Identification and Confirmation of Resistance in Mungbean [Vigna radiata (L.) Wilczek] Derivatives to Mungbean Yellow Mosaic Virus (MYMV)

Background: Mung bean Yellow Mosaic Virus (MYMV) is found to be one of the prime viral diseases of mungbean in Tamil Nadu state. Screening for MYMV resistance in field condition always remains a hassle for breeding society. The peculiar MYMV symptoms often failed in the field due to some factors such as environmental changes, whitefly genotypes, host factors etc. With the above perspective, the present study aimed to screen the mung bean derivatives against MYMV through a novel in vitro agroinoculation technique and further substantiation through whitefly transmission.Methods: Four interspecific derivatives (VGGRU 1, VGGRU 2, VGGRU 3 and VGGRU 4) generated by making crosses between mungbean VRM (Gg) 1 and rice bean (TNAU RED) along with the susceptible check VRM (Gg) 1 were agroinoculated with the MYMV infectious clone VA 239 (KA30 DNA A + KA27 DNA) and are further substantiated through whitefly transmission studies from the artificially reared whiteflies. Result: The agroinoculation results revealed that among the four interspecific derivatives, VGGRU 1 was found to be completely resistant to MYMV. The substantiation of the obtained result through whitefly transmission also revealed that 24 h Acquisition Access Period (AAP) and 24 h Inoculation Access Period (IAP) with Bemisia tabaci able to cause 65% infectivity in susceptible plant VRM (Gg) 1 and zero infectivity in VGGRU 1 and the results were PCR confirmed for the presence of viral DNA.

Deployment of yellow mosaic disease resistance in mungbean [Vigna radiata (L.) Wilczek] through interspecific hybridization

Mungbean yellow mosaic virus [Urdbean: New Delhi: 2011] Accession no. JQ398669.1, was found to be prevalent in both summer and kharif season causing Yellow Mosaic Disease (YMD) of mungbean. Since similar strain was observed in both the seasons, the short duration interspecific derivative lines of mungbean suitable for summer season were evaluated for YMD resistance in kharif season- a highly favourable environment for YMD epidemics during 2014-2016. Out of fourteen lines showing stable resistant reaction, few lines promising for other economically important traits were selected and again evaluated by whitefly mediated artificial inoculation technique for confirmation of resistance during 2017. The selected promising interspecific derivative lines showed no YMD symptoms except SML 1829. SML 1827 derived from interspecific cross between mungbean and rice bean showed highest yield among all interspecific derivatives. Further, rice bean specific segments were also identified in SML 1827 with SSR markers.