Evaluation performance of irrigation local rice from South Tapanuli

Using new high-yielding varieties has led to increased production and availability of food, especially rice, in Indonesia. Even though it has high productivity, the popularity of consumers looking for local rice is still very high because of its taste. Apart from being long-aged, the ability of rice to only grow in specific environments causes farmers to avoid planting local rice. This research aims to evaluate the performance of irrigated rice from South Tapanuli. The research was carried out from May to August 2023 in the experimental field in Padang City, West Sumatra. Based on research results, the height of local plants is higher than the national superior varieties. Even though they have good agronomic performance, the results observed are that the generative characters of national superior varieties are better than local varieties. It was likely due to local varieties still adapting to the environment and pests and diseases to complete the life cycle.


Introduction
The use of various new superior varieties really helps farmers and the government in the food selfsufficiency program, especially rice.Based on CAS data, rice production in 2022 increased by 0.59% compared to 2021 [1].Based on data from the Ministry of Agriculture, several new national superior varieties that farmers widely use are Ciherang, IR-64, and Mekongga [2].The reason why farmers use this variety is because of its delicious taste, which many consumers like, productivity reaches 5.2 tons/ha, and it has a relatively short lifespan.The shorter the rice harvest period, the more farmers can plant rice 3-4 times in one year.The harvest period is a consideration for farmers to prefer new national superior varieties over local varieties.Local varieties that are not used will experience extinction if they are not stored and managed properly.
Good management of local varieties can support sustainable agricultural system programs as one of the primary genetic materials in plant breeding.Local varieties usually have adapted to the environment to have more specific genes to resist pests and diseases.The local variety Hawara Bunar from South Sumatra shows a higher value in weight of filled grains per clump (g) character compared to IR64 when planted in aluminum-stressed areas in Lampung [3].This research aims to evaluate the performance of irrigated rice from South Tapanuli as a source of plant breeding.It is hoped that the local varieties used will be candidate parents for producing highly productive plants resistant to pests and diseases.The research was conducted using randomized complete block design with three replicates.Before transplanting, the seeds were germinated in the seedbed.Rice was transplanted at 21 days after sowing (DAS), or the seed height about 20 cm.The transplanted plants were grown in 2 x 2 m plots, with spacing of 25 x 25 cm.Fertilization was carried out three times, with total doses of Urea 300 kg/ha, phosphorus (SP-36) 100 kg/ha, and potassium (KCl) 100 kg/ha.The sample plants were observed for agronomic characters consisting of plant height (PH (cm)), days of flowering (FD), number of total tillers (TT), number of productive tillers (PT), panicle length (PL), total grains per panicle (TG) and weight of 100 grains (WG).The data were analyzed using analysis of variance (F-test) for testing the genotypes effect.If F-test is significant, the analysis was continued with the Duncan Multiple Range Test (DMRT).Comparisons between the national superior varieties and local varieties were carred out by orthogonal contrast testing.

Results and discussion
Rice planting is carried out in rice fields.There were no problems related to plant nutrition.The loss of several harvest components was due to pest attacks.The pests that dominate in the vegetative phase are snails (Pomacea speciosa) and grasshoppers (Oxya serville).Meanwhile, during the generative phase, there are grasshoppers (Phaleoba fumosa) and birds (Passer montanus).According to Mey [4], Bird damage attacks usually occur more often in the dry season than in the wet season.Besides the seasons, bird migration times also cause more significant damage to rice fields.The most vulnerable bird attacks usually occur during the milky phase until the ripening phase.This causes the rice to have long panicles, but it has few grains when harvested.This will cause the harvest to be less than the potential productivity of the rice.
Based on Table 1, Sipoku Pandan has a panicle length that is no different from the IR64 variety (24 cm), but it only has a total of 106 grains per panicle compared to IR64 variety has total of granss per panicle 210.The number of total grains was thought to be due to the Sipoku Pandan genotype still being adapted to the environment and also having little aromas that can attract pests so that grasshoppers and birds attack harvest components.One way to control bird pests is to install nets when the rice has entered the grain-filling phase.Installing nest is in accordance with one method of controlling bird pests, according to Echo [4].
According to SES IRRI [5], plant heigh on rice are categorized into 3 groups, such as short (< 110 cm), intermediate (110 -130 cm) and tall (>130 cm).According to [6], conventional plant cultivation, especially Gramineae plants, usually has relatively high plant height.Based on Table 2, there are very significant differences between national superior varieties and local varieties.The local variety (Siporang) has a high plant height (216.13 cm) and is significantly different from Sintanur (131 cm), which is also classified as a tall rice group (Table 1) from national varieties.According to Liu et.al. [7] plant height influence on plant architecture, plant height also influences plant resistance to pests, diseases and abiotic stress.In rice, plants belonging to the tall group are susceptible to falling, especially during the rainy season.Plants classified as intermediate usually have a good appearance and produce much grain compared to tall or dwarf plants.Note: PH = plant height (cm); TT = total tiller per plant; PT = number of productive tillers; PL = panicle length; TG = total grains per panicle; WG = weight of 100 grains.** = significant at P < 0.01; * = significant at P < 0.05; ns = not significant.The same alphabetic behind the numbers showed not significant according Duncan's Multiple Range Test at α = 0.05 The character of plant height is usually more influenced by hormones and plant genetic factors.This day's research aims to improve plants, which usually aims to obtain plants with short groups.The plant height character is related to the efficiency of photosynthate and is used more for grain filling than for the vegetative character of the plant.Especially rice plants; plants that are too tall will usually be more susceptible to environmental stress, such as wind and floods, which cause the plants to fall more easily.Apart from that, short plants will usually be more economical in harvesting activities, especially in terms of labor requirements.Note: PH = plant height (cm); TT = total tiller per plant; PT = number of productive tillers; PL = panicle length; TG = total grains per panicle; WG = weight of 100 grains.** = significant at P < 0.01; * = significant at P < 0.05; ns = not significant.The same alphabetic behind the numbers showed not significant according Duncan's Multiple Range Test at α = 0.05.
The number of tillers directly affects the number of productive tillers on rice plants.Based on Table 1, Sintanur has the highest total number of tillers (41.13) but is not significantly different from Sipoku (38.67),Inpari 32 (34), Sipulo (37,17), and IR64 (36.67).Meanwhile, in terms of the number of productive tillers, IR64 has a greater number of productive tillers than all varieties, although it is not significantly different from Sintanur.According to Prakash [7], the production of tillers in rice plants is related to how the plant manages nutrients in photosynthesis.Apart from requiring Nitrogen nutrients, the P nutrients are also essential in forming the total number of tillers and the number of productive tillers.The more effective the plant is in managing nutrients, the greater the number of tillers and panicles formed, which will influence rice productivity.Apart from sufficient amounts of nutrients, plant genetics also influence plant assimilation.
According to the Indonesian Center for Rice Research, the age of rice harvest can be calculated as approximately 25 to 35 days after the flowers appear.Harvest age is grouped into ultra-early (<90 days), very early (90 -104 days), early (105 -124 days), medium (125 -150 days) and deep (<150 days) [8].Based on Table 1 shows no significant difference in flowering age between national and local plant varieties.In this study, all genotypes were included in the medium group.
Based on the characteristics of panicle length (Table 1), Sintanur has the highest panicle length (28.67 cm) compared to other varieties.Even though IR64 has a shorter panicle size (24 cm) than Sintanur, the total grain per panicle of IR64 is higher than the other varieties.Meanwhile, the local variety with the longest panicle length is Sipoku Pandan (24 cm), but the total grain per panicle that can be produced is the lowest after Siporang (100).Regarding the observed weight of 100 grains, Mekongga has the highest weight (1.67 gr) compared to other varieties.Meanwhile, the highest weight of 100 grains for local varieties is Siporang (1.37 gr).
According to Laza [9], the character of the total number of tillers will influence the character of the rice harvest.Rice with long panicles usually produces a small number of tillers and a small number of productive tillers.The reception and management of sunlight for photosynthesis will be obtained more by each leaf or tiller in plants with fewer tillers than those with many tillers.Apart from the genetic ability of each rice cultivar to form tillers, environmental conditions, especially weather, influence the ability of rice to fill grains.

Conclusions and Suggestions
The agronomic characteristics of the local South Tapanuli variety have an excellent appearance like the national superior varieties.The characteristics of Siporang's yield components can even match those of the Sintanur variety.This is likely caused by local varieties still adapting to the environment and pests and diseases to complete their life cycle.Local varieties that can still grow well should be able to be cultivated even outside their natural habitat.Local varieties with good appearance can be candidates for crossing parents, primarily to obtain specific resistance traits.

Materials and methods
This study was conducted at experimental field in Padang City, West Sumatra.It was conducted during May until August 2023.Plant materials used were 9 irrigation rice genotypes, consisting of 5 local rice (Siporang, Sipoku pandan, Pulo pandan, Sipulo and Sipoku) and 4 national superior varieties (Sintanur, Inpari 32, Mekongga, and IR64).

Tabel 1 .
Agronomic characters mean of national and local varieties

Tabel 2 .
Comparison between new national superior and local varieties