Agronomic Performance of IPB’s Red Chili Pepper ( Capsicum annuum L.) Lines in Different Environments in Bogor, West Java, Indonesia

Our study aims to determine the agronomic performances of the red chili pepper genotypes developed by the IPB University as compared to the existing commercial varieties. The study was conducted from June 2019 to April 2020 in the Leuwikopo and Tajur experimental fields, IPB University, Bogor, West Java, Indonesia. Leuwikopo and Tajur location differs in the soil type and environments. The experiments at Leuwikopo were conducted twice, once during the dry season, and once during the rainy season. The experiments were set up in a completely randomized block design with a single factor, i.e. sixteen red chili pepper genotypes, replicated three times in three different environments. The 11 genotypes evaluated were F8120005-141-16-35-1-3, F8120005-141-16-35-1-4, F8120005-141-16-35-7-1, F8120005-241-2-9-4- 4, F7120005-120-7-1-7-8-1-2, F6074-7-4-2-1, F4074136-2-3, F474077-1, F474035-2-1, F474035-2, F4136074-1-4; these lines were compared to five commercial chili varieties, “Laris”, “Gada” F1, “Kastilo” F1, “Anies IPB”, “Seloka IPB”. Measurements were conducted on time to harvest, fruit length, fruit diameter, weight per fruit, number of fruits per plant, fruit weight per plant, and productivity. The results showed that the curly and large red chili pepper genotypes had similar agronomic performances to the control curly variety “Laris” and “Kastilo” F1, and “Anies IPB”, “Seloka IPB”, or “Gada” F1 as control variety for the large chili. Our study demonstrated that all large and curly red chili pepper lines developed in IPB University have excellent potentials to be commercialized into superior varieties.


Introduction
Chili pepper (Capsicum annuum L.) is one of the important horticultural crops in Indonesia. The planting area of chili in 2020 was 133,729 hectares, the largest of vegetable crops in Indonesia (BPS, 2020). Chili is the main contributor to the inflation increase in the volatile foods category in Indonesia, which happened in September and October 2016 (Bank Indonesia, 2016). According to the Central Statistics Bureau (2019), the national chili productivity in 2019 was 9.10 tons per hectare, which is far below the potential productivity of 20 tons per hectare (Syukur et al., 2010). Therefore, it is important to continuously improving the genetics and production system to have higher yields (Syukur et al., 2010).
The success of a breeding program depends on the genetic resource variabilities; and genetic variability occurs through crosses between two parents. Parents of pure lines or a homozygous will produce uniform heterozygous F1 derivatives, and segregation will occur in the F2 generation (Kirk et al., 2012). According to Zecevic et al. (2011), the F2 generation is the generation that has the maximum recombination of genes, so the F2 generation is the best choice for selection in plant breeding. The chili pepper lines used in this study were developed by pedigree selection.
The chili in Indonesia is mostly consumed fresh, or as an important spice for cooking. Ideally, chili is cultivated in various regions to obtain fresh produce and to shorten the transportation time from the production area and the markets and consumers. cannot produce high yields even when an optimal environment had been provided, as plant phenotype is a result of the interaction between genetic and non-genetic factors, which is represented by the environment. The objective of our study is to determine how red chili pepper genotypes and the environment affect their growth and yield of red chili pepper genotypes developed at IPB University.

Materials and Methods
The study was conducted in June 2019 to April 2020 in three different environments: experimental field at IPB-Leuwikopo during the dry season (Leuwikopo 1) and during rainy season (Leuwikopo 2), and at Tajur experimental field. Leuwikopo has an altitude of 230 m above the sea level (asl), whereas Tajus is 320 m asl. All study areas are located in the Bogor Regency, West Java, Indonesia. Post-harvest handling was conducted at the Plant Breeding Education Laboratory of the Department of Agronomy and Horticulture, Faculty of Agriculture, IPB University.
Experiments were set up in a randomized complete block design with 16 genotypes and replicated three times. Each plot is 1 m x 5 m with a bed height of 20 cm, and a distance between beds of 50 cm. Twenty chili seedlings were planted on each plot. Soil in the plots was treated with manures and agricultural lime at the standard dosage according to the location. Basal fertilizers consist of 150 kg.ha -1 urea, 300 kg.ha -1 SP-18, and 200 kg.ha -1 KCl were applied, then the beds were covered with silver black mulch. Planting holes were made with a distance of 50 cm x 50 cm within a row, with a depth of 20 cm. Seedlings were transferred to plots 21-24 days after germination or when they had 3-4 true leaves. Harvesting was conducted when 75% of the population had reached fruit ripening. Fruits are considered ripe and ready for harvest when 70% of its structure was red in color.
Growth measurements were conducted on 10 randomly selected sample plants in each plot with reference to Descriptors for Capsicum (IPGRI, 1995): harvest age (days after sowing, DAS), fruit length (cm), fruit diameter (mm), number of fruits per plant, weight per fruit (g), fruit weight per plant (g), and productivity (t.ha -1 ), which was estimated using the following corrected equation: (Fruit weight per plant x 26670 plants.ha -1 ) x 80% of the survived plants per experimental unit)/ 1,000,000 Data were analyzed using variance analysis, followed by a combined analysis of the three environments using the PBSTAT (Plant Breeding Statistics) version 2.2. For the characters with significant effects for genotype, environment, or genotype x environment, further tests were carried out using the Tukey honest real difference test for all characters. except for productivity that used Duncan Multiple Range test.

Effect of Genotypes and Environment on Growth and Yield of Red Chili Pepper
All sixteen lines of red chili pepper vary significantly in their time to harvest, fruit size (length and diameter) and weights, number fruits per plant, and productivity (Table 1). Different growing environments had significant effects on most of the plant characters of the 16 lines, except for the fruit weight per plant and productivity. Genotype and environment interaction significantly affected all yield components (Table 1). The significant differences in the growth performance and productivity of the different lines represents high genetic diversities and significant differences in the genetic background of each line (Santos et al., 2014;Syukur et al., 2011).
The interaction between genotype and environment (G x E) significantly affected all the yield components (Table 1), demonstrating that the quantitative characteristics of the red chili pepper genotypes vary between environments. According to Sa'diyah et al. (2013), the broad phenotype variability is influenced by the genetic and environmental variabilities. Plants with different genotypes could have different phenotypes/appearances when planted in the same environmental condition (Nilahayati and Putri, 2015). The significant effect of environmental genotype interactions (G × E) for all characters indicates a differential genotype responses in the environment for Tobias Moniz Vicente, Yudiwanti Wahyu, Muhamad Syukur, Asep Setiawan these traits (Sivakumar et al., 2017). The significant interaction of genotype and environmental showed differences in the adaptability of each line (Thanki et al., 2010). Genotype and environment interaction are associated with the development of varieties that demonstrates stability of the characters when planted in different environments (Syukur et al., 2018).
The time to harvest of chili pepper lines in the three environments ranged from 80.28 to 89.98 days ( Table  2). Early harvest is one of the desired traits. All the IPB curly fruit chilies (G1-G5) showed significantly shorter time to harvest than the two control varieties, "Laris" and "Kastilo" F1 hybrid. However, in the largefruit chili peppers the harvest age of the control was significantly shorter than that of curly-fruit chili lines ( Table 2). All IPB large fruit chili (G8-G14), except for G9, had similar harvest age as the control large chili varieties "Anies IPB", "Seloka IPB", and "Gada" F1 hybrids, whereas the large fruit chili genotype G9 has a longer harvest age than other chili lines in the study. The longer time to harvest could be due to the late-formation of the fruit. The efficiency in harvesting can be related to plant height; for example, tall rice  varieties are prone to lodging, but short-posture varieties are more challenging to harvest (Gunarsih, 2016).
Fruit length of chili in the three different environments ranges from 10.68 cm to 16.55 cm (Table 3). All IPB curly-fruit chili (G1-G5) produced significantly longer fruits than the control varieties, whereas the IPB large fruit chili (G8-G14) had similar fruit length to the control ("Anies IPB", "Seloka IPB", and "Gada" F1 hybrids), except for G12, which had significantly longer fruit (14.99 cm) than the control large chili ( Table 3).
The fruit diameter of the different chili genotypes in the three environments ranged from 7.33 to 10.56 mm for the curly-fruit,s and 11.74 to 13.48 mm for the large-fruit chilli ( Table 4). The fruit diameter of the IPB curly-fruit chili (G1-G4) was not significantly different from those of the control varieties, "Laris" and "Kastilo". G5, however, had a significantly larger fruit diameter compared to "Laris". For the large-fruit chili, most of the IPB genotypes (G8-G14) produced fruit with a diameter that was similar to the control varieties "Anies IPB", "Seloka IPB", and "Gada" F1 hybrids. G11, however, had fruits with a significantly greater diameter than the control large-fruit chili Anies. According to Sujitno and Dianawati (2015) plant height, fruit diameter, and fruit length affect fruit production. In addition, Sharma et al. (2010) stated that fruit length positively correlate with fruit weight per plant.
The weight per fruit of the chili genotypes from three locations ranged from 3.87 to 7.25 g for the curly-fruit chilies, and 8.32 to 10.70 g for the large-fruit chilies ( Table 5). The weight per fruit of all IPB curly-fruit genotypes (G1-G5) was significantly heavier than the two control varieties, "Laris" and "Kastilo" F1, and among all curly-fruit chilies, G5 was the heaviest (Table 5). However, in the large chilies, the weight per fruit of all genotypes was not significantly different.
The number of fruits per plant in the chili genotypes ranged from 73.86 to 136.75 (Table 6). The average number of fruits per plant of the IPB curly-fruit chili (G1, G2, G3, G5) and "Laris" were significantly lower than those of the "Kastilo" F1 hybrid and G4 (Table  6). For the large-fruit chili, some IPB-developed lines (G9-G12) did not produce as many fruits as the control varieties, whereas G8 and G14 produced a similar number of fruits per plant to the control varieties. Environmental factors affect the number of fruits per plant (Table 5). However, Asnijar (2013) stated that  Notes: Values followed by the same lowercase letter in each environment column and the mean genotype and the same capital letter on the environmental average row shows no significant differences based on the Tukey test at α < 0.05. Notes: Values followed by the same lowercase letter in each environment column and the mean genotype, and the same capital letter on the environmental average row shows no significant differences based on the Tukey test at α < 0.05.
in addition to environmental factors, plant growth and production are also influenced by the genetic potential of a variety. Previously, Syukur et al. (2010) reported that several parameters of the chili growth and production are known to be more determined by genetic factors than by the environment.
The average fruit weight of the chili genotypes in the three environments ranged from 227.02 to 626.87 g per plant (Table 7). All the IPB curly-fruit chili (G1-G5) had greater fruit weight per plant than the control varieties "Laris" and "Kastilo" F1. The fruit weight per plant of all IPB large-fruit chili (G8-G14) was similar to those from the control varieties. Fruit weight character is a quantitative character that is influenced by environment. Geneva et al. (2018) stated that planting in areas with different agro-climates would significantly impact yield characteristics, including fruit size. Thus, each genotype might have a different yield potential according to the genetical make up and the plant's ability to adapt to its environment. Genotype and environment interacted in affecting fruit weight per plant, showing that genotypes with high yield potential at specific locations do not necessarily mean that the yield would remain high in other locations. In other words, the performance of a particular genotype is significantly influenced by various environmental conditions (Lestari et al., 2010).
Genotypic factors significantly influenced the average chili production per hectare (Table 1). The chili's average productivity in the three environments ranged from 8.78 to 10.54 t. ha -1 (Table 8), whereas the average national chili productivity is 9.10 t.ha -1 (BPS, 2019). According to Agastya et al. (2017), the low red chili pepper production is caused mainly by pests, plant diseases, and weeds. Dalimunthe et al. (2015) and Dewi et al. (2016) also stated that a vector of viruses from the Caulimoviridae and Luteoviridae families could significantly reduce chili yields (Kanakala and Ghanim, 2016), i.e. up to 58% in the Sukada et al. (2014) study. However, pest and diseases were all under control in this study. The productivity of the red chili pepper (Table 8) and the fruit size of the IPB lines (Tables 3 and 4) were not significantly different from the control varieties. Therefore, the IPB curly and large fruit red chili pepper have excellent potentials to be further developed into superior varieties.  Notes: Values followed by the same lowercase letter in each environment column and the mean genotype, and the same capital letter on the environmental average row shows no significant difference based on the DMR test at α < 0.05.

Conclusion
The growth performance of the 11 IPB-developed red chili pepper, as reflected by the time to harvest, fruit length, fruit diameter, weight per fruit, number of fruits per plant, fruit weight per plant, and their productivity, are influenced by the intrinsic factor (their genotype), the extrinsic factors (environments), and the interaction of both genotype and environment. The IPB curly-fruit (G1-G5) and the large-fruit lines (G8-G14) had a similar or better performances than the control curly-fruit "Laris" and "Kastilo" F1, "Anies IPB", "Seloka IPB", and to the large-fruit control "Gada" F1. Therefore, all of the IPB large and curly-fruit red chili pepper lines have great potentials to be developed into superior varieties.