Investigation of Plant Density and Biological Fertilizer Effects on Agronomy Characteristics, Yield Seed and Yield Components of Commercial Cultivars of three Millet Species

In recent years, due to climate change, the planting of millets has become of particular importance, necessitating conducting further research on their quantitative and qualitative attributes. Pearl millet (Pennisetum glaucum L.) is widely known as a multipurpose crop in many regions of the world. It provides nutritious food for humans, feeds for poultry, and fodder for ruminants. About 20 different species of millet have been cultivated throughout the world at different points in time. Commonly cultivated millet species include proso millet (Panicum miliaceum L.), pearl millet (Pennisetum glaucum L.R. Br.), finger millet (Eleusine coracana), Kodo millet (Paspalum setaceum), foxtail millet (Setaria italica L. Beauv.). Little millet provides excellent support for nervous system health by helping to restore nerve cell function, regenerate myelin fiber, and intensify brain cell metabolism. Millets are also rich in micronutrients such as niacin, B-complex vitamins, Vitamin B6, and folic acid. Millets generally contain significant amounts of essential amino acids, particularly those containing sulfur (methionine and cysteine) ( Torabi, 2015). Plant density is among the agricultural practices that greatly influences grain yield and yield components of pearl millet as it determines the inter-and intra-plant competition for groundwater and soil nutrients during the growing season. Due to the development of human societies, food security has become a priority(Khajeh pour, 2012). Technological advancements and the introduction of chemical fertilizers and pesticides have provided sufficient quantities of food in recent decades, but food quality is questioned. Fertilizers from natural sources might be a practical solution. Coastal farmers in various countries have been applying seaweed for crop growth and development for many years. Nowadays, with technological development, some species of seaweed such as Ascophyllum nodosum are cultivated and processed as seaweed extract alone or mixed with other fertilizers to be used by farmers) Manea and Abbas, 2018.)

To investigate the effects of different densities of millet and bio-fertilizer application on morphological and physiological yield and yield components of three millet cultivars, a factorial experiment in a randomized complete block design with three replications was conducted in Mashhad in 2021. In the experiment, three density levels of millet (300,000, 400,000, and 500,000 plants per hectare), and two levels of seaweed (Ascophyllum nodosum) bio-fertilizer in quantity of 0 and 1 L per hectare, as well as three cultivars of millet (Bastan, Pishahang, and Mehran) were applied. In this experiment, grain yield, biomass yield, harvest index, 1000-seed weight, plant height and protein percentage were measured.

The analysis of variance showed that the effects of cultivar and density on grain yield were significant at the probability of 1% where the highest grain yield with an average of 4444.1 kg/ha was obtained from Mehran cultivar at a density of 400 thousand plants per hectare. The lowest was related to Pishahang cultivar at a density of 400,000 plants per hectare with an average yield of 2321.5 kg per hectare. The effect of bio-fertilizer application was also significant on the yield and yield components at the probability of 1%. The highest harvest index value (0.29) was obtained from the Mehran cultivar at a density of 400,000 plants per hectare. The examination of the trend of change in the biological yield and harvest index of this cultivar also indicated that with increasing density, the biological yield increased and the harvest index decreased. Additionally, the highest biomass yield (7629/6 kg/ha) was observed in Pishahang cultivar at a density of 400,000 plants per hectare, both by bio-fertilizer application.