Introduction: In most countries of the world, research and progress in the production and management of fodder plants have been forgotten, so for the development and cultivation of fodder plants and the lack of fodder for livestock and also to reduce the pressure on pastures, the standard and scientific production of fodder should be increased compared to the effort and attention which is directed to other products, the fodder production has been neglected. Today, due to changes in weather conditions, population growth, and concerns about food security, the cultivation of millet has gained special importance; therefore, research on its quantity and quality is important.
Materials and Methods: To investigate the effect of density and biological fertilizer (Ascophyllum nodosum seaweed) on three varieties of millet, this experiment was carried out during the two crop years of 2019 and 2020, in fields located in Mehdi-Abad region (Keneh-Bist) and the Agricultural Research Center, respectively. It was done in Mashhad city. The factorial experiment was carried out as a randomized complete block design in three replications. The test factors include plant density in three levels of 300, 400, and 500 thousand plants per hectare with row spacing of 6.5, 5, and 4 cm and row spacing of 50 cm and the use of biological fertilizer in two levels: no use and Application of seaweed biological fertilizer (during two stages: the first stage at the time of tillering and the second stage when the panicum appears) at the rate of one liter per hectare (based on field studies) and spraying on three different species of millet (Panicum miliaceum var. Pishahang, Setaria italica var. Bastan, and Pennisetum gluacum var. Mehran) were implemented. During the plant's growth period, the necessary notes of the characteristics of its growth and reproduction included the number of leaves, the yield of fresh fodder, the weight of 1000 seeds, the period of seed filling, and the number of days until flowering. The exact time of harvesting green fodder was at the stage of 50% grain milkiness. Composite variance analysis was performed for two years with the assumption of randomness of the year factor using MSTATC software.
Results and Discussion: The combined analysis revealed significant effects of year, species, and their interactions on fresh forage yield. Specifically, year × species, year × density, species × density, species × fertilizer, density × fertilizer, species × density × fertilizer, and year × species × density × fertilizer interactions were significant for fresh forage yield. The highest yield was obtained in the first year from the Pishahang variety of Panicum miliaceum at a density of 300,000 plants per hectare without fertilizer. This yield was statistically similar to the yield of the Mehran variety of Pennisetum gluacum at a density of 500,000 plants per hectare with seaweed fertilizer. The lowest yield was recorded in the second year from the Bastan variety of Setaria italica at a density of 300,000 plants per hectare without fertilizer. At a density of 500,000 plants per hectare, there was no significant difference between fertilized and non-fertilized treatments, placing them in the same statistical group. The response of fresh forage yield to density and fertilizer application varied, with no specific pattern observed.
The analysis also indicated that the simple effects of year, species, and their interaction on days to flowering were significant. The Mehran variety of Pennisetum gluacum had the highest days to flowering in the first year, while the Pishahang variety of Panicum miliaceum had the lowest in the second year. In both years, Pishahang had fewer days to flowering compared to the other species. Overall, all species flowered earlier in the second year due to the faster temperature increase, accelerating growth.
For the grain filling period, the results showed significant simple effects of species, year, and their interaction. The Bastan variety of Setaria italica had the longest grain filling period in the first year, while the Mehran variety of Pennisetum gluacum had the shortest. The grain filling period for Bastan differed significantly between the two years, whereas the other species had consistent periods. These differences are attributed to genetic variations among the species. The thousand-grain weight results indicated that the length of the grain filling period significantly affected this trait, with Mehran and Bastan varieties having the highest and lowest weights, respectively.
Finally, the combined analysis showed significant effects of species, density, fertilizer, and their interactions on thousand-grain weight. The highest thousand-grain weight was obtained for the Bastan variety of foxtail millet at a density of 400,000 plants per hectare without fertilizer. The lowest weight was recorded for the Mehran variety of pearl millet at the same density with fertilizer. No significant difference was observed between fertilized and non-fertilized treatments at a density of 300,000 plants for the same species. Overall, the thousand-grain weight response to density and fertilizer treatments did not follow a specific pattern, potentially due to variations in time, frequency, and concentration of fertilizer application.
Conclusion: The study demonstrated significant differences in the traits of the investigated species, except for forage yield, for which the interaction effects of year, species, density, and fertilizer were observed. Panicum miliaceum var. Pishahang, at a density of 300,000 plants per hectare without fertilizer, achieved the highest forage yield in the first year. Pennisetum glaucum var. Mehran also showed promising results with 500,000 plants per hectare and the application of seaweed fertilizer. Overall, while specific species like Panicum miliaceum var. Pishahang and Setaria italica var. Bastan excelled in certain harvests, Pennisetum glaucum var. Mehran demonstrated consistent superiority across traits. For maximizing fodder yield, it is recommended to cultivate Panicum miliaceum var. Pishahang and Pennisetum glaucum var. Mehran. For higher seed harvest, Setaria italica var. Bastan is suggested. The varying responses to fertilizer indicate that genetic differences among species played a more critical role in trait performance.
The results underscore the need for tailored agronomic practices based on species-specific responses to density and fertilizer application. Future research should further explore these genetic variations to optimize forage production and quality.