Research Projects

Pigeon pea ( Cajanus cajan) is an important drought resistant legume food crop mainly used as dhal and as green vegetable. The crop occupies about 2.31 lac ha. in Andhra Pradesh with production of 83,992MT. The crop is affected by many diseases, among them Fusarium wilt and sterility mosaic disease are major constraints in productivity in AP, for which resistant genotypes are available. Yellow mosaic disease (YMD) of pigeonpea caused by begomovirus is minor importance due to low incidence of disease ranging from 1-6% in Karnataka, Chhattisgarh and Andhra Pradesh sates . However during kharif 2021 at KVK farm , Reddipalli and other isolated places in Anathapur district of Andhra Pradesh , we noticed upto 80% incidence . Affected plants shows typical bright yellow mosaic symptoms with stunting of the plants at 30 DAs . Due to climate change , the diseases which is minor once is becoming major problem and in absence of resistant genotypes , farmers may incur huge losses. This disease is caused by three species of begomoviruses (MYMV, HgYMV, ToLCV) in different states but the begomovirus species associated with out break of YMD at KVK farm was not known. The information on which species of begomoviruses is associated with outbreak of diseases in KVK farm and elsewhere in state is lacking, except preliminary reporting of HgYMV with YMD samples collected from Tirupati based on PCR amplification (Chaitanya et al., 2022) . The resistance sources for this disease were not identified so far and hence there is urgent need to identify resistant sources so that resistant genotypes can be developed by the breeders .No information is available on what kind symptoms each species of begomovirus produce either alone or in combination. since the virus is transmitted by whitefly and survive on many weed hosts , there is a possibility for increase in disease incidence in future under favorable climatic conditions. Keeping in view the future threat to pigeonpea productivity in state and elsewhere , there is need to study begomovirus species associated with disease, kind of symptoms each begomovirus species produce on pigeonpea, genetic variability in virus, and to identify resistant sources through agroinoculation /field screening.