<div>Background: Urdbean&rsquo;s low productivity is largely due to its susceptibility against whitefly-transmitted mungbean yellow mosaic virus (MYMV) disease. The effect of Salicylic acid (SA) on MYMV disease resistance and its impact on seed yield under field conditions on diverse genotypes is largely unknown. Therefore, in present investigation, we have analysed the effect of SA on induction of antioxidant enzymes leading to MYMV resistance and enhanced seed yield in urdbean genotypes. 
 
Methods: Different concentrations of SA were sprayed on 3 week-old susceptible urdbean genotype (LBG 623) and induction of antioxidant enzymes was analysed. A pot experiment was conducted to see the effect of SA on initial induction of antioxidant enzymes maintained over long period of time in 39 urdbean genotypes. Under field conditions, the effect of SA treatment on MYMV disease resistance and seed yield was assessed. 
 
Result: Rise in antioxidant enzyme production was observed in SA treated urdbean plants challenged with MYMV. The field experiment revealed that exogenous SA application significantly reduced MYMV incidence and increased seed yield in all 39 urdbean genotypes tested. The ability to confer MYMV resistance along with the increase in seed yield suggests the incorporation of SA in effective MYMV management strategies in urdbean.</div>

Salicylic Acid Induced Resistance against Mungbean Yellow Mosaic Virus (MYMV) and Enhanced Seed Yield in Resistant and Susceptible Urdbean [Vigna mungo (L.) Heper] Genotypes

<div>Background: Mungbean Yellow Mosaic Virus is one of the major constraints in mungbean production. Knowledge of mode of inheritance and gene effects of MYMV resistance is very useful and effective for the development of genotypes resistant to disease or incorporation of resistance into the desirable promising genotypes whichlack of disease resistance.&nbsp; 
 
Methods: In order to estimate inheritance pattern of MYMV disease resistance in mungbean, the study was conducted in summer season (2019) under natural condition. Six generations such as Pl, P2, Fl, BC1, BC2 and F2 of six combinations [two resistant genotypes (7639 and 10266) and three susceptible genotypes (7621, 10257 and R-021018)] were studied inheritance pattern of resistance to MYMV in segregation population.&nbsp; 
 
Result: Based on the result from mode of inheritance pattern of MYMV resistance, it can be concluded that single recessive gene is controlled the resistance of MYMV and susceptible behavior indicated as dominant over resistant. Additive gene action was the major role for the selection of MYMV resistance. Some differences in the expression of gene contributing for MYMV resistance from others findings might be attributed due to the sources of resistant genotypes which have different nature of resistant gene used in this investigation.&nbsp;</div>

<div>Inheritance and Gene Effect of Resistance to Mungbean Yellow Mosaic Virus (MYMV) in Mungbean [Vigna radiata (L.) Wilczek]</div>

<div>Background: Mungbean yellow mosaic virus disease is the most devastating disease on Mungbean production. The virus is transmitted by whitefly and can cause yield losses from 75 to 100 per cent. The development of mungbean cultivars resistant to both virus and its vector is considered as one of the most desirable means of managing the disease as it is environmentally safe and highly efficient. The selection of resistant genotypes in conventional methods is complex and time consuming. Hence, the use of molecular markers linked with resistance genes is powerful as it hastens the breeding programmes. The current study was aimed to develop mapping population and to validate molecular markers associated with Mungbean yellow mosaic virus (MYMV). 
 
Methods: The present investigation was carried out with 260 F2 individuals that were derived from crossing DGGV-2 and IPM 2-14 during Kharif-2017 at Main Agril Research Station, UAS, Dharwad. Hybrid seeds of this cross were harvested individually and sown during rabi 2017 along with the two parents, as checks for distinguishing the true hybrids. Hybridity of F1s was confirmed through molecular marker analysis and the true F1s were selfed to raise the F2 generation. 
 
Result: Of the 24 previously reported simple sequence repeat markers used for detecting the polymorphism, two markers viz., CEDG305 and CEDG115 were found to be polymorphic between DGGV-2 and IPM-2-14. Two hundred and sixty F2 plants segregated in the ratio of 3 S:1 R (202 susceptible: 58 resistant) as phenotypic and 1: 2 :1 as genotypic ratio implying that single recessive gene controlled resistance. Single marker analysis revealed that the molecular markers CEDG305 and CEDG115 were associated with MYMV resistance with a phenotypic variance of 24.5 and 10.3 per cent respectively. &nbsp;</div>

<div>Development of Mapping Population and Validation of Molecular Markers Associated with MYMV Resistance in Mungbean</div>

<div style="text-align:justify">Background: The main cause for low yield in greengram is its susceptibility to Mungbean Yellow Mosaic Virus (MYMV) which is the most prevalent and destructive viral pathogen cause 85% yield lose. Inter specific hybridization between Vigna radiata and Vigna mungo could be an alternate approach to develop MYMV resistant genotypes in greengram which leads to additional source of creating variability for desirable attributes including yield, nutritional quality, biotic and abiotic stresses. 
 
Methods: The present investigation was carried out at National Pulses Research Centre (NPRC), Tamil Nadu Agricultural University, Vamban during 2016-2017. Interspecific hybridization has been effected between Vigna radiata var. VBN (Gg)2, VBN (Gg) 3 (as females) and Vigna mungo Var. Mash 114 (as male) during Summer 2016. The interspecific F1 hybrids, F2 and F3 populations were evaluated during Kharif 2016, Rabi 2016-17 and summer 2017 respectively. The F2 and F3 populations were evaluated for days to 1st flowering, days to maturity, plant height (cm), number of branches / plant, number of clusters / plant, number of pods / clusters, pod length (cm), number of seeds / pod, number of pods / plant, single plant yield (g.). The MYMV resistance has been confirmed under infector row method using CO 5 as susceptible check variety. Phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV), Heritability (h2) in broad sense, genetic advance as per cent of mean, Skewness and Kurtosis were estimated for yield and yield components. 
&nbsp; 
Result: Four true F1 plants were recovered in Vigna radiata var. VBN (Gg)2 x Vigna mungo Var. Mash 114 cross combination. The fertile F1 had the shallow lobbed leaf of Vigna radiata var. VBN (Gg)2 and black colour seed of Vigna mungo var. Mash 114 with pollen fertility of 42.0 per cent and crossability of 12.50%. Most interestingly all the four interspecific F1 plants were free from MYMV disease. In F2 generation, only one healthy plant was survived which had a pod, stem and branching behaviour of blackgram and greengram characters of lobbed leaf and green seed colour. In F3 generation, number of branches per plant, number of clusters per plant, number of pods per plant, pod length and seed yield per plant had high GCV, high PCV, high heritability coupled with high genetic advance as per cent of mean. Present study suggests that MYMV resistant cultivars of greengram can be explored through interspecific hybridization with Vigna mungo var. Mash 114 as a source of resistance and the hidden transgressive segregants can be recovered in F3 generation.</div>

<div style="text-align:justify">Interspecific Hybridization Between Vigna radiata and Vigna mungo Towards the Broadening of Genetic Base for MYMV Disease Resistance and Generating Variability</div>

<div>Background: Mungbean yellow mosaic virus (MYMV) is economically most important disease of greengram reducing grain yields by 20-70%. Whiteflies and thrips are the most important insect pests which transmit the viral diseases MYMV and LCV respectively. The host plant resistance to MYMV disease in greengram genotypes has a great importance. The morpho-physiological and biochemical traits play an important role in host plant resistance against MYMV disease through insect vector resistance. 
 
Methods: A field experiment was conducted during rabi 2017-18 and 2018-19 at RARS, Lam, Guntur in a randomized block design with eight greengram genotypes and replicated thrice under receding soil moisture condition. The experiment was conducted using eight greengram varieties (WGG 42, Pusa Vishal, LGG 607, LGG 630, LGG 601, LGG 610, LGG 460 and LGG 450) obtained from RARS Lam Guntur and the genotype LGG 450 was considered as a susceptible check. The estimation of sugars, phenols, tannins, trichome density and SCMR was done at vegetative and reproductive stages of crop growth. 
 
Result: A significant variation was observed among the varieties for all the traits observed at vegetative and reproductive growth stages during both rabi 2017-18 and 2018-19. The total sugar content of the greengram varieties varied from 25.55 to 47.32 mgg-1 FW; the leaf phenolic content values ranged from 12.09 to 26.83 mg g-1 FW&nbsp;and the tannins content of the dried leaf samples ranged from 0.020 to 0.055 mgg-1 DW. The Trichome density of the greengram varieties varied from 75 to 162/cm2 of leaf area and the SCMR values ranged from 35.12 to 58.67. Higher seed yield was recorded in the variety LGG 630 followed by WGG 42 and the lower seed yield was recorded in the variety LGG 450 during rabi 2017-18 and 2018-19. The MYMV resistant varieties showed relatively higher phenolic, tannins content and trichome density and lower total sugar content in the leaf. The total sugar content showed a significant negative correlation with the seed yield. The SCMR value was significantly lower in the susceptible varieties of greengram with higher disease scores.</div>

<div style="text-align:justify">Morpho-physiological and Biochemical Variability in Greengram [Vigna radiata (L.) Wilczek] Varieties for Mungbean Yellow Mosaic Virus (MYMV) Resistance under Natural Field Conditions</div>

<div>Background: Mungbean yellow mosaic virus (MYMV) disease is the most destructive disease in blackgram. Development of MYMV resistant varieties is one of the best possible solutions to avoid the yield reduction in blackgram. There are conflicting reports on the genetics of resistance to MYMV disease claiming that it is controlled by both dominant and recessive genes. Hence the present study was aimed to understand the inheritance pattern of the MYMV disease resistance in eight crosses of blackgram. 
 
Methods: Parents, F1 and F2 generation of eight cross combinations were raised during July - Sep, 2018 at National Pulses Research Centre, Tamil Nadu Agricultural University, Vamban, Tamil Nadu. An infector row of CO 5 was raised to intensify the MYMV disease pressure after every eight rows.&nbsp;Based on disease incidence on 60th day after sowing, two phenotypic classes were formed among F2 plants with the scales of (1 to 3) as resistant phenotype and (4 to 9) as susceptible phenotype. The goodness of fit to Mendelian segregation ratio for MYMV disease resistance in the segregating population was tested by Chi square test (Stansfield, 1991). 
 
Result: The MYMV disease incidence was tri-genically controlled with inhibitory gene action in four crosses viz., MDU 1 x Mash 114, CO5 x Mash 114, MDU 1 x VBN 6 and CO 5 x VBN 6. Complementary gene action with two genes was observed in four crosses viz., MDU 1 x Mash 1008, CO 5 x Mash 1008, MDU 1 x VBN 8 and CO 5 x VBN 8. Differences in number of genes were observed due to the presence of recessive inhibitory gene in both male and female parents of the crosses which had complementary gene action for MYMV disease. The putative gene symbols assigned for the six genotypes viz., S1S1S2S2ii (MDU 1 and CO 5), s1s1s2s2II (Mash 114 and VBN 6) and s1s1s2s2ii (Mash 1008 and VBN 8), respectively.&nbsp;</div>

<div>Inheritance Pattern of Mungbean Yellow Mosaic Virus (MYMV) Disease Resistance in Blackgram [Vigna mungo (L.) Hepper]</div>

<div style="text-align: justify;">The present investigation was conducted to study the nature of inheritance of MYMV among intra-specific crosses among three MYMV susceptible and five MYMV resistant genotypes of green gram. The molecular screening and hotspot evaluation is carried out in fifteen F1 progenies and 8 F2 families, respectively. The yellow mosaic-affected leaf samples gave positive results with MYMIV specific primer pairs YFP1/YRP1 and YFP2/YRP2 amplified fragments having size of 704bp and 648 bp, respectively. Coat protein gene sequence analysis revealed that the identified virus is homologous to MYMV. The inheritance study based on F2 data indicated the ratio of MYMV resistant plants and susceptible plants showed a good fit to expected 3:1 (Susceptible: Resistant) suggesting a typical monogenic recessive gene governing resistant reaction to MYMV besides resting the susceptibility from the susceptible parents.</div>

<div style="text-align: justify;">Genotypic Analysis for Retrieval of MYMV Resistant Progenies from Certain Crosses of Mungbean [Vigna radiata (L.) Wilczek]</div>

Background: Mung bean (Vigna radiata L.) is among the most significant edible legume crops and consumed in various parts of the world. Among different biotic factors, mungbean yellow mosaic virus (MYMV) affects this crop. The objective of the present investigation was to assess genetic variability among mungbean genotypes for MYMV resistance using simple sequence repeat markers.&nbsp; 
 
Methods: The present research was conducted to assess the genetic diversity among selected mungbean genotypes from field screening of 303 genotypes with an emphasis on resistance against MYMV. The field screening was done at Seed Breeding Farm, College of Agriculture, JNKVV, Jabalpur, Madhya Pradesh during summer 2022, kharif 2022 and summer 2023. Thirty SSR markers have been utilized to measure genetic variation among the 32 studied genotypes.&nbsp; 
 
Result: Marker MB-SSR033 stands out as the most informative locus with the greatest PIC and gene diversity value. The cluster analysis, classified the 32 genotypes into two major groups and maximum distance was noted between PDM 139 and IC 314523. The SSR markers CEDG293 (10.14%) and DMBSSR008 (9.11%) were found considerably linked to MYMV resistance. Harnessing multiple sources of resistance gives a good possibility to boost the resistance and production of mungbean cultivars.

Assessment of Genetic Diversity for MYMV Resistance in Mungbean [Vigna radiata (L.) Wilczek] using SSR Markers

Background: Limited genetic diversity in blackgram, stemming from its common ancestry with greengram, presents challenges in combating Mungbean Yellow Mosaic Virus (MYMV), leading to yield stagnation. To address this, genetic screening and selection of segregating generations in F2 are essential for refining resistance traits with enhancing productivity. 
 
Methods: A two-season experiment was conducted in Panpoli, Tamil Nadu, during the Kharif 2021 and Kharif 2022 in a randomized block design using, F2 seeds from specific crosses (MDU 1 &times; Mash 114 and ADT 3 &times; PU 31), along with F1 and parent plants. MYMV disease scores were recorded using the infector row method for all the genotypes studied. 
 
Result: The study unveiled a complex genetic basis of MYMV resistance in blackgram, characterized by di-genic dominant genes displaying duplicative dominance type of epistatic interaction. This complexity underscores the insufficiency of simple selection methods. Estimates of genetic variability for &ldquo;number of pods per plant&rdquo; exhibited high genetic advance and moderate heritability, indicating control by additive genes. Positive correlations were observed between plant height, number of clusters per plant and number of pods per plant with yield. Path analysis revealed that traits like number of seeds per pod, 100 seed weight and number of pods per plant directly and positively influenced yield, which exhibit minimal influence from MYMV. These traits offer crucial selection criteria for enhancing MYMV resistance in blackgram.

Unravelling the Genetic Complexity: Enhancing MYMV Resistance in Blackgram [Vigna mungo (L.) Hepper] Through Trait-based Selection

<div>Background: Greengram or mungbean is a diploid (2n=22) autogamous leguminous crop. The average global yield is low and stagnant over years in the entire tropical and subtropical Asia. Any improvement in the yield is hard, predominantly because of pest infestation and diseases. Viral diseases result in significant financial losses due to drop in seed yield and quality in many important crops including greengram. Mungbean yellow mosaic disease (MYMD) can lead to yield loss up to 85% in greengram in epidemic conditions. 
 
Methods: The present study was conducted at Department of Genetics and Plant Breeding, Faculty of Agriculture, Annamalai University during the period August-October 2020 in three crosses of greengram viz., PLM 506 x IC 76417, PLM 506 x IC 76381 and IC 398746 x IC 76417. The mean data of five basic generations viz., P1, P2, F1, F2 and F3 of three crosses were evaluated. Populations were screened for MYMV disease resistance by employing infector row method. Scaling test was done using the mean values of various generations for the characters. Significance of scale C suggested dominance x dominance (l) type of gene interaction, whereas the significance of scale D showed additive x additive (i) type of gene interaction. The significance of any of the scaling tests proposes inefficacy of simple additive-dominance model. Five genetic effects viz., mean effect (m), additive (d), dominance (h), additive x additive (i) and dominance x dominance (l) was estimated. 
 
Result: Hundred-seed weight showed additive-dominance model in the cross PLM 506 x IC 76417. The additive as well as additive x additive type of gene action were in control of number(s) of clusters per plant, percentage of disease infection and most of yield components in the cross PLM 506 x IC 76417. Hence, selection at a later generation is effective to improve these traits. Pod length was controlled by additive gene action in the cross PLM 506 x IC 76381, whereas percentage of disease infection showed additive-dominance model. The additive as well as additive x additive type of gene action were in control of plant height and most of yield components in the cross PLM 506 x IC 76381. In the case of other traits, epistatic model was evidenced. Hence, selection needs to be postponed to a later generation. Based on gene action, these crosses may be employed to evolve high yielding plants with MYMV disease resistance.</div>