Development of the vegetative period under salinity stress in several upland rice varieties

As a food crop, upland rice varieties grow well on dry land and without irrigation. Upland rice itself is an environmentally friendly cultivation because it minimizes the use of chemicals and can grow without cultivation. Not only that, in superior varieties blast resistance and tolerance to Al poisoning are important properties that must be possessed. Some rice varieties also have tolerance to salinity, however, the development of rice on saline land is hampered by the availability of varieties produced by conventional breeding at the Center for Rice Crop Research. Given these problems, testing of superior rice for salinity tolerance is carried out for the development of national rice production. Salinity stress is a form of plant response that limits crop production due to the amount of dissolved salts in the soil which reduces the ability of plants to absorb water. Currently, research has started using the varieties sitabagendit, inpago 12 and inpago 13 with a combination of 4.5 dS/m, the plants are still in a moderate state. However, it still affects plant growth.


Introduction
Rice is a cereal plant that belongs to the Poaceae (Gramineae) tribe.This plant has important economic value, and is the main food for more than half of the world's population.Indonesia is one of the countries with the highest level of rice consumption in the world, which reaches 139 kg/capita/year [1].
Upland rice is a type of rice developed in Indonesia.Even though its contribution to national production is relatively small compared to lowland rice, this type of rice has the potential to be developed especially on dry land [2].A number of local Indonesian rice germplasm have also been identified as having a fairly good tolerance for salinity such as Siputih, Lahatan Jambu, Ketan Nangka, Raden Ayu, having a good tolerance for salinity [3].
Salinity itself can reduce the germination percentage and cause a state of dormancy in the seeds.Not only reducing the production of agricultural products, but also affecting the physicochemical properties of the soil which has a negative impact on the ecological balance [4].According to [5], [8] Salinity stress can inhibit plant root growth.Where salinity can reduce root weight due to cell turgor pressure caused by decreased water content.This causes the soil water potential to decrease, making it difficult for plants to absorb water in the soil [10].
[6] also stated that saline stress causes various secondary effects on growth, because it can reduce the groundwater potential which causes osmotic stress to ion imbalance in cells, especially reducing the concentration of K+, Ca2+, and NO3 -ions, as well as causing poisoning of Na+ ions and Cl -.In plant biochemical and physiological stress, it can cause an accumulation effect at the overall level so that the plant dies or there is a decrease in productivity [7][10].
The tools used in this study were meters, PH meters, hoes, analytical scales, ropes, cameras, laptops, stationery and others to support this research.

Research methods
The research will be carried out in Medan Selayang, Medan City, Medan Selayang District, Deli Serdang Regency at an altitude of 54m above sea level and will take place from October 2022 to January 2023.
Method pThis research uses a Randomized Block Design withfactor treatment consists of: Factor I : Upland Rice Varietiesthat is:

Data analysis
Research data resulting from significantly different variances will be tested using the Duncan Multiple Range Test (DMRT) at the 5% level.

Flowering age
Based on the results of observations and analysis of variance, flowering age was obtained from the variety and salinity treatment results which are presented in table 1 as follows.

Root length
Based on the results of observation and analysis of variance, root length obtained from the varietal and salinity treatment results is presented in table 2 as follows.

Root volume
Based on the results of observation and analysis of variance, the root volume obtained from the results of the variety and salinity treatments is presented in table 3 as follows.From table 3 it can be seen that the administration of salinity had a significant effect on root volume.The highest root volume was in the P2S0 treatment (Inpago 12, control treatment) with an average value of 97 ml and the lowest root volume was in the P3S3 treatment (Inpago 13 treatment 4.5 dS/m) with a mean value of 25.66 ml.

Salinity stress index
Based on the results of observations and analysis of variance, index salinity stress was obtained from the variety and salinity treatment results which are presented in tables 4 and 5 as follows.Based on tables 2 and 3, it can be seen that the results of observing the root length of upland rice in various treatment varieties at salinity produced various root lengths.The control treatment of the situbagendit variety (P1S0) had an average root length of 47.33.In the control treatment, Inpago 12 and Inpago 13 varieties (P2S0 and P3S0) had a mean of 52.00.On treatment 1.5 dS/m Root length did not differ much, the situbagendit variety (P1S1) had an average root length of 50.00.while the Inpago 12 (P2S1) variety has an average root length of 57.00 and the Inpago 13 (P3S1) variety has an average root length of 44.00.The reduction in root length can be seen significantly by looking at the treatment 3 dS/m onthe situbagendit variety (P1S2) had an average root length of 49.66.while the Inpago 12 (P2S2) variety has an average root length of 48.00 and the Inpago 13 (P3S1) variety has an average root length of 40.33.The decrease in root length continued to occur with increasing salinity dose 4.5 dS/m, at the situbagendit variety (P1S3) had an average root length of 31.33.while the Inpago 12 (P2S3) variety has an average root length of 46.00 and the Inpago 13 (P3S3) variety has an average root length of 26.00.

Conclusions
Salinity effect has a noticeable effect on reducing flowering age, root length, root volume and root wet weight.The S0 effect did not differ markedly from the S1 stress effect on the flowering age parameter.The effect of S1 and S2 did not differ markedly from root length parameters.The varieties Inpago 12 and Inpago 13 did not differ markedly in the S3 effect.The sensitivity index shows that the inpago 13 variety is the most tolerant and the situbagendit variety has the highest sensitivity.

Figure 1a .Figure 1b .
Figure 1a.The effect of four levels of salinity on the appearance of the roots of three varieties of gogo rice.

Table 1 .
Effect of salinity level on flowering age of three varieties of gogo rice with four drought factors.

Table 2 .
Effect of salinity level on root length of three varieties of gogo rice with four drought factors.
Remark: Means followed by the same letters in the same column and row are not significantly different based on DMRT test at α = 5%.

Table 3 .
Effect of salinity level on root volume of three varieties of gogo rice with four drought factors.

Table 4 .
Salinity stress index to flowering age, root length, and root volume.

Table 5 .
Salinity stress sensitivity index to flowering age, root length, and root volume.
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