Ⅰ. INTRODUCTION
Barnyard millet (Echinochloa esculenta) is a warm-season annual C4 forage crop characterized by rapid growth, high biomass production, and adaptability to hot and humid environments. Its tolerance to relatively wet soil conditions makes it suitable for summer cultivation in paddy fields, where excessive soil moisture may limit the production of other upland forage crops (Lim et al., 2021;Park et al., 2022). Barnyard millet has also gained attention as an underutilized crop with potential for genetic improvement and adaptation to diverse production environments (Pradhan et al., 2024). Forage productivity of barnyard millet is strongly influenced by cultivation practices, growth duration, and developmental stage at harvest. Echinochloa millets are quantitative short-day plants, and cultivar differences in photoperiod sensitivity can result in variation in heading time. Under longer photoperiods, delayed head emergence was accompanied by greater shoot weight, suggesting that later-maturing genotypes may have a longer period for vegetative biomass accumulation before heading (Muldoon, 1985). Under field conditions, realization of this biomass potential also depends on the growing period available after sowing, as delayed sowing generally reduces growth, dry matter yield, and nutritive value under Korean growing conditions (Lee et al., 2013). Seeding density and planting method also influence stand establishment and dry matter production (Lee et al., 2021). In a recent study conducted in Canada, forage yield of Japanese millet (E. esculenta) was affected by developmental stage at harvest, with the highest annual dry matter yield obtained from a single harvest at the heading stage (Seguin, 2025). Collectively, these findings indicate that maturity and harvest timing are important factors in maximizing forage productivity. Barnyard millet can be integrated with winter forage crops such as Italian ryegrass (IRG) in paddy fields, providing an opportunity to increase annual forage production and improve land-use efficiency (Oh et al., 2021;Jung et al., 2023). In such winter–summer forage cropping systems, cultivar maturity is important because growth duration and heading date affect harvest scheduling and compatibility with preceding and subsequent crops. Therefore, cultivars with diverse maturity types are needed to provide greater flexibility under different regional growing conditions and cropping schedules. The National Institute of Animal Science (NIAS), Rural Development Administration, has developed domestic forage barnyard millet cultivars, including ‘Jo-on’ and ‘Da-on’, to improve forage productivity and diversify cultivar options. ‘Da-on’, developed from local germplasm collected on Jeju Island, is a mid-maturing cultivar with an average heading date of August 5 and exhibits an erect growth habit, lodging tolerance, and high forage productivity (Choi et al., 2025). However, further diversification of maturity types, particularly toward late maturity, is needed to broaden cultivar choice and accommodate different summer growing periods and forage cropping systems. To meet this need, NIAS developed ‘Man-on’ (breeding line BM4), a new late-maturing barnyard millet cultivar through pure-line selection from local germplasm collected on Jeju Island. ‘Man-on’ has an average heading date of August 30, showing a distinctly late-maturing growth habit. Therefore, this study was conducted to describe the breeding process of ‘Man-on’ and to evaluate its agronomic characteristics, forage productivity, adaptability, and nutritive value as a new late-maturing barnyard millet cultivar for summer forage production in Korea.
Ⅱ. MATERIALS AND METHODS
This study was conducted from 2016 to 2025 by the Forages Production Systems Division of the National Institute of Animal Science (NIAS), Rural Development Administration (RDA), to develop a new late-maturing barnyard millet (Echinochloa esculenta) cultivar with forage productivity and adaptability to domestic forage production systems.
1. Breeding process and line selection
The new barnyard millet cultivar ‘Man-on’ was developed through pure-line selection from local germplasm collected on Jeju Island in 2016. Here, “Jeju native” refers to the source germplasm used for selection, whereas ‘Jeju local’ is a registered cultivar used as the check. Individual plants with desirable agronomic characteristics were selected from the source population, followed by successive pure-line selection from 2018 to 2021. The selected BM4 line was evaluated in a yield trial at Cheonan in 2022 and subsequently advanced to regional adaptability trials from 2023 to 2025. The pedigree is shown in Fig. 1.
2. Evaluation of agronomic characteristics of ‘Man-on’
The agronomic performance of the barnyard millet breeding line ‘Man-on’ (BM4) was evaluated in a yield trial conducted in 2022 at the experimental field of the Forages Production Systems Division, National Institute of Animal Science (NIAS).
Major agronomic and morphological traits were assessed according to the standard crop characterization guidelines of the Korea Seed and Variety Service (KSVS).
3. Regional adaptability trials
Regional adaptability trials of the barnyard millet line ‘Man-on’ (BM4) were conducted from 2023 to 2025 at Cheonan and Jinju, with additional evaluations at Gimje in 2023–2024 and Pyeongchang in 2025. The trials were conducted to evaluate the adaptability, forage yield potential, and major agronomic characteristics of ‘Man-on’ in comparison with the Jeju local barnyard millet used as the check cultivar. The experiments were arranged in a randomized complete block design, with individual plots measuring 1.5 × 4 m. Sowing was conducted in May at each experimental site using a seeding rate of 20 kg/ha with drill sowing at 30 cm row spacing. Fertilizer management followed the official RDA guidelines for forage crops. Fertilizer was applied at rates of N–P2O5–K2O = 150–120–120 kg/ha. Nitrogen was applied at 40% of the total rate as basal fertilizer at sowing, with the remaining 60% top-dressed when the plants reached approximately 20 cm in height. The entire amounts of phosphorus and potassium were applied as basal fertilizer at sowing.
Major agronomic and morphological traits, including heading date, plant height, leaf characteristics, stem diameter, panicle characteristics, and lodging tolerance, were evaluated during the growing period. Forage yield was determined by harvesting the experimental plots at each trial site and calculating dry matter yield on a hectare basis.
4. Evaluation of disease and insect resistance
Natural occurrence of major diseases and insect damage was evaluated during the regional adaptability trials from 2023 to 2025. Leaf blight and Asian corn borer damage were visually assessed using a 1–9 scale, with lower scores indicating less damage.
5. Forage nutritive value analysis
For forage nutritive value analysis, representative subsamples of 200–300 g were collected from the forage biomass harvested at the heading stage. The samples were dried in a dry oven at 65°C for 72 h and subsequently ground using a Wiley mill fitted with a 20-mesh screen. The ground samples were stored in double-capped plastic containers protected from direct sunlight until analysis.
The nutritive value of ‘Man-on’ and the Jeju local barnyard millet used as the check was determined using standard laboratory procedures. Crude protein (CP) content was analyzed by the Kjeldahl method according to AOAC (1990) using an automated nitrogen analyzer (Kjeltec™ 2400 Autosampler System, Foss Tecator, Sweden). Acid detergent fiber (ADF) and neutral detergent fiber (NDF) concentrations were determined using an Ankom Fiber Analyzer (Ankom Technology, Macedon, NY, USA) according to the procedures of Goering and Van Soest (1970). Total digestible nutrients (TDN) were estimated from ADF concentrations using the equation (Holland et al., 1990).
6. Statistical analysis
Statistical analyses were performed using SAS software (version 9.4; SAS Institute, Cary, NC, USA). Differences in agronomic characteristics, dry matter yield, and forage nutritive value between ‘Man-on’ and the check were evaluated using Student’s t-test. Statistical significance was determined at p<0.05.
Ⅲ. RESULTS AND DISCUSSION
1. Morphological and agronomic characteristics of ‘Man-on’
The agronomic characteristics of ‘Man-on’ are summarized in Table 1. The cultivar exhibited an erect growth habit with relatively long and broad leaves and light-purple panicles. The panicles were conical in shape and predominantly horizontal in attitude. The average heading date of ‘Man-on’ was August 30, approximately four days earlier than that of the check (September 3). Although the cultivars were evaluated in separate trials, the heading date of ‘Man-on’ was 25 days later than the August 5 date reported for the mid-maturing cultivar ‘Da-on’ (Choi et al., 2025), supporting its classification as a late-maturing cultivar with a relatively long vegetative growth period. Harvest stage has been reported to markedly affect forage productivity in Japanese millet (Echinochloa esculenta), indicating that developmental duration and maturity are important considerations for forage utilization (Seguin, 2025). The mean plant height of ‘Man-on’ was 182.8 cm, compared with 193.0 cm for the Jeju local barnyard millet, although the difference was not statistically significant. The flag-leaf length and width of ‘Man-on’ were 32.5 and 2.9 cm, respectively, whereas those of the check were 31.4 and 2.3 cm, respectively. The stem diameter of ‘Man-on’ was 5.8 mm, which was slightly greater than that of the check (5.0 mm). In addition, ‘Man-on’ had a panicle length of 20.0 cm, compared with 18.6 cm for the check. Considerable variation in plant height, leaf characteristics, and inflorescence traits has been reported among barnyard millet germplasm, demonstrating the importance of these morphological traits in the characterization and selection of breeding materials (Sood et al., 2015;Amulya et al., 2026). Overall, ‘Man-on’ was characterized by late maturity, an erect growth habit, relatively broad leaves, and long panicles, supporting its suitability as a late-maturing cultivar for summer forage production.
2. Lodging, disease, and insect resistance
Lodging, leaf blight, and insect damage scores of ‘Man-on’ and the check are summarized in Table 2. The average lodging score of ‘Man-on’ was 2.6, similar to 2.5 for the check, and the difference was not statistically significant. The average leaf blight scores were 2.1 for ‘Man-on’ and 2.0 for the check, indicating similar responses under natural field conditions. Insect damage was minimal in both genotypes, with mean scores of 1.0 for each.
Despite its greater stem diameter, ‘Man-on’ had a lodging score similar to that of the check. This observation is consistent with a report on forage sorghum in which stem diameter was not significantly correlated with lodging index (Niu et al., 2026),Niu et al., 2026).
Biotic stresses, including fungal diseases and insect pests, are important constraints in barnyard millet production, and considerable variation in resistance has been reported among Echinochloa germplasm (Renganathan et al., 2020). The similar disease and insect damage scores observed in the present study indicate that ‘Man-on’ and the check showed comparable responses to the naturally occurring disease and insect pressure during the regional adaptability trials. However, because disease and insect responses were evaluated under natural field conditions rather than controlled inoculation or artificial infestation, further evaluation under controlled conditions would be necessary to determine specific levels of resistance.
3. Dry matter yield performance
The dry matter yield of ‘Man-on’ varied among the regional adaptability trial sites during the 2023–2025 growing seasons (Table 3). The mean dry matter yields of ‘Man-on’ were 14,826 kg/ha in Cheonan, 12,668 kg/ha in Jinju, 15,365 kg/ha in Gimje, and 17,219 kg/ha in Pyeongchang. Across all trial environments, ‘Man-on’ produced an overall mean dry matter yield of 14,492 kg/ha, corresponding to 96% of the yield of the check (15,110 kg/ha). The difference in dry matter yield between ‘Man-on’ and the check was not statistically significant (p>0.05). These results indicate that ‘Man-on’ maintained a level of forage productivity comparable to that of the check across the regional adaptability trials.
In addition to its comparable dry matter yield, ‘Man-on’ exhibited a distinct late-maturing growth habit, with vigorous vegetative growth and well-developed panicles at the heading stage (Fig. 2). The late heading of ‘Man-on’ may have extended the period of vegetative biomass accumulation, consistent with the greater shoot weight observed under delayed head emergence in Echinochloa millets (Muldoon, 1985). These characteristics suggest that ‘Man-on’ can provide an additional late-maturing cultivar option for summer forage production and may contribute to greater flexibility in forage cropping systems in Korea.
4. Forage nutritive value
The forage nutritive value of ‘Man-on’ is summarized in Table 4. At the heading stage, the crude protein (CP) content of ‘Man-on’ was 6.2%, which was significantly higher than that of the check (4.5%). The neutral detergent fiber (NDF) content was significantly lower in ‘Man-on’ (65.9%) than in the check (69.2%). Acid detergent fiber (ADF) content was 36.0% in ‘Man-on’ and 37.4% in the check, with no significant difference between them. The estimated total digestible nutrients (TDN) content of ‘Man-on’ was 60.5%, compared with 59.4% for the check, and the difference was not statistically significant.
These results indicate that ‘Man-on’ had a higher CP content and lower NDF concentration than the check at the heading stage, while ADF and TDN levels were comparable between the two genotypes. Late-heading barnyard millet has previously been reported to produce high dry matter yield but relatively low CP content under Korean growing conditions (Park et al., 2022). In this context, the significantly higher CP content and lower NDF concentration of ‘Man-on’ indicate forage-quality advantages over the late-maturing Jeju local barnyard millet. Overall, ‘Man-on’ showed favorable forage quality characteristics, supporting its potential use as a late-maturing forage cultivar for summer production.
Ⅳ. CONCLUSION
The breeding and evaluation program for the barnyard millet cultivar ‘Man-on’ (BM4) was conducted from 2016 to 2025 by the Forages Production Systems Division of the National Institute of Animal Science (NIAS), Rural Development Administration (RDA). ‘Man-on’ was developed through selection from local barnyard millet germplasm collected on Jeju Island and is characterized by an erect growth habit, relatively long and broad leaves, and light-purple panicles. Its average heading date was August 30, approximately four days earlier than that of the check cultivar, the Jeju local barnyard millet (September 3). Its heading date was 25 days later than the previously reported date for the mid-maturing cultivar ‘Da-on’, supporting its classification as a late-maturing cultivar. The mean plant height of ‘Man-on’ was 182.8 cm, compared with 193.0 cm for the check, with no significant difference between them. Regional adaptability trials conducted from 2023 to 2025 showed that ‘Man-on’ produced an average dry matter yield of 14,492 kg/ha, corresponding to 96% of that of the check (15,110 kg/ha), with no significant difference between the two genotypes. These results indicate that ‘Man-on’ maintained forage productivity comparable to that of the check across the regional adaptability trials. Forage nutritive value evaluated at the heading stage showed that ‘Man-on’ had a crude protein (CP) content of 6.2%, which was significantly higher than that of the check (4.5%). The neutral detergent fiber (NDF) content of ‘Man-on’ was significantly lower at 65.9%, compared with 69.2% for the check. Acid detergent fiber (ADF) contents were 36.0% and 37.4%, and total digestible nutrients (TDN) were 60.5% and 59.4% for ‘Man-on’ and the check, respectively, with no significant differences in these traits. Taken together, ‘Man-on’ combines a distinct late-maturing growth habit with forage productivity comparable to the check and favorable forage quality characteristics, particularly higher CP and lower NDF contents. These characteristics support its potential use as a late-maturing cultivar for diversifying summer forage production and cropping systems in Korea.
