Wednesday, November 15, 2006

Nitrogen and Water Use Efficiency of Staygreen Sorghum.

Sylvester Addy1, Muchha Reddy2, Nishantha Fernando3, and Carl Niedziela1. (1) North Carolina A&T State Univ, 1601 E Market St, Greensboro, NC 27411, (2) North Carolina State Univ, Dept of Natural Resources, Greensboro, NC 27411, (3) Dept of Natural Resources, NC A&T State Univ, Greensboro, NC 27411

Sorghum is highly adapted to the semi-arid environment and constitutes an important ingredient in the diet of millions of people within those regions. The semi-arid regions of the world are characterized by erratic rainfall and low nitrogen soils. Water and nitrogen are two major limiting factors for the growth and development of all cereal crops such as sorghum. Breeding programs have identified certain adaptations that present great promise for the development of crops that are tolerant to low levels of water and nitrogen. The Staygreen property of sorghum is a unique example of these adaptations. The Staygreen property enables some sorghum genotypes experience an extended period of foliar greenness during their post-anthesis period. A vital aspect of the Staygreen property is its high nitrogen use efficiency which enables it to produce higher levels of assimilates which provides the crop the ability to produce appreciable grain yields. A greenhouse study was conducted at NCA&T State University to evaluate the effect of low nitrogen and moisture levels in Staygreen sorghum variety BTx642. The experimental design was a 3x3 factorial design involving two factors: nitrogen and water, each with three levels. Nitrogen was applied at rates of 68, 101, 135 kg/ha. Staygreen Sorghum plants were subjected to soil water treatments: field capacity, one-half  and one-third field capacity. Leaf chlorophyll was measured by an SPAD – 502 chlorophyll meter during the growing season. Values for fresh leaf weight, root dry matter weight for the various treatments were not significant. Effects of water stress and N on other measurements like grain yield, plant height, days to flowering, stalk dry matter weight and numbers of senescing leaves were also taken during the period of growth.


Handout (.ppt format, 792.0 kb)