Identificação do género Striga em Angola. Combate de Striga asiatica em milho

• Author(s): Dovala, António Chicapa
• Date: 2014
• Persistent ID: http://hdl.handle.net/10400.5/7336
• Origin: Repositório da UTL
• Subject(s): Fabaceae; Tripsacum; intercropping; nitrogen; taxonomy
• Document Type: Doctoral thesis
• Language: Portuguese
• Advisor(s): Monteiro, Ana Maria da Silva; Duarte, Maria Cristina
• Contributor(s): Repositório da Universidade de Lisboa

Description

Doutoramento em Engenharia Agronómica - Instituto Superior de Agronomia

Striga asiatica is the major constraints in maize (Zea mays) production in Angola. Since S. asiatica seedbanks are long-lived, control strategies that affect the seeds emergence and parasitism are necessary. Low soil fertility, namely phosphorus and nitrogen amount, is another factor that directly affects maize yield. Hence, this study aimed to: i) identify Angola Striga specimenes from portuguese Herbaria and collected nowadays in field surveys; ii) elaborate a dichotomic key to identify Striga species; iii) genus Striga distribution; iv) find Striga asiatica management strategies in maize, e.g. addition of nitrogen, several Fabaceae and Tripsacum intercropping, and herbicide control (imazapyr seed coating resistant maize). Striga species identifieds: S. aequinoctialis, S. asiatica, S. bilabiata ssp. bilabiata, S. elegans, S. forbesii, S. gesnerioides, S. hermonthica, S. hirsuta, S. linearifolia e S. macrantha e S. strigosa (synon. S. angolensis). T. laxum duplicated S. asiatica emergency comparatively to the maize. Reductions in the S. asiatica emergence were achieved with nitrogen addition, legumes intercropping and imazapyr. Maize yield increased with all tested control methods. Imazapyr was effective in controlling S. asiatica and Tripsacum rapidly reduces Striga seed bank in the soil.