HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Peterson, G. C. Articles by Schaefer, K. Search for Related Content PubMed Articles by Peterson, G. C. Articles by Schaefer, K. Agricola Articles by Peterson, G. C. Articles by Schaefer, K.

Grain Sorghum Resistance to Midge by Yield Loss vs. Visual Scores

Texas Agric. Exp. Stn., Rt. 3 Box 219, Lubbock, TX 79401-9757
Agric. Res. Corp., Abu Naama, Sudan
Dep. of Entomology, Texas A&M Univ., College Station, TX 77843
Texas Agric. Exp. Stn., Highway 44, Rt. 2, P.O. Box 589, Corpus Christi, TX 78410

^* Corresponding author.

Biology of the sorghum midge, Contarinia sorghicolà (Coquillett), necessitates testing of sorghum, Sorghum bicolor (L.) Moench, cultivars in field plots in multiple locations and/or years to identify resistant genotypes. Using converted exotic sorghum cultivars, this study was conducted to compare visual damage scores across locations and years vs. indirect resistance measurements (percentage yield loss and number of midge per panicle) in a single location and year with two planting dates. Visual damage ratings were made at physiological maturity on the percentage of blasted kernels per panicle in replicated, randomized-complete-block field experiments at three locations in 1983 through 1985. In 1985, indirect measurements and visual damage ratings were made at one location. A significant positive relationship was found between visual midge damage rating and percentage yield loss (r = 0.347), and between visual midge damage rating and midge number (r = 0.220). Percentage yield loss did not increase the reliability of identification of resistant cultivars. Cultivars identified with resistance by both methods were IS8232C, IS8237C, IS8112C, IS2740C, IS3390C, IS7132C, IS2685C, IS957C, IS7193C, IS2144C, and IS12572C. The correlation between percentage yield loss and midge number (r = 0.090) was nonsignificant. Both methods depend on high midge density to differentiate resistant and susceptible genotypes. When midge were not abundant good differentiation was not obtained. Indirect resistance measurements were more time consuming than a single visual rating at maturity, and when multiple years or locations were required, the visual damage rating was a more effective method of germplasm evaluation.

Received for publication August 29, 1988.