Development of Yellow Mosaic Virus Resistant Genotypes in Urdbean TNAU blackgram VBN 6: A high yielding blackgram variety with resistant to Mungbean Yellow Mosaic Virus

Received Date: Dec 18, 2019 / Accepted Date: Dec 30, 2019 / Published Date: Dec 31, 2019 Abstract The Blackgram culture VBG04-014 is a cross derivative of Vamban 1 x Vigna mungo var. silvestris 1 released as variety TNAU Blackgram VBN(Bg)6, it is maturing in 65-70 days and suited for cultivation under both rainfed and irrigated conditions. It has an average yield potential of 871 Kg per hectare. This culture is resistant to Yellow Mosaic Virus, Leaf Curl Virus and less damage of pod borer. It possesses desirable characters like high protein content (21.1%). Grains are medium sized with black in colour. It is recommended for cultivation in Tamil Nadu.


Introduction
Blackgram Vigna mungo (L.) popularly known as urdbean in India. It is most important pulse crop in India. The varietal development in blackgram is necessary to fulfill the demand of people. Even though India is the highest producer in the world still the production level is very low compare to the requirement. The most serious disease of blackgram is Mungbean Yellow Mosaic Virus. Sources of resistance to MYMV have been identified in wild progenitor (Vigna mungo var. silvestris) of urdbean and it was used in breeding Page: 181 www.raftpubs.com programmes to develop resistant varieties in urdbean [1,2]. The purpose of the study was to develop drought tolerant with yellow mosaic virus resistance. The objective of this programme was to develop mungbean yellow mosaic virus resistant variety since many of the available varieties were susceptible to MYMV disease which leads to heavy yield loss to the farmers. TNAU blackgram VBN 6 was developed and released as resistant variety against to MYMV with high yield potential to farming communities. The both parents of VBN 6 blackgram is different from VBN 7 blackgram variety. This variety having special feature is top podding nature after 50 per cent flowering of variety the pods are expose to top of the plants where as VBN 7 on par with the plant height or below the plants canopy.

Materials and Methods
Crossing programme was started during Rabi 2007 -2008 between cultivated type with wild. The cultigene Vigna mungo Vamban 1(susceptible) with wild gene Vigna mungo var. silvestris 1 wild type (resistant). The urdbean variety Vamban1 is wide adaptable variety is having a high yield potential with susceptible to yellow mosaic virus used as donor.

Plant materials
The experimental materials are male and female parents and derivatives of forwarded generations. Female parent is Vigna mungo Vamban 1 and male parent is Vigna mungo var. silvestris 1 and seven F1s plants were raised. Collected seeds from selected F1s plants raised as F2 and forward F3 generations and further generation.

Methods of Phenotyping of mapping population
In the field condition, the MYMV infection can be evaluated by infector row method as described by Selvi et al. [3], (2006). The test materials were scored after 80% of plants showed MYMV incidence. The 203 individuals and progenies in the F2 and F3generation respectively were scored for MYMV infection using 1-9 rating scale suggested by Singh et al.

Agro inoculation test
Agro inoculation study was conducted in the Centre for Plant Molecular Biology. Tamil Nadu Agricultural University, Coimbatore. The tandem viral constructs of MYMV, VA 221 (KA30 DNA A + KA22 DNA B) and VA 239 (KA30 DNA A + KA27 DNA B) mobilized in Agrobacterium tumefaciens strains Ach 5 and C 58 were collected from Madurai Kamaraj University, Madurai and used for further studies. Agroinoculation was done on surface sterilized overnight sprouted seeds of the parents VBG01-0014 and Vigna mungo var silvestris and F2 individuals. Agrobacterium tumefaciens strains harbouring the appropriate partial tandem repeat clone were grown to 1 Optical Density at 600 nm in 2 mL AB minimal medium pH 7.0 containing the antibiotics like streptomycin (150 mg L -1 ), spectinomycin (50 mg L -1 ) and tetracycline (5 mg L -1 ) at 28°C at 220 rpm. From this, 1 mL of the culture was taken to inoculate, another 50 mL of AB minimal medium (pH -7.0) containing the above-mentioned antibiotics and grown to 1 OD aL 600 nm at 28°C at 220 rpm. The culture was spinned at 4000 rpm for 10 min at 25°C. Cells obtained were re-suspended in 50 mL of AB minimal medium (pH -5.6) with 100 in acetosyringone (100 µrn). Seed coat of the sprouted seeds was removed by using forceps and pricked around the hypocotyl region and were immediately immersed in the appropriate culture of A. tumefaciens. After the overnight incubation, seeds were washed with distilled water and sown in pots containing autoclaved sand and vermiculite in the ratio of 1:1. Agroinoculated plants were maintained in a growth chamber at 25°C, 60-70% relative humidity and a photoperiod of 16/18h. The  Page: 183 www.raftpubs.com yield over the checks Vamban 4 and VBN (Bg)5 respectively. The above trials during kharif seasons, the culture has recorded the higher mean yield more than 1000 kg/ha over the check varieties in five districts viz., Villupuram, Karur, Namakkal, Sivagangai and Tiruvannamalai, with highest yield of 1525 kg/ha in Nalluranpatti of Karur district. Under rabi season, the performance was good in Erode and Villupuram with highest yield of 1348 kg/ha at Koliyanur of Villupuram district [6][7][8].    Page: 184 www.raftpubs.com  In the On-Farm Trials (22 Nos.) conducted at Pudukkottai and Ariyalur districts, the culture VBG04-014has recorded 942 kg/ha which is 16.87 and 12.54 per cent increased yield over checks Vamban 4 (806 kg/ha) and VBN(Bg)5 (837 kg/ha) respectively [6][7][8].

Results and Discussion
The Blackgram culture VBG04-014contains protein content of 21.1% as against 20.5 of VBN (Bg) 4 and 20.2 of VBN (Bg) 5 ( Table 7). The length, breadth and thickness of whole grain is maximum in the culture VBG04-014 and their distinct characters characters recorded in Table 8.