Developing Functional Relationships between Sesame (Solanum indicum L.) Growth Development and Nitrogen Nutrition during Early-Season.

Developing functional relationships between sesame (Solanum indicum L.) growth development and nitrogen nutrition during early-season

Callie Ann Smith. Hunt Walne, Mark Shankle, and K. Raja Reddy

Functional relationships between leaf nitrogen (N) and sesame crop growth processes are not available. An outdoor pot-culture experiment was conducted to determine N deficiency effects on sesame, cv. “Seasaco S40” growth and development. Plants were grown in pots filled with fine sand and irrigated with full-strength Hoagland’s nutrient solution from emergence after ten days of sowing (DAS). After that, the treatments imposed were full-strength Hoagland’s nutrient solution (control, 100N), reduced N to 60, 20, 10 and 0% of the control and withheld N from the solution (0N) to 31 DAS. Growth including several root traits, photosynthesis, and leaf N were measured at the end of the experiment. Maximum growth rates were achieved at 5.3 g N kg^-1. Even though all growth rates declined with lower leaf N, leaf area expansion was more sensitive to leaf N among the shoot growth and developmental parameters. Among the root traits, root volume was more sensitive to lean N than other parameters. Among the plant-dry components, leaf dry weight had the greatest decrease while root/shoot ratio increased under N deficiency. The functional algorithms and critical leaf N levels for various growth processes will be useful for modeling and for managing sesame crop in the field.