Root development and production of a witchweed (Striga spp.) germination stimulant in sorghum (Sorghum bicolor) cultivars

• Published in: Weed science Vol. 40
• Main Authors: Oliver A, Leroux G.D
• Format: Journal Article
• Language: English
• Published: 01.12.1992
• Subjects: estimulo; exsudat; exudados; exudates; germinacion; germination; host parasite relations; parasitic plants; pest resistance; plantas parasitas; plante parasite; racine; raices; relaciones huesped parasito; relation hote parasite; resistance aux organismes nuisibles; resistencia a las plagas; root systems; roots; sistema radicular; sorghum bicolor; stimuli; stimulus; striga asiatica; striga hermonthica; systeme racinaire; variedades; variete; varieties
• ISSN: 0043-1745; 1550-2759
• DOI: 10.1017/S0043174500058100

Sorghum cultivars were compared for their root development and production of the witchweed germination stimulant sorgoleone. In pot experiments, the resistant cultivar IS-7777 yielded a greater root biomass and root length, but a smaller root length/biomass ratio than the highly susceptible cultivars CK-60B and Bimbiri. Seedlings of these latter two cultivars exuded a high concentration of sorgoleone, while the low-susceptible cultivar IS-14825 exhibited a low production of this compound. In contrast, the low-susceptible cultivar Seguetana Niarabougou exhibited a high production of sorgoleone, while the resistant cultivars IS-7777 and Framida exuded a moderate amount of this compound. These results indicate that witchweed seed avoidance by means of reduced root growth is unlikely to be an important factor involved in the resistance of IS-7777. Low production of sorgoleone could partly explain low susceptibility of IS-14825, but other compounds may play a more significant role in the stimulation of witchweed germination.