Influence of temperature, moisture, and nitrogen on tillering of sorghum and pearl millet
General Material Designation
[Thesis]
First Statement of Responsibility
M. Saleem
Subsequent Statement of Responsibility
G. L. Posler
.PUBLICATION, DISTRIBUTION, ETC
Name of Publisher, Distributor, etc.
Kansas State University
Date of Publication, Distribution, etc.
1988
PHYSICAL DESCRIPTION
Specific Material Designation and Extent of Item
161
DISSERTATION (THESIS) NOTE
Dissertation or thesis details and type of degree
Ph.D.
Body granting the degree
Kansas State University
Text preceding or following the note
1988
SUMMARY OR ABSTRACT
Text of Note
This study was conducted to examine the influence of temperature, moisture, and nitrogen on tillering of sorghum (Sorghum bicolor (L.) Moench) and pearl millet (Pennisetum americanum (L.) Leeke.) during initial growth and regrowth. Flux required to maintain a tiller per plant was determined and the influence of temperature, moisture, and nitrogen on this flux requirement was evaluated. The varieties evaluated were 'Trudan 8' hybrid sudangrass, 'DeKalb SX-17' hybrid sorghum-sudangrass, 'RS 610' grain sorghum, 'Wray' sweet sorghum, and 'Gahi-3' pearl millet. Varieties differed for tiller number within temperatures. Temperature did not affect tillers per plant within varieties during initial growth. Trudan 8 and DeKalb SX-17 produced the most tillers at all moisture levels. Tillers per plant decreased as moisture stress increased except for Wray and RS 610. Tillers per plant increased with higher nitrogen rates up to 90 kg N ha. Tillers per plant were linearly related to the daily rate of dry matter accumulation under different temperatures, moisture levels, and nitrogen rates in all varieties. These results are consistent with the hypothesis that each tiller requires a minimum flux of assimilate to maintain growth. Greater tillering varieties required less assimilate to sustain a tiller than lower tillering varieties. Flux required to sustain a tiller increased with increasing temperature for Gahi-3, while sorghums were unaffected. Flux requirement per tiller increased as moisture level increased but was not influenced by added nitrogen. N-use efficiency decreased as N rates increased. Water-use efficiency increased as available moisture level increased. Generally, varieties producing more dry matter used N and water more efficiently. In chamber studies, we found variation between growth chambers. A split-plot analysis was appropriate and accounted for variation among growth chambers, but a randomized complete block analysis ignored this variation and gave misleading conclusions.