Distribution of Two Species of Begomoviruses Infecting Blackgram in Andhra Pradesh

Background: Yellow mosaic diseases of blackgram is caused by two species of begomoviruses (MYMV, MYMIV). It is known fact that certain varities which are resistant to one species are susceptible to another species when screened by agroinoculations. Hence data on distribution of DNA-A &B components of MYMV / MYMIV under field conditions were not available in Andhra Pradesh. Methods: In the present study total eighty yellow mosaic infected blackgram samples were colleted from seven districts of Andhra Pradesh during rabi and kharif 2016-17. The total DNA was isolated and detected for presence DNA-A and B components of MYMV/ MYMIV by PCR with specific primers. Samples which showed negative in normal PCR are further detected by RCA-PCR. Results: PCR results showed that out of 80 YMD infected blackgram samples tested from seven districts, positve results were otained in 50% samples for MYMV-A, 98.75% for MYMIV-A,and 90% for MYMV-B and none for MYMIV-B. However RCA-PCR detected MYMIV-B presence in all 7 samples (8.25%) collected from Guntur district, but none from other six districts. These results clearly shows that both species of begoviruses are present in Andhra Pradesh and MYMIV-A is predominant species in Andhra Pradesh as compared to MYMV-A. Hence germplasm and breedig material should be screened for both the species of begomovirses either under field or through agroinoculations to develop YMV resistant blackgram.