The Diversity of Local Rice Varieties with Specific West Sumatra Flavor Based on Agronomic Characteristics and Yield Components

Unlike in other provinces in Indonesia, West Sumatran people prefer a specific nonsticky or pera-flavor of rice. The availability of pera-flavor rice varieties is very limited. Because of that, local rice germplasms of West Sumatra can be alternative to overcome the variety’s limitation. The research aimed to determine the diversity of West Sumatra’s local lowland rice varieties with specific preferences of West Sumatra’s people based on their agronomic characteristics and yield components. The research was conducted in farmers’ field at Air Tajun village in Lubuk Alung district and Toboh Gadang Barat village in Sintuk Toboh Gadang district, Padang Pariaman Regency, West Sumatra Province, Indonesia, from April to June 2018. A randomized complete block design with six treatments and four replications was used in this research. The treatments consisted of six of West Sumatra’s local rice varieties, i.e. Putiah Papanai, Lubuak Nyarai, Cantik Manih, Kuriak Putiah, Randah Kuning and Padi Merah. Observations were made on their agronomic characteristics and yield components. Data were analyzed using analysis of variance followed by LSD test at a 5% significance level. Results showed that the Putiah Papanai variety had relatively more productive tillers with an average of 20.8 stems and higher productivity (7.28 tons/ha) compared to other varieties.


Introduction
West Sumatra's rice production in 2020 reached 1,387,269.29 tonnes with a productivity of 4.69 tonnes/ha and harvested area of 295,664.47 ha (BPS, 2021).According to Susenas (2017), the rice consumption of West Sumatran people per capita in 2018 was one of the highest in Indonesia, reaching 109.7 kg per capita per year.West Sumatran people prefer nonsticky rice or 'pera' rice, which is different from Indonesian people in other areas who prefer the fluffier texture.The diversity of rice agroecosystems and specific consumer preferences have not been supported by a wide and sustainable variety of new superior rice varieties to anticipate and solve problems in the field, such as plant pests.
Limited choice of superior rice varieties suitable with field conditions and West Sumatra 'pera' preferences cause the increase of local varieties cultivation that have adapted for a long time to local agroecosystems.This study aims to determine the diversity of lowland rice germplasm of local varieties IOP Publishing doi:10.1088/1755-1315/1306/1/012008 2 in West Sumatra as a choice to overcome the limitations of West Sumatran 'pera' specific preferences based on agronomic characteristics and yield components.

Materials And Methods
The research was conducted in April-June 2018 on farmers' rice fields in Air Tajun Village, Lubuk Alung District, and Toboh Gadang Barat Village in Sintuk Toboh Gadang District, Padang Pariaman.has a height of ± 250 mdpl.The materials used were six local varieties of lowland rice (Lubuk Nyarai, Kuriak Putiah, Cantik Manis, Putiah Papanai, Randah Kuning, dan Padi Merah), rice production inputs, measurement tape, and stationery.A randomized block design (RBD) with four replications was used in this experiment.Plot size 3 m x 4 m, spacing 25 cm x 25 cm.Observations were made on agronomic characteristics (flowering age, number of productive tillers, plant height) and yield components (number of grains per panicle, number of pithy grains per panicle, weight of 1000 grains, rice size, yield).Data were analyzed using analysis of variance (STAR) followed by the LSD test at the 5% significant level.

Diversity of Agronomic Characteristics 3.1.1. Flowering Age.
The observation results of flowering age and harvest maturity on the adaptation test of several local rice varieties are presented in Table 1.The results showed that the average flowering and maturity of the Putiah Papanai variety were 101 days and 131 days, respectively.The statistical results showed that the four varieties; Randah Kuning, Padi Merah, Lubuk Nyarai, and Cantik Manis have very significant differences in the flowering and maturity ages, which were 8-16 days and 9-16 days, respectively, shorter than Putiah Papanai.At the same time, Kuriek Putiah variety was not significantly different from the Putiah Papanai variety.The numbers in each column followed by the same lowercase letter are not significant according to LSD at the 5% level The difference between flowering and maturity age normally ranges from 28 -35 days, but 29-30 days in the study.During this experiment, the perfect light intensity and relatively high daily temperature caused the difference between flowering age and shortened maturity age.Previous research on the highland environment showed the height difference between flowering and maturity could reach 40 days (Zen et al., 1988).

Number of Productive Tillers.
The observation results of the number of productive tillers of Putiah Papanai variety along with five other local varieties at two locations are presented in Table 2.The numbers in each column followed by the same lowercase letter are not significant according to LSD at the 5% level The plant adaptation results showed that the Putiah Papanai variety had relatively more productive tillers at the two locations, respectively, 20.9 stems in Air Tajun and 20.8 stems in Toboh, with an average of 20.8 stems compared to the other five varieties.Randah Kuning, Padi Merah, and Lubuk Nyarai were significant to very significantly different in statistics with fewer productive tillers, while Kuriek Putiah and Cantik Manis variety were not significantly different compared to Putiah Papanai variety.Referring to the grouping of rice tillers, the Putiah Papanai variety has a lot of tillers (20-25 stems/hills), while the other five varieties have 15.2-18.6 tillers, including the medium tiller group (Zen et al., 2002).Widyastuti et al. (2015) stated that the number of productive tillers is one yield component that contributes directly to rice yields.

Plant Height.
The observation results of plant height diversity of several of West Sumatra's local lowland rice varieties are presented in Table 3.The results showed that the Putiah Papanai variety had a plant height of 146.8 cm in Air Tajun and 148.5 cm in Toboh, with an average of 147.6 cm.The results of the combined analysis of the two locations showed that the Putiah Papani variety was significantly different, which was 42 cm -56 cm taller than the other five local varieties.The numbers in each column followed by the same lowercase letter are not significant according to LSD at the 5% level

Plant height ( c m )
Referring to the standard criteria of IRRI (1996), the Putiah Papanai variety is a group of plants with tall posture while the other five groups are moderate.Altitude will determine the air temperature, sunlight, and humidity that affect the plant growth; in this case, the plant's age will increase while the plant's posture will be shorter with increasing the elevation of the environment.The appearance of the relatively large and strong stems of the Putiah Papanai variety will cause this variety to be resistant to falling, especially if KCl fertilizer is given in the fertilizer recommendation.

Diversity of Yield Component 3.2.1. Number of Grain Per Panicle.
The observation results of the diversity of the number of grains per panicle of several West Sumatra's local lowland rice varieties are presented in Table 4.The results of the number of grains per panicle diversity showed that the Putiah Papanai variety was very significantly different; the number of grains per panicle was 17 -23 grains compared to the other five varieties, such as Randah Kuning (20 grains), Padi Merah (23 grains), Lubuk Nyarai (19 grains), Kuriek Putih (20 grains), and Cantik Manis (17 grains).Environmental differences have the opportunity for the emergence of different potentials in the same plant character, in which at the location of Air Tajun Lubuk Alung, the Cantik Manis variety was not significantly different from Putiah Papanai.While at the Toboh location, the Lubuk Nyarai variety was not significantly different from the Putiah Papanai variety.This is in accordance with Sutoro et al. (2015) that said this difference is caused by the genetic potential in the favorable environment.The numbers in each column followed by the same lowercase letter are not significant according to LSD at the 5% level

Number of Pithy Grain per Panicle (Grains).
The observation results of the diversity of pithy grains per panicle of several West Sumatra's local lowland rice varieties are presented in Table 5.The average appearance of the pithy grains per panicle of the six varieties at both locations ranged from 126 to 148 grains.The combined analysis results showed that the Putiah Papanai was a higher difference in the number of pithy grains, i.e., 14 -24 grains per panicle, compared to the other five varieties, namely Randah Kuning (22 grains), Padi Merah (16 grains), Lubuk Nyarai (17 grains), Kuriek Putih (12 grains) and Cantik Manis (12 grains).In this case, there was a difference in the number of pithy grains per panicle between tested varieties.Referring to Sutoro et al. (2015) that there is a weak positive correlation between the number of primary panicles and the weight of filled grains.Furthermore, Sutaryo (2014) states that the number of filled grains per panicle directly affects grain yield and almost always indirectly affects the relationship between grain yield and its yield component.The average percentage of pithy grains from the six tested varieties ranged from 78.9% -84.2%.There was no correlation between the number of panicle grains and the percentage of pithy grains.In this case, the highest number of grains per panicle was found on the Putiah Papanai variety, which was not significantly different from the other five varieties.The number of grains per panicle of Putiah Papanai variety is still in the medium category, so the appearance of the pithy grain percentage is still high, which is different from the new type of rice variety Famawati, which has the number of grains per panicle >250 grains and tends to have a relatively low percentage of pithy grain.
The numbers in each column followed by the same lowercase letter are not significant according to LSD at the 5% level Weight of 1000 Grains and Grain Size.The results of the diversity of 1,000 grains weights and grain sizes of several West Sumatra's local lowland rice varieties are presented in Table 6.The average appearance of 1,000 grains weights of the six varieties at both locations ranged from 18.3-25.9grams.The Randah Kuning (25.9 g) and Padi Merah (24.9 g) varieties had the highest weight of 1,000 grains and were significantly higher than the Putiah Papanai variety.The other three varieties; Lubuak Nyarai, Kuriek Putiah, and Cantik Manis were slightly significantly different than Putiah Papanai.Based on the preferences varieties of West Sumatra's consumers, its have a medium shape, not too long, and not too short in grain size, and this is reflected in the weight of 1,000 grains and the grain shape.The grain shape is reflected in the grain length and width ratio.Putiah Papanai variety is categorized as a 'slim' grain.The Cisokan and IR 42 varieties, which consumers favor, have relatively the same 1000-grain weight as the Putiah Papanai variety.The numbers in each column followed by the same lowercase letter are not significant according to LSD at the 5% level According to Rusdi and Bahar (1999), there is a correlation between the yield and weight of 1,000 grains, grain per panicle number, and filled grain per panicle number.This condition might occur if the weight of 1,000 heavy grains is followed by a large number of pithy grains.On the other hand, a relatively moderate of 1,000 grains weight still has a high yielding potential if the number of filled grains per panicle is large, as well on this Putiah Papanai variety.

Yield (Dry Milled Rice).
The performance of the yield diversity of several West Sumatra's local rice varieties is presented in Table 7.There are differences in the yield of each variety, both between locations and within the same location, Putiah Papanai variety gave the highest average yield (7.28 t/ha) and was significantly higher than the other five varieties, both from each location and the combined analysis of the two locations.The highest yield was found in Air Tajun (7.53 t/ha).According to Singh et al. (2013), the differences in grain yield are influenced by genetic potential.It was high compared to IR 42 variety planted in the surrounding experimental area, which produced 6.50 t/ha.The high yield of this Putiah Papanai variety was supported by the components of productive tillers and the high number of pithy grains.Yoshida (1981) stated that the yield is determined by yield components such as productive tillers and the percentage of pithy grains.Furthermore, Rusdi and Bahar (1999) also stated that the real yield is contributed by the weight of 1,000 grains character and pithy grains in upland rice.The numbers in each column followed by the same lowercase letter are not significant according to LSD at the 5% level The high productivity of the Putiah Papanai variety in the field causes farmers to tend to plant it more than other local varieties.Moreover, the other alternative varieties are only limited to IR42, Cisokan, and Batang Piaman.Those three high-yielding varieties are susceptible to tungro and blast disease in Padang Pariaman.New superior varieties are Inpari 12, Inpari 17 and Inpari 21, with a texture of brown rice (amylose> 25%).Inpari 12 was attacked by brown planthopper, while the taste of Inpari 21 rice is a bit soft to fluffier, and Inpari 17 is susceptible to blast disease, so those three varieties were less preferred by West Sumatra's consumers.

Conclusion
The diversity of local rice varieties with a specific taste of West Sumatran people based on agronomic characteristics and yield components was obtained.Putiah Papanai variety has relatively more productive tillers (20.8 stems on average) and high productivity (7.28 ton/ha), an alternative of a local rice variety to be developed further in West Sumatra.

Acknowledgement
The author thanks the Food Crops, Horticulture and Plantations Department in Padang Pariaman District, SDG teams and all those who have assisted in this writing.

Table 1 .
Variety of flowering and maturity age of several local lowland rice varieties in West Sumatra, planting season of 2018.

Table 2 .
Diversity in the number of productive tillers of several local lowland rice varieties in West Sumatra, planting season of 2018.

Table 3 .
Plant height diversity of several local lowland rice varieties in West Sumatra, planting season of 2018.

Table 4 .
The diversity of the number of grains per panicle of several local lowland rice varieties in West Sumatra, planting season of 2018.

Table 5 .
Diversity of pithy grains per panicle of several local lowland rice varieties in West Sumatra, planting season of 2018.

Table 6 .
Diversity of 1,000 grains weights and grain sizes of several local lowland rice varieties in West Sumatra, planting season of 2018.

Table 7 .
Performance of the yield diversity of several local rice varieties in West Sumatra, planting season of 2018.