Abstract only

Bipolaris sorokiniana (Sacc.) Shoem,[perfect stage Cochliobolus sativus (Ito and Kurib.) Drechsler ex Dastur] which causes spot blotch disease is a serious pathogen in wheat and barley. The fungus is capable of producing non-host-specific toxin of sesquiterpenoid nature in liquid minimal media that is pathogenic on barley as well as other Poaceae hosts. Most of the toxins reported from B. sorokiniana are host non-specific. However, in barley this toxin produces early and late necrotic symptoms after its infiltration of in the leaves. Out of 1685 germplasm lines screened only 58 lines showed late necrosis. All the late necrotic lines showed lower AUDPC while the early necrotic lines were susceptible with higher AUDPC. Toxin related necrosis was significantly influenced by temperature. Higher temperature reduced the time of necrosis. However, the difference in days in early and late necrosis was same. Wide variations in AUDPC (200-700) and duration for necrosis were also recorded in the late necrosis lines. Many early necrotic lines were also identified that showed low AUDPC at par with the late necrotic lines. Genotypes with late necrosis (BCU 3618, 3617, 3707, 3839, 3919) were crossed with the early necrotic line RD 2503. All the five F1s were intermediate for the necrotic reaction with the toxin. The F2 generation segregated in 1:2:1 ratio suggesting single gene control for this trait. Our finding suggests that spot blotch susceptibility appear to be governed partly by late necrotic trait. Hence, late necrotic trait could be used to enhance resistance in barley.

Global Wheat Program

Text in English

INT2917

CIMMYT Staff Publications Collection