Assembling corn varieties containing high amylopectin and high productivity

It is imperative that fluffy corn be developed as a substitute staple grain at this time. The goal of this research is to produce high-yielding corn cultivars with a high amylopectin content. This study had a randomized block design and using the Back Cross method. Plant three rows of the Srikandi Putih variety and one row of local waxy corn in the first year. F1 was created by crossing the Local Waxy Corn (♂) with the Srikandi Putih Variety (♀). F1 is planted in two rows, while F2 is produced by selfing. The second year, 105 F2 samples’ seeds were examined for amylopectin content before being chosen. After planting the chosen F2, it selfes to create F3. 100 rows of F3 were sown, and 263 F3 plants (♀) were chosen for backcrossing with the Srikandi Putih Variety (♂), yielding BC1F1. The following seed amylopectin levels tended to rise as selection proceeded, according to the results: F1 (74.25%), F2 (74.80%%), F3 (76.60%), and BC1F1 (79.15%). The following seed production per hectare was achieved between 2018 and 2019: F1 (2.93 t), F2 (3.05 t), F3 (4.61 t), and BC1F1 (5.09 t).


Introduction
Although maize is one of the cereal commodities that also includes good nutrients for human body, only a small fraction of the population like eating it.In Indonesia, corn is the second most popular staple meal after rice.According to the study's findings, cereal grains make up 1/4 of the total energy obtained and are a good source of vitamins and protein [1].This suggests that maize might be transformed into a substitute staple food item to lessen the rising amount of rice consumed.The White Srikandi type is less fluffy but has a comparatively good production.Corn is now mostly utilized to make corn oil, flour, and snacks in addition to being used as feed.Use as a mainstay food is still rather restricted.The population needs other staple crops, such corn, as an alternative to rice, in order to become less dependent on it.Corn must have better qualities, such as taste and nutritional value, if it is to be used as a staple meal.Combining two features from separate maize cultivars is therefore required.
Although the Srikandi Putih type has a high protein content and great productivity, its lack of a smooth taste makes it unsuitable for use as a parent.Local waxy corn is another parent that can be a companion.The South Sulawesi region has an abundance of this native grain.Both the young corn and the processed aged seeds of this indigenous waxy corn are highly favored by the public due to their deliciousness.Although there is little output, this local waxy corn feels fluffier due to its high amylopectin content.It is necessary to combine the exceptional qualities of these two varieties of corn with persistent plant breeding methods.The estimation of genetic and phenotypic parameters during the selection cycle is one of the elements that determines the efficacy of recurrent selection.Breeding programs might utilize these estimations as a reference for deciding on breeding tactics, the level of 1302 (2024) 012034 IOP Publishing doi:10.1088/1755-1315/1302/1/012034 2 selection to be applied, how to assess trait variety, and whether or not to introduce additional parents.Furthermore, these calculations allow one to assess the viability of breeding programs and forecast genetic gains for next selection cycles [2,3].
A particular kind of corn known as "waxy corn" differs from other varieties in that the seed endosperm of waxy corn contains more amylopectin than amylose.This is because seeds with a high amylopectin concentration express the recessive waxy (wx) or Chinese waxy (wx-c) gene [4].In order to produce corn with the required unique qualities, donor genes from special corn with a high amylopectin content can be integrated into high quality, high productivity protein corn using the backcross breeding technique.Typically, the endosperm of dent corn comprises 25-30% amylose and 70-75% amylopectin [5].Waxy maize, sometimes referred to as "sticky" or "glutinous" maize, has 95-100% amylopectin, as opposed to regular maize's 70-75% [6].The productivity of waxy corn is often only 2-2.5 t/ha.The high amylopectin level in seed starch is intimately linked to corn's fluffier flavor.In addition, waxy maize is a unique variety of corn that has high levels of antioxidants and anthocyanin chemicals [7,8].Two glucose polymer molecules, amylose and amylopectin, make up starch.The botanical source of amylose, a straight chain component, and amylopectin, a branched chain component, determines the molecular weight of each compound.
Amylose is a polysaccharide having α-1,4 glycosidic linkages that is helical and straight chain.Amylopectin's branching point is represented by an α-1,6 bond.The amylose chain contains between 250 and 350 units of glucose [9].There exists a positive correlation between the degree of retrogradation and the length of the amylopectin branch chain [10,11].The three primary components of starch are amylose, amylopectin, and intermediary substances including proteins and lipids.These elements affect the amylographic and functional characteristics of corn flour.Depending on the origin, maturity level, and growth conditions of the plant, normal starch typically comprises 15-30% amylose.Sticky starch has a low amylose content (0-8% amylose), whereas high amylose starches have 50% or more amylose [12,13].When the amylopectin content of local waxy corn varieties and Srikandi Putih variations is compared, Takalar Waxy Corn has a content of 94.21%, whereas Srikandi Putih Variety has 69.40% [14].The goal of this research is to produce maize varieties with high productivity and high amylopectin content.

Research Techniques
The first year of research yielded the F1 and F2 genotypes, whereas the second year of research yielded the F3 and BC1F1 genotypes.The research was conducted in Bajeng, Gowa Regency, South Sulawesi Province, Indonesia, during the first and second years.Time of implementation: March 2018-December 2019.The following materials were employed in this study: F1 and F2 seeds, F3 seeds, BC1F1 seeds, Srikandi Putih Variety corn seeds, and Local Waxy corn Variety seeds.Back-Cross Breeding, a simpler technique with a randomized block design, was employed in this investigation.During the two years that this research was conducted, two generations were collected each year, for a total of four generations.Planting three rows of recipient parents (Srikandi Putih Variety) and one row of donor elders (local waxy corn) marked the beginning of the research method's first year.Every row has forty plants on it.To create the F1 genotype, local waxy corn (♂) and Srikandi Putih (♀) were crossed.The best F1 genotype was chosen, and forty seedlings were planted in each of the two rows.21 of the plants self-dried to yield the F2 genotype.In the second year of the method's implementation, 105 Genotype F2 samples were analyzed based on the seeds' amylopectin content.26 Genotype F2 plants with high amylopectin content were then chosen.Up to 20 rows of plants bearing the chosen F2 genotypes were planted, and 210 plants were selfed to provide the F3 genotype.After planting 100 F3 genotype lines, the top 26 rows were chosen.In order to create the BC1F1 genotype, 263 F3 genotype (♀) plants were chosen and then crossed back with the Srikandi Putih Variety (♂).

. Amylopectin content of seeds
The results of the analysis of variance indicated that the amylopectin content of the seeds was significantly influenced by the variety/genotype.Table 1 displays the results of the LSD0.05 test.
While the amylopectin levels between the F1 and F2 genotypes were not significantly different, they were both higher and significantly different from the Srikandi Putih variety.Table 1 displays the highest amylopectin levels in the local waxy corn variety and significantly different from all genotypes tested.The Srikandi Putih variety differed significantly from all the genotypes evaluated and had the greatest protein content.The F1 and F2 genotypes' protein levels were not substantially different from one another, but they were both higher and markedly different from the waxy corn grown nearby.Amylopectin levels in F1 started to rise and climbed considerably more in F2, showing a positive change in character that distinguished them greatly from the female parent variety of Srikandi Putih.Genetics controls the amount of amylose and amylopectin in corn kernels.Generally speaking, the amylose content of dent and flint corn endosperm is 25-30%, while the amylopectin content is 70-75%.Nearly all of the starch in waxy maize is amylopectin.The chemical makeup of starch is influenced by a single waxy gene (wx), a recessive epistasis on chromosome nine, which results in very little amylose accumulation [16].The study's findings showed that, in comparison to the local waxy corn variety's parents, the F1 protein (genotype originating from crossing Srikandi Putih x Local Waxy maize Variety) increased by 8.1% [17].

Diameter and Length of Ears
The results of the analysis of variance indicated that ear length and ear diameter were significantly influenced by the variety/genotype.While the F1 and F2 genotypes did not significantly differ from the local Waxy corn, the maximum ear length in the Srikandi Putih variety was, according to the results of the LSD0.05 test in Table 2.Moreover, there was no significant difference in ear diameter between the F2 and Srikandi Putih genotypes, but both genotypes differed significantly from the F1 and local waxy corn varieties.This suggests that the cob's diameter and length parameters have started to alter.Numerous genes affect the diameter and length of the cob.

Seed production per hectare, weight of 100 seeds, and seed weight per plant
The weight of 100 seeds, the weight of seeds per plant, and the number of seeds produced per hectare were all significantly impacted by the variety/genotype, according to the analysis of variance.The weight of 100 seeds in the Srikandi Putih variety was the highest and was substantially different from all the genotypes examined (LSD 0.05 test in Table 3).In contrast, the F1 and F2 genotypes of the local waxy corn did not significantly differ from each other.Additionally, the Srikandi Putih variety had the highest seed weight per plant and the highest seed production per hectare, both of which significantly differed from all other genotypes tested.In contrast, the local waxy corn did not differ significantly from the F1 genotype, but the F2 genotype was higher and significantly different from the local waxy corn.
This suggests that generally speaking, the traits of the F1 and F2 generations have changed.Table 3's data on 100-seed weight, seed weight per plant, and seed production per hectare demonstrates an upward trend from F1 to F2.This is because segregation occurs throughout the crossing process, resulting in variations in production within each generation.One of the elements contributing to the diversity of plant phenotypes is variations in genetic structure [18].Genetic variability, according to the study's findings, is the variety of individual qualities that emerge from genetic elements in a community.Genetic recombination as a result of crossing and mutations, polyploidization, and mixing of breeding materials can all result in genetic variety [20].

Seed's amylopectin content
The results of the analysis of variance indicated that the amylopectin content of the seeds was significantly influenced by the variety/genotype.Table 4 displays the results of the LSD0.05 test.The greatest local amounts of waxy corn amylopectin are displayed in Table 4, which also differs significantly from all other genotypes examined.The amounts of amylopectin in the BC1F1 and F3 genotypes were not statistically different from Srikandi Putih, but they were both considerably higher.This demonstrated that the levels of amylopectin in F3 and BC1F1 tended to increase and differed significantly from those in the female parent, Srikandi Putih Variety.This indicates that the more sophisticated the selection process, the higher the amounts of amylopectin.
Local corn known as "waxy corn" has tiny ears that measure 10 to 12 mm in diameter and is extremely susceptible to downy mildew.The recessive gene wx controls waxy character (waxy corn).Transferring the wx gene to non-waxy corn is simple [19].Waxy corn starch, identified subjectively by a brownish-red response on the inside of the dipped seeds, can be identified using potassium iodide solution (KI2, also called iodine solution).Pollen from waxy maize turns reddish brown when it reacts with iodine solution, while pollen from non-waxy corn exhibits a blue to black reaction.

The length and diameter of the ear
The results of the analysis of variance indicated that ear length and ear diameter were significantly influenced by the variety/genotype.The ear length and ear diameter of BC1F1 were not significantly different from the Srikandi Putih Variety, but they were longer and considerably different from the local waxy corn, according to Table 5's LSD0.05 test.From Genotype F3 to Genotype BC1F1, there was a propensity for the ear's length and diameter to expand.This demonstrates how, following back-crossing, the length and diameter characters of the Srikandi Putih Variety as the recipient parents have started to progressively reappear.According to the study's findings, the desired gene can be transferred from donor to recurrent parent via the backcross technique [20].

Seed production per hectare, weight of 100 seeds, and seed weight per plant
The weight of 100 seeds, the weight of seeds per plant, and the number of seeds produced per hectare were all significantly impacted by the variety/genotype, according to the analysis of variance.
The weight of 100 seeds of the Srikandi Putih variety is shown in Table 6, and it was greater and statistically different for every examined genotype.Compared to the local waxy corn, the BC1F1 and 6 F3 genotypes were higher and much different.The highest variety of Srikandi Putih was shown in Table 6 by seed weight per plant and seed output per ha, which differed considerably from all other genotypes examined save for the BC1F1 genotype.Compared to the local waxy corn, the BC1F1 and F3 genotypes were higher and much different.
One of the characteristics of maize plants that dictates their high output per hectare is their grain yield weight.Selection intended to improve production results must take other characteristics into consideration because the inheritance of these characters is complex and can involve many characters [21].According to the study's findings, appropriate selection can result in a 4% increase in seed output, or genetic gain [22].
3) The Srikandi Putih Variety's high productivity trait inherited from the female parent and the male parent's high amylopectin content have been handed down through the generations.
To create new kinds, more research is required to produce stable genotypes that are productive and have high amylopectin levels.

Table 1 .
Shows the amount of amylopectin in each examined genotype.
Note: at the LSD0.05 test, there is no significant difference between numbers that are preceded by the same letter

Table 2 .
Ear length and diameter of the various genotypes tested Note: numbers followed by the same letter are not significantly different at the LSD0.05 test 4

Table 3 .
Weight of one hundred seeds, weight of seeds per plant, and yield of seeds per hectare for each of the tested genotypes Note: at the LSD0.05 test, there is no significant difference between numbers that are preceded by the same letter

Table 4 .
Content of amylopectin in seeds examined from different genotypesNote: at the LSD0.05 test, there is no significant difference between numbers that are preceded by the same letter

Table 5 .
Ear diameter and length for the different genotypes examined

Table 6 .
Weight of one hundred seeds, weight of seeds per plant, and yield of seeds per hectare for each of the tested genotypes Note: at the LSD0.05 test, there is no significant difference between numbers that are preceded by the same letter