study used a SplitPlot Design (SPD) where the variety (V) as the main plot consisted of three treatment levels, the Cakrabuana variety (v1), the Inpari 13 variety (v2) and the Inpari 19 variety (v3).As a subplot, the dose of liquid biosilica (D) which consisted of four treatment levels, namely without biosilica as a control (d1), biosilica 1.5 L ha -1 (d2), biosilica 3.0 L ha -1 (d3) and biosilica 4.5 L ha -1 (d4) with 3 replications for each treatment so that there were 36 experimental plots with a plot size of 4 m x 6 m.Seedlings were planted at 19 days after sowing using a 4:1 type 1 jajar legowo planting system with a spacing of 28 x 28 x 54 cm.The application biosilica was carried out twice at the age of 15 Days After Planting (DAP) and 30 DAP with doses according to the treatment.Observational data such as plant height, number of tillers, flag leaf angle, number of stomata, stomata density, and intensity of blast attack were collected and then analyzed for variance using the CropStat 7.2 application, and Minitab V. 25.If there is a significant effect of the treatment, then a Least Significant Difference (LSD) follow-up test is carried out at α level of α 0.05.

Agronomic instrument
The growth of rice plants in the vegetative phase can be observed through the development of plant height and the increase number of tillers which can be influenced by plant genetic factors, plant age, growing environment, and the applied treatment so that they can show different responses to each treatment.Note: The numbers in the same column followed by the same letter are not significantly different based on the LSD test at the level of α 0.05 Analysis of variance showed that the interaction of biosilica with varieties had a significant effect on the number and density of stomatal different from v3d1 both in the number of stomata and in the density of stomata.The number of stomata can increase along with the addition of silica to plants so that the rate of transpiration and absorption of CO2 for photosynthesis can increase [10].In addition, an assumed as a form of plant adaptation requirements [11].
Plants can still grow well even without the use of biosilica, but in Figure 1 same variety, there are differences in the growth of plants using biosilica and not using biosilika.Although Silica is not included in effects so that Silica is considered  2 shows that variety has no significant effect on plant height.characteristics that affect the diversity of plant appearance and these genetic characteristics will affect the ability of each plant variety to Analysis of variance showed that the interaction of biosilica with varieties had a significant effect on stomatal components.Table 1 shows that the v3d4 treatment both in the number of stomata and in the density of stomata.The number of stomata can increase along with the addition of silica to plants so that the rate of transpiration and absorption of for photosynthesis can increase [10].In addition, an increase in the number of stomata can also be adaptation to the surrounding environment as a result of Plants can still grow well even without the use of biosilica, but in Figure 1 we can see that for the same variety, there are differences in the growth of plants using biosilica and not using biosilika.
in the essential nutrients, its availability for plants can considered a beneficial element, especially in gramineae plants height, number of tillers and angels of flag leaf on the with liquid biosilica in paddy fields.has a significant effect on the number of tillers and flag height.Each variety has different genetic, morphological that affect the diversity of plant appearance and these genetic characteristics will affect to grow and develop in the same environment [13,14].Analysis of variance showed that the interaction of biosilica with varieties had a significant effect on treatment was significantly both in the number of stomata and in the density of stomata.The number of stomata can increase along with the addition of silica to plants so that the rate of transpiration and absorption of increase in the number of stomata can also be of greater evaporation we can see that for the same variety, there are differences in the growth of plants using biosilica and not using biosilika.
can provide beneficial plants such as rice [12].the treatment of very flag leaf angles but has morphological and physiological that affect the diversity of plant appearance and these genetic characteristics will affect [13,14].The numbers in the same column followed by the same letter are not significantly different based on the LSD test at the level of α 0.05 Differences in genetic traits in each variety have an influence on the growth of rice plants (Tables 1  and 2).In all observation components, Cakrabuana variety (v1) showed the best growth compared to other varieties.This cannot be separated from the genetic characteristics carried by these varieties.As we know that the Cakrabuana variety is the latest released VUB compared to Inpari 13 (v2) and Inpari 19 (v3) so that the higher number of tillers in the Cakrabuana variety is assumed to be one of the advantages possessed by these varieties compared to the previously released VUB.
The use of biosilica at different doses had a significant effect on flag leaf angle but had no significant effect on plant height and number of tillers (Table 2).The accumulation of silica in the leaves causes the leaves to become more upright, the distribution of sunlight to the canopy is more optimal and the rate of photosynthesis can increase with the increase in the number of stomata [10,15,16].Although biosilica had no significant effect on plant height and tiller count, the plant height and tiller number at a dose of 4.5 L ha -1 were higher than the control, but lower at a dose of 3.0 L ha -1 .This shows that Si as a beneficial element has an influence on the growth of rice plants but the response of plants can be different even though it is planted in the same location and environment.One of the elements needed by plants is Si and under these conditions, this Si element is available so that it has a beneficial impact on its growth.Plants are influenced by several factors including the availability of nutrients and silica nutrients which have a significant effect on the growth of rice plants, if a plant is placed in conditions containing appropriate nutrients and mineral elements, the plant will experience upward growth and become taller.The increase in plant height is a form of increasing cell division activity due to the availability of assimilates [17][18][19][20].

The incidence and severity of blast disease
Blast disease is one of the main rice plant diseases caused by the fungus Pyricularia oryzae.Observation of blast disease was carried out by observing the level of incidence and severity of the disease when the plants were 45 days after planting (DAP).In general, the observations showed various levels of disease incidence and severity (Table 3).Table 3.The observation results recapitulation of the combined effect of varietal treatments and liquid biosilica doses on the incidence and severity of blast disease of rice plants aged 45 Days After Planting (DAP).

Treatment
Incidence (%) Severity (%) 0.0 L ha -  The results showed that the highest disease incidence was obtained in the Cakrabuana variety treatment, which was significantly different from the other varieties.The incidence of blast disease on cakrabuana varieties ranged from 73.3% to 100% while the severity of blast disease ranged from 18.7% to 39.3% in all combinations with silica fertilizer application.These results are different from observations on the Inpari 13 and Inpari 19 varieties, which had a lower disease intensity of 13.3% and 20.0% for incidence and 2.0% and 5.3% for disease severity.This shows that the variety has a significant effect on the level of infection of the pathogen P. oryzae during the plant growth phase.Blast attack and its severity can be influenced by variety, age and environment [21,22].
The suppression of blast disease in both varieties is thought to occur due to genetic resistance factors that cause differences in the ability and defense mechanisms of plants.Some resistant varieties inhibit the development of pathogenic infections through the production of secondary metabolites such as phytoalexins.Phytoalexins are defense compounds that are synthesized and accumulated in plant tissues after pathogen infection, the level of plant resistance to blast disease has a positive correlation with the accumulation of the resulting phytoalexins [23][24][25].In the treatment of silica fertilizer application, administration at a dose of 3 L ha -1 showed better results than other doses.Although not significantly, the decrease in the incidence and severity of the disease in the three varieties used was consistent with the application of silica at a dose of 3 L ha -1 .Silica is beneficial for plant survival when it interacts with pathogens.Silica can also increase plant resistance to pathogens, even at low levels of Si accumulation [26].The application of Si significantly reduced the severity of blast disease in rice.The ability to reduce disease severity is due to the ability of plants to increase the production of phytoalexins-sakuratenin against P. oryzae.Phytoalexins-sakuratenin increased rapidly 2 days after silica application [27].

Conclusion
The results showed that the treatment of Inpari 19 variety with biosilica dose of 4.5 L ha -1 had the highest number of stomata and stomata density.Individually, the Cakrabuana variety has the highest plant height, the highest number of tillers and the smallest flag leaf angle.Meanwhile, biosilica at a dose of 4.5 L ha -1 had the highest plant height and the smallest flag leaf angle.In addition, treatment of Inpari 13 and Inpari 19 varieties with biosilica dose of 3.0 L ha -1 gave the best effect on the development of blast disease intensity.

Figure 1 .
Figure 1.Diagram of plant height, early maturing rice varieties with numbers in the same column followed by the same letter are not significantly different based on the LSD test at the level of α 0.05

Table 1 .
Response of plant growth to the interaction of very early maturing rice varieties with liquid biosilica in paddy fields.

Table 2 .
Response of plant growth biosilica.
in the vegetative phase to varietal treatments