Correlation between growth and yield of chili pepper cultivated in histisols

Correlations between plant traits is commonly applied in selection to increase effectiveness, and the path analysis can separate them into direct and indirect impacts. This research studied the closeness of the relationships between characters and decomposed it into a direct and indirect relationship between 14 chili genotypes on peat soils. This research was conducted from June 2022 to October 2022 in an agricultural zone station, University of Bengkulu. The soil used is peat soil. A randomized completely block design with three replications of 14 chili genotypes treatment was used to evaluate the study. Each genotype was planted in beds, with 2 genotypes and 20 plants per genotype. Observational data were then analyzed statistically using the correlation formula followed by significant and cross-finding tests using Microsoft Excel. The results showed that the growth characteristics and yield components such as plant height, leaf width, number of primary branches, number of primary branches, number of dichotomies, and number of fruits per plant were positively correlated with chili pepper yields. The determining characteristics for high chili yield on peatland were the number of fruits per plant, the number of dichotomies and the width of the leaves.


Introduction
Chili pepper (Capsicum annuum L.) is an agricultural product with high economic value worldwide.Chilies give a spicy taste to dishes and it is widely consumed as a fresh material for the food and pharmaceutical industries.Chili productivity in Indonesia in 2019 was 7.62 tons ha-1, but decreased in 2020 to 6.24 tons ha-1 [1].World chili productivity data shows that China is higher, reaching 22 tons ha -1 [2].From these data, it shows that chili pepper productivity in Indonesia needs to be increased.
Many factors cause low chili pepper productivity, including quality seeds and reduced fertile land.So, the development of planting chilies on marginal lands, for example, peatlands, is an alternative.Peatlands are water-saturated lands composed of organic matter with a C-organic content of > 12%, formed from the accumulation of decayed plant remains and tissues with a thickness of more than 50 cm [3].Peat soils have a pH of 3 to 4, with a relatively high level of acidity, and have a low amount of plant-available N. The P-organic element is the most abundant element of the P element found in peat soil.In addition, peat does not have microelements and is highly bound by organic matter, making it unavailable for plants.Peat soils naturally have low levels of macro and micronutrients [4].
New chili varieties that are superior and adaptive to peatland conditions are needed, because peatland conditions are generally not suitable for chili peppers.Varieties that are considered superior include those with high yields, disease resistance, and other characteristics [5].Superior varieties have 1302 (2024) 012013 IOP Publishing doi:10.1088/1755-1315/1302/1/012013 2 been produced through a series of plant breeding activities and to date no superior chili varieties have been obtained for peatlands.For this reason, research on chili breeding is needed on peatlands.
Breeding is basically a selection activity, while selection of yield characters is difficult, because yield is a quantitative trait that is influenced by many genes.For this reason, it is necessary to look for other characters that are more easily observed which are related to the results for selection efficiency [6].Correlation between traits is a common phenomenon that occurs in plants.Correlations between plant traits can be used as a basis for selection programs to increase selection effectiveness [7].There is a positive relationship between the number of fruits per plant and the weight of fruit per plant and the harvest age of cayenne pepper plants [8].The results of research by [9] showed that plant height at the end of harvest and the number of primary branches is factors for harvest production in red chili plants.
Correlation analysis alone is not enough to explain the causal relationship between characters, so path analysis is needed [10].Cross-printing is an analytical method to better understand the characters involved in the relationship between traits, and separate the correlation into direct and indirect effects [11].Cross-printing is the development of the correlation analysis method, which can explain the relationship between characters by decomposing the correlation coefficient into direct and indirect influences [12].Cross-printing has been widely used to explain cause-and-effect relationships of traits that determine the range of quantitative traits such as yield to yield components in plants.This study aims to measure the closeness of the relationship between characters and decompose it into direct and indirect relationships of 14 chili genotypes cultivated on peatlands.

Materials and methods
The works were conducted from June 2022 to October 2022 at the agricultural zone station, Agricultural Faculty, University of Bengkulu.A randomized completely block design with one factor and three replications, consisting of 14 treatments within 14 chili genotypes was used in this study.In each bed there were 2 different genotypes with a total of 21 beds, each bed consisted of 40 plants, so there were 840 plants, then 5 plants were taken per genotype for each block as sample plants.
The stages of this research included soil analysis, land preparation, seeding, planting, sampling, stakes, maintenance and harvesting.Soil analysis begins by taking soil samples from 5 different points at a depth of 20 cm on the land used.Each point of the soil sample taken as much as 0.5 kg is then mixed in a bucket and then mixed thoroughly.Soil that has been stirred in a bucket, taken as much as 0.5 kg and taken to the Laboratory of Soil Science, Agriculture Faculty, University of Bengkulu to be analyzed for pH value and the content of N, P, K, and C-organic.
The land was processed by using a hoe to a depth of 20 cm.Furthermore, on the land made beds with a width of 100 cm, a height of 30 cm, and a distance of 50 cm between the beds.The land was given dolomite lime to increase soil pH at a dose of 8.34 tons/ha [13].The land that has been given lime is stirred so that the lime is mixed with the soil.The next work is the installation of plastic mulch in each trial plot.
The chili seeds used in this study were first sown in a screen house.The seeding medium consists of a mixture of fine soil and manure (1:1).The container or container for the seedlings used for the seedlings is a 128-hole pottery.Before sowing, all the chili seeds are soaked in warm water overnight, then drained and sown immediately.
Planting of seeds in beds is done after 4 weeks after sowing.Before planting, holes were made in the mulch, using used cans according to the spacing of the plants used, namely 50 cm x 60 cm [14].Planting is done in the afternoon with one seed per planting hole.The stake used is split bamboo with a width of 3 cm and a length of 1 m.The stakes are installed before the plants are one month old.Plant support is done by sticking a stake near the stem of the chili plant as deep as 20-25 cm.The stems of the chili plants are tied to the stakes that have been installed.Experimental data was taken 5 plants per genotype of each plot.The variables observed were plant growth, plant yield components and plant yields when cultivated on peatland.The value of a simple linear correlation coefficient is calculated 3 based on the formula [15].Pearson correlation analysis was used to evaluate the closeness relationship between the characters [16].

Result and discussion
Correlation analysis between chili plant characters resulted varying values.The height of plant has a close relationship with canopy width, number of primary branches, dichotomy height, number of dichotomies, number of fruit and fruit weight (Table 1).Tall plants generally have a high dichotomous height.Tall plants have a large number of branches, number of fruits and fruit weight.[17] stated that chili plant height was significantly correlated with fruit weight per plant (0.80).Tall plants get a more optimal supply of sunlight, making photosynthesis more optimal and producing large yields of chilies.Chili leaf width has a significant correlation with the dichotomous branch numbers and fruit weight per plant, with values of 0.63 and 0.51 respectively (Table 1).These results indicate that chili plants that have wide leaves will have a large number of dichotomous branches.Chili fruit emerges from dichotomous branches, so there will be more fruit and the fruit weight per plant will be higher.Chili plants with a large number of branches will produce a lot of fruit [18].
The number of primary chili branches has a very significant relationship with dichotomous height (r = 0.75) and number of dichotomous branches (r = 0.69).These three characters are positively and closely correlated with the number of fruits per plant.This shows that chili plants that have many primary branches and dichotomies will generally bear a lot of fruit and the fruit weight per plant will be high.[19].reported that fresh fruit weight per plant was closely and positively related to the number of fruits.[20] and [21] stated that the number of primary chili branches is closely related to the number of fruits per plant.
The dichotomous height of chili plants was positively and very significantly correlated with the number of fruit (r = 0.67).Chili plants with higher dichotomies will produce more fruit.The higher the dichotomous height of chili plants, the farther the chili fruit is from the ground.This condition can reduce water splashing from the ground which is a source of fungal infections.Furthermore, the weight of the fresh chilies will be better; the production will be higher [22].
The number of stomata on chili plants is significantly correlation with primary branches number (r = 0.53), the height of the dichotomies (r = 0.58), and dichotomies number (r = 0.56).high and many and many primary branches too.The number of stomata is related to the density of stomata and the porous size of the stomata, so that it can increase the plant's transpiration process.The higher the plant transpiration rate, the nutrient uptake will increase, this will affect plant growth [9].
The fruit number was significantly and closely correlated with fruit weight per plant (0.82).This shows that chili plants that bear a lot of fruit usually have a high fruit weight per plant.Several other studies also state the same thing, if the weight of fruit per plant has a positive correlation with the number of fruit and fruit length [7].Correlation between yield components with yield and other quantitative characters helps in understanding the relationship between characters.the.The main cause of relationships between characters is due to the action of pleiotropic genes or linkage or both [23] Pleotropy is the event of the emergence of two or more different characters that are controlled by one gene.Linkage is the event of the emergence of two or more characters caused by two or more genes joining on the same chromosome.[24] reported a close relationship between the number of fruit per plant and the weight of fruit per chili plant.[25] reported that the number of primary branches has a close and positive relationship with the number of fruit and fruit weight per plant.
Number of fruits correlated positively with fruit weight per plant (0.82).It shows the chili plants that bear a lot of fruit usually have a high fruit weight per plant.Several other studies have also stated the same thing, if fruit weight per plant has correlation with fruit number and fruit length [7].Correlation between the outcome components and the outcomes and other quantitative characteristics helps in understanding the relationship between these characteristics.The main cause of the relationship between characters is due to the action of pleiotropic or linkage genes or both [23].Pleotropy is the emergence of two or more different characters that are controlled by one gene.Linkage is the emergence of two or more characters caused by two or more genes joining the same chromosome.
Fruit weight per plant has a close and positive correlation with plant height, leaf width, number of primary branches, number of dichotomies, and number of fruits per plant.Characters with positive correlation values to production characters can be used in plant breeding programs to increase yields through selection activities [26].
Path analysis shows the direct and indirect relationships of each growth component, yield component with results.Characters continued into cross-printing are characters that have a real and very real correlation with chili plant yield (fruit weight per plant).Traits that did not correlate with fruit weight per plant were not included in the trajectory analysis [27].The results of cross-sectional growth components, yield components and yield/fruit weight per plant are presented in Table 2. Based on guidelines [16] the fruit numbers per plant shows close and positive relationship to the yield of chili plants in the peatlands.It also has a direct effect (0.58) almost equivalent to the total correlation (0.82).[9] stated that the total number of fruits per plant has a direct positive influence on the weight of fruit per plant.Plant height is included in the second guideline because it has a negative direct influence value (-0.17), meaning that plant height has an indirect effect on chili plant yield (fruit weight per plant).Increasing yield per plant is carried out through four characters, namely leaf width, number of primary branches, number of dichotomous branches and number of fruits.Growth components that have a direct positive influence on chili production are shown on the parameters of stem diameter, crown width, branch numbers, fruit numbers, fruit length and weight.
Classified the influence value of cross analysis into five criteria, namely a value of 0.00-0.09including negligible criteria, a value of 0.10-0.19including low, a value of 0.20-0.29 including medium, and a value 0.30-0.99 is high [28].So, the number of primary branches is a negligible criterion, leaf width and number of dichotoms are medium criteria, while the number of fruits is high.
The fruit numbers are the greatest direct influence and it is almost equal to the total influence, so the number of fruits really has a direct effect on fruit weight (0.59) from the total influence (0.82), then leaf width (0.17) and dichotomous sum (0.27).The number of fruits has the greatest direct influence on the yield of chili plants [29].[30] reported that fruit weight, fruit diameter, fruit length, branch numbers and fruit numbers were directly related to fruit weight per plant.[31} reported that the fresh weight of fruit per plant is determined by the length of the fruit, the number of branches and the total weight of green fruit per plant.

Conclusion
Chili characters that have a positive and real relationship with yield are plant height, width of the leaves, number of primary branches, number of dichotomies, and number of fruits per plant.The fruit numbers per character have the greatest direct impact on fruit weight per plant, followed by other characters, namely the number of dichotomes and leaf width.The determining characters for high chili yield on peatland were the number of fruits per plant, number of dichotomies and Leaf width.

Table 1 .
Correlation between growth characteristics, yield components and yield in chili plants.

Table 2 .
Direct and indirect effects of growth characters with fruit weight per plant.