Asmita Sirari

Detection of quantitative trait loci for mungbean yellow mosaic India virus (MYMIV) resistance in mungbean (Vigna radiata (L.) Wilczek) in India and Pakistan

Yellow mosaic disease (YMD) is one of the major diseases affecting mungbean (Vigna radiata (L.) Wilczek). In this study, we report the mapping of the quantitative trait locus (QTL) for mungbean yellow mosaic India virus (MYMIV) resistance in mungbean. An F8 recombinant inbred line (RIL) mapping population was generated in Thailand from a cross between NM10-12-1 (MYMIV resistance) and KPS2 (MYMIV susceptible). One hundred and twenty-two RILs and their parents were evaluated for MYMIV resistance in infested fields in India and Pakistan. A genetic linkage map was developed for the RIL population using simple sequence repeat (SSR) markers. Composite interval mapping identified five QTLs for MYMIV resistance: three QTLs for India (qYMIV1, qYMIV2 and qYMIV3) and two QTLs for Pakistan (qYMIV4 and qYMIV5). qYMIV1, qYMIV2, qYMIV3, qYMIV4 and qYMIV5 explained 9.33%, 10.61%, 12.55%, 21.93% and 6.24% of variation in disease responses, respectively. qYMIV1 and qYMIV4 appeared to be the same locus and were common to a major QTL for MYMIV resistance in India identified previously using a different resistant mungbean.

Evaluation and molecular characterization of advanced interspecific lines for genetic improvement in mungbean [Vigna radiata (L.) Wilczek]

The present study was undertaken to evaluate advanced interspecific lines of mungbean [Vigna radiata (L.) Wilczek] for yield and its components and to understand genetic diversity among these lines using microsatellite markers (SSRs). The experimental material consisted of 51 advanced interspecific lines developed from mungbean [Vigna radiata (L.) Wilczek] ×urdbean [Vigna mungo L. Hepper] and mungbean [Vigna radiata (L.) Wilczek] ×ricebean [Vigna umbellata Thumb.] crosses and 13 parental lines (mungbean, urdbean and ricebean). A wide range of variability was observed for eleven yield and its component characters and many superior lines were identified. SSR markers synthesised from different Vigna species were used to assess genetic diversity in advanced interspecific lines along with their parents. The interspecific lines were converged into three main clusters while the parental lines were converged into three main and four sub clusters, depicting genetic diversity among them.

Identifying environmental factors impacting yellow mosaic virus disease of green gram (Vigna radiata L.) Wilczek

The relationship between environmental factors and the incidence of yellow mosaic virus disease in green gram was studied for the period of 23 years using historical data on disease index (DI) and environmental factors from 1985 to 2007. The environmental factors showed consistently significant correlations with DI during the 29th–33rd standard meteorological week (SMW) periods and the same period was taken for further analysis. Among the environmental factors, maximum temperature was highly positively correlated (r = 0.63), followed by sunshine hours in SMW 29 (r = 0.48), with the disease. However, rainfall during SMW 30–33 (r = −0.38) and evening relative humidity during SMW 29–33 (r = −0.42) were negatively correlated with disease. As these four environmental factors contribute mainly to disease, same were used to develop the functional models by conducting multiple regression analysis for the period SMW 29–33. Among these, linear model gave highest R2 value (0.47) and this model was validated for the periods 2008–2010 and the predicted estimates were in full agreement with the observed estimates (R2 = 0.874).

Understanding syntonic relationship of foliar diseases of green gram with weather variables

Green gram with good adaptation to various eco-regions is extensively grown in India and other south Asian countries. Biotic stresses of viral, bacterial or fungal nature appear as major limiting factors which may occur singly, simultaneously, in combinations or in sequence in various eco-geographical zones. Weather variables have profound impacts on the disease occurrence, the interactions between weather variables and diseases based on long term data-sets, which can be used to point out the critical variables and the sensitive period in crop season for management practices. Good correlation was observed from 27 to 36th meteorological week (second week of July–first week of September) for the diseases such as bacterial leaf spot (BLS), Cercospora leaf spots (CLSs), Anthracnose (RLS) and weather variables. A close relationship of RF and RHe appeared with RLS, RHm, RHe and Tmin showed close relationship with BLS, whereas Tmax, SSh and RF showed a close relationship with CLS.

Status of resistance to Ascochyta blight and Fusarium wilt in large-seeded kabuli

Of the 390 Kabuli chickpea genotypes evaluated from 2005 to 2010 against Ascochyta blight (AB), Fusarium wilt (FW) and Dry root rot (DRR) resistance using standard screening techniques, 48 were found to be resistant to FW and DRR. Of these, four genotypes viz GLK95091, GLK95061, GLK24092 and GLK24096 showed resistance to AB with disease score less than 4.0 while another four genotypes GLK22072, GLK22098 and GLK24099 displayed AB disease score 5.0. GLK 22117 with FW percentage 6.3 and DRR 3.5 tested for seven years displayed good performance at other locations in India as well. Extra bold seeded genotypes GLK 26171, GLK26177 and GLK23001have shown good level of resistance to AB, FW and DRR and can be suggested as donors in crossing programme. It was observed that level of FW resistance was comparatively low in large-seeded and extra-large-seeded kabuli than small seeded kabuli.