Phenotypic Diversity in Pre- and Post-Attachment Resistance to in a Core Collection of Rice Germplasms.

In sub-Saharan Africa, upland rice cultivation is expanding into rainfed areas endemic to the root parasitic weed Striga hermonthica. We evaluated the Striga resistance of 69 accessions from the World Rice Core Collection (WRC) to estimate the phenotypic diversity within the Oryza sativa species. Pre-attachment resistance was screened based on the germination-inducing activities of the root exudates, while post-attachment resistance was screened through rhizotron evaluation.

Germination stimulatory activity of bacterial butenolide hormones from J1074 on seeds of the root parasitic weed .

Damage caused by Orobanchaceae root parasitic weeds is a substantial agricultural problem for global food security. Many studies have been conducted to establish practical methods of control, but efforts are still required for successful management. Seed germination of root parasitic weeds requires host-derived germination stimulants including strigolactones (SLs).

How does Bewitch its hosts?

The common name witchweed synonymous with the Latin name befits the bewitching effects, wilting and chlorosis, the parasite inflicts on its hosts long before it emerges and becomes visible above the ground. However, interactions in the rhizosphere between host roots and seedlings are concealed and inscrutable. In vitro experiments revealed that abscisic acid was produced by seedlings and a considerable portion of the phytohormone was exuded.

Aberrant protein phosphatase 2C leads to abscisic acid insensitivity and high transpiration in parasitic Striga.

Striga parasitizes major crops in arid regions, depriving the host crop of nutrients through the transpiration stream and causing vast agricultural damage. Here, we report on the mechanism underlying how Striga maintains high transpiration under drought conditions. We found that Striga did not respond to abscisic acid, the phytohormone responsible for controlling stomatal closure.

Identification of Striga hermonthica-Resistant Upland Rice Varieties in Sudan and Their Resistance Phenotypes.

Rice has become a major staple cereal in sub-Saharan Africa. Currently, upland rice cultivation is expanding particularly in rainfed areas where the root parasitic weed Striga hermonthica, a major constraint to cereal production, is endemic. Laboratory, pot, and semi-controlled open air experiments were performed to evaluate resistance of selected rice varieties in Sudan to a resident S.