Delta and Pine Land Company (D&PL) recently developed DP 444 BG/RR a new early-maturing variety that is receiving significant attention due to its high yield potential and improved fiber properties.  Field observations in 2002 suggested a consistent incidence of plants exhibiting a lack of apical dominance, commonly referred to as "split terminals."  D&PL technical service agronomists noted this phenomenon at every location observed in 2002 and regional agronomist Dr. Ken Lege will present a paper on the topic today during the Cotton Improvement Conference.

In a review of previously published research, Lege discusses the possible causes of split terminal plants or tipped out plants.  That research indicates splitting can result from a number of events that remove or damage the apical meristem, including insects, chemical or mechanical damage. 

Lege says "DP 444 BG/RR has a fairly consistent pattern of terminal splitting, occurring in about 24 percent of the plants of DP 444 BG/RR monitored over the past two years.  While the cause of the loss of apical dominance in this variety was not determined, data show it is not due to applications of glyphosate.  Further, with split terminals occurring at every location in 2002 and 2003, there is evidence that strongly suggests insect injury is not responsible as the likelihood of having insect populations infest the crops at the same stage (between nodes 2 and 3) and at such a consistent rate across a wide geographic area is very low." 

Because most prior research on terminal splitting suggests this early season terminal injury may induce vegetative growth and delay maturity, D&PL agronomists collected significant physiological data through plant mapping.

In reviewing D&PL data, Lege says, "split terminal plants contributed equally to crop yield, and did not influence any of the fiber properties. Split terminal plants had significantly fewer total nodes and significantly fewer fruiting nodes.  And while split terminal plants' flower initiation was significantly delayed, final maturity was not delayed.  D&PL data suggest that the occurrence of split terminal plants in DP 444 BG/RR did not alter the manner in which the variety should be managed for glyphosate applications, insect control, or harvest aid applications relative to other early-maturing varieties."

Delta and Pine Land Company is a commercial breeder, producer and marketer of cotton planting seed, as well as soybean seed in the Cotton Belt.  For almost 90 years, the Company has used its extensive cotton plant breeding programs drawing from a diverse germplasm base to develop improved varieties.  Delta and Pine Land (NYSE:  DLP), headquartered in Scott, Mississippi, has offices in eight states and facilities in several foreign countries.