Exploring distribution and genomic diversity of begomoviruses associated with yellow mosaic disease of legume crops from India, highlighting the dominance of mungbean yellow mosaic India virus.

Yellow mosaic disease (YMD) caused by several begomoviruses is one of the major constraints of over a dozen leguminous crops worldwide, particularly in Asian and Southeast Asian countries. The present study aimed to investigate the distribution, diversity and prevalence of begomoviruses associated with YMD in leguminous hosts in five agro-climatic zones of India, to assess the extent of their geographical presence and develop location and crop-specific distribution maps. One hundred and seventy-four leguminous plant samples were tested from 32 locations in India to detect YMD-causing viruses. Additionally, publicly available data were incorporated into this study to provide a comprehensive overview of their distribution in India. This resulted in 581 reports on the DNA-A component representing 119 locations, which were also utilized to depict the distribution of YMD-causing viruses on a map of India. In this study, 117 full-length DNA-A and 103 DNA-B components were successfully characterized, representing the detected mungbean yellow mosaic India virus (MYMIV), mungbean yellow mosaic virus (MYMV), and horsegram yellow mosaic virus in the collected samples. Phylogenetic analysis of isolates of these species showed no differentiation based on location in India. Diversity indices revealed the abundance (55.9%) and dominance (0.56) of MYMIV across 119 locations. These findings hold significant implications for legume researchers, offering insights into disease prevalence and geographic distribution. Furthermore, the distribution of YMD-causing viruses in different agro-climatic zones will help researchers in developing zone-specific YMD-resistant cultivars of the legume crops and would facilitate effective disease management options.

Multi-location evaluation of field pea in Indian climates: eco-phenological dynamics, crop-environment relationships, and identification of mega-environments.

Characterization of crop-growing environments in relation to crop's genotypic performance is crucial to harness positive genotype-by-environment interactions (GEI) in systematic breeding programs. Given that, the study aimed to delineate the impact of diverse environments on crop phenology and yield traits of dwarf-statured field pea, pinpointing location(s) favoring higher yield and distinctiveness within breeding lines. We tested twelve field pea breeding lines across twenty locations in India, covering Central Zone (CZ), North Western Plain Zone (NWPZ), North Eastern Plain Zone (NEPZ), and Northern Hill Zone (NHZ). Across these locations, maximum and minimum temperatures during flowering (TMAXF, TMINF) and reproductive period (TMAXRP, TMINRP) ranged 18.9-28.3, 3.3-18.0, 15.0-30.8, and 7.9-22.1oC, respectively. Meanwhile, notable variations in phenological and agronomic traits (coefficient of variation) were observed: flowering (31%), days to maturity (21%), reproductive period (18%), grain yield (48%), and 100-seed weight (18%). Combined ANOVA demonstrated an oversized impact of environment (81%) on yield, while genotype and GEI effects were 2% and 14%, respectively. The variables TMINF, TMINRP, and cumulative growing degree-day showed positive correlations with yield, while extended vegetative and maturity durations negatively influenced yield (p < 0.05). Additionally, linear mixed-models and PCA results explained that instability in crop phenology had significant influence on field pea yield. Seed weight was markedly varied within the locations (9.9-20.8 g) and both higher and lower seed weights were associated with lower yields (Optimal = 17.1 g). HA-GGE biplot-based on environment focus-scaling demonstrated three mega-environments and specific locations viz. Kota (CZ), SK Nagar (CZ), Raipur (CZ), Sehore (CZ), and Pantnagar (NWPZ) as the ideal testing-environments with high efficiency in selecting new genotypes with wider adaptability. The study findings highlight distinct impact of environments on crop phenology and agronomic traits of field pea (dwarf-type), hold substantial value in designing efficient field pea (dwarf-type) breeding program at mega-environment scale.

Development of High Yielding Fusarium Wilt Resistant Cultivar by Pyramiding of "Genes" Through Marker-Assisted Backcrossing in Chickpea (Cicer arietinum L.).

Pusa 391, a mega desi chickpea variety with medium maturity duration is extensively cultivated in the Central Zone of India. Of late, this variety has become susceptible to Fusarium wilt (FW), which has drastic impact on its yield. Presence of variability in the wilt causing pathogen, Fusarium oxysporum f.sp. ciceri (foc) across geographical locations necessitates the role of pyramiding for FW resistance for different races (foc 1,2,3,4 and 5). Subsequently, the introgression lines developed in Pusa 391 genetic background were subjected to foreground selection using three SSR markers (GA16, TA 27 and TA 96) while 48 SSR markers uniformly distributed on all chromosomes, were used for background selection to observe the recovery of recurrent parent genome (RPG). BC1F1 lines with 75-85% RPG recovery were used to generate BC2F1. The plants that showed more than 90% RPG recovery in BC2F1 were used for generating BC3F1. The plants that showed more than 96% RPG recovery were selected and selfed to generate BC3F3. Multi-location evaluation of advanced introgression lines (BC2F3) in six locations for grain yield (kg/ha), days to fifty percent flowering, days to maturity, 100 seed weight and disease incidence was done. In case of disease incidence, the genotype IL1 (BGM 20211) was highly resistant to FW in Junagarh, Indore, New Delhi, Badnapur and moderately resistant at Sehore and Nandyal. GGE biplot analysis revealed that IL1(BGM20211) was the most stable genotype at Junagadh, Sehore and Nandyal. GGE biplot analysis revealed that IL1(BGM 20211) and IL4(BGM 20212) were the top performers in yield and highly stable across six environments and were nominated for Advanced Varietal Trials (AVT) of AICRP (All India Coordinated Research Project on Chickpea) in 2018-19. BGM20211 and BGM 20212 recorded 29 and 28.5% average yield gain over the recurrent parent Pusa 391, in the AVT-1 and AVT-2 over five environments. Thus, BGM20211 was identified for release and notified as Pusa Manav/Pusa Chickpea 20211 for Madhya Pradesh, Gujarat and Maharashtra, Southern Rajasthan, Bundhelkhand region of Uttar Pradesh states by the Central Sub-Committees on Crop Standards, Notification and Release of Varieties of Agricultural Crops, Ministry of Agriculture and Farmers Welfare, Government of India, for commercial cultivation in India (Gazette notification number S.O.500 (E) dt. 29-1-2021).Such pyramided lines give resilience to multiple races of fusarium wilt with added yield advantage.

Harnessing the hidden allelic diversity of wild Cicer to accelerate genomics-assisted chickpea crop improvement.

Chickpea, commonly called Bengal gram or Garbanzo bean, faces a productivity crisis around the globe due to numerous biotic and abiotic stresses. The eroded genetic base of the cultivated Cicer gene pool is becoming a significant bottleneck in developing stress-resilient chickpea cultivars. In this scenario, the crop wild relatives (CWR) of chickpea, with the useful genomic wealth of their wild adaptation, give a ray of hope to improve the genetic background of the cultivated Cicer gene pool. To extrapolate these unearthed genomic diversities of wild, we require a thorough understanding of the pre-historic domestication episodes that are changing their shape with the expansion of the available scientific evidence. Keeping aforesaid in view, the current review article provides a glimpsed overview on several efforts done so far to reveal the mysterious origin and evolution of the Cicer gene pool, along with the constraints in their utilization for chickpea crop improvement. It encapsulates various stress-resilient CWR of chickpea and their use in several pre-breeding programs to develop numerous breeding populations for crop genetic enhancement. Further, this review will recapitulate the significant contributions of structural, functional and comparative genomics, pan-genomics and diverse genomics-assisted breeding strategy in dissecting the untapped trait-specific allelic/gene diversity and domestication pattern behind the CWR of chickpea, along with their potential and promises. We expect the newly explored genetic variations may be used in the breeding programs for re-wilding the cultigens' genomic background to open a new avenue for genetic gain and crop improvement capacity of chickpea.

Resequencing of 429 chickpea accessions from 45 countries provides insights into genome diversity, domestication and agronomic traits.

We report a map of 4.97 million single-nucleotide polymorphisms of the chickpea from whole-genome resequencing of 429 lines sampled from 45 countries. We identified 122 candidate regions with 204 genes under selection during chickpea breeding. Our data suggest the Eastern Mediterranean as the primary center of origin and migration route of chickpea from the Mediterranean/Fertile Crescent to Central Asia, and probably in parallel from Central Asia to East Africa (Ethiopia) and South Asia (India). Genome-wide association studies identified 262 markers and several candidate genes for 13 traits. Our study establishes a foundation for large-scale characterization of germplasm and population genomics, and a resource for trait dissection, accelerating genetic gains in future chickpea breeding.

Genetic variability for iron and zinc as well as antinutrients affecting bioavailability in black gram (Vigna mungo (L.) Hepper).

The mineral content of pulses is generally high, but the bioavailability is poor due to the presence of phytate and polyphenols which inhibits Fe absorption. In the present study, the genetic variability and heritability for seed Fe and Zn content was studied. The effect of genotypes was significant for all the quality traits indicating presence of enough variability among the blackgram genotypes for the traits. The Fe content in 26 blackgram genotypes ranged from 71.02 to 100.20 ppm, whereas Zn content ranged from 18.93 to 60.58 ppm. Maximum Fe as well as Zn was recorded in genotype SHEKHAR 2 (100.2 and 60.58 ppm respectively). The Phytic acid and polyphenol content among genotypes varied significantly and it ranged from 0.06-0.37% to 5.88-9.03 mg/g, respectively. High phytic acid content was recorded in black gram genotypes COBG 653, Nodai Urd, NP 03 and PKG U 03, whereas high polyphenol content was recorded in PU 31, IPU 99-200, PDU 1 and YAKUBPUR 2. Blackgram genotype COBG 653 had high phytic acid but low polyphenol content. The genotype × year interaction was significant for all the traits under study which indicates differential reaction to the expression of quality characters over years. Fe content in blackgram genotypes showed significant positive phenotypic correlation with Zn content while at genotypic level in addition to Zn, it showed positive correlation with phytic acid and polyphenol content as well. This indicates that although the traits are genotypically correlated, the expression is masked by the environmental influence. This is further exhibited from low heritability estimates for phytic acid and polyphenol content among the genotypes.

Gene interactions and genetics for yield and its attributes in grass pea (Lathyrus sativus L.).

Grain yield is a complex character representing a multiplicative end product of many yield attributes. However, understanding the genetics and inheritance that underlies yield and its component characters pose a prerequisite to attain the actual yield potential of any crop species. The knowledge pertaining to gene actions and interactions is likely to direct and strengthen the crop breeding programmes. With this objective, the present investigation was undertaken by using six generations derived from three different crosses in grass pea. The study underscores the significance of additive-dominance model, gene action involved in inheritance of quantitative characters and heritability. Of note, nonallelic interactions influencing the traits were detected by both scaling test and joint scaling test, indicating the inadequacy of the additive-dominance model alone in explaining the manifestation of complex traits such as yield. Besides, additive (d) and dominance (h) gene effects, different types of interallelic interactions (i, j, l) contributed towards the inheritance of traits in the given crosses. Nevertheless, predominance of additive variance suggests a difference between homozygotes at a locus with positive and negative alleles being distributed between the parents. Duplicate epistasis was prevalent in most of the cases for traits like plant height, seeds/pod, 100-seed weight and pod width. In view of the diverse gene actions, i.e. additive, dominant and epistasis, playing important roles in the manifestation of complex traits like yield, we advocate implementation of population improvement techniques in particular reciprocal recurrent selection to improve productivity gains in grass pea.

Identification and detection of genetic relatedness among important varieties of pea (Pisum sativum L.) grown in India.

Among the cool season legume crops grown in India and the Indian sub-continent, peas are very popular and preferred by the growers as well as consumers for various uses. The third largest area in pea cultivation is occupied by India after Canada and Russia. Among the important and popular varieties of peas that are grown in India, several are from exotic background. But very little work has been done to carry out the genetic diversity present in the widely adapted Indian pea varieties using DNA markers. Twenty-four most popular and widely adapted varieties were subjected to RAPD analysis to find out the genetic relatedness among them using 60 decamer primers. All the primers used in our study were found to be polymorphic and seven of them showed 100% polymorphism. Out of 579 amplified products, 433 showed polymorphism (74.8%). On an average, 9.65 bands were amplified per primer. Cluster analysis based on Jaccard's similarity coefficient using UPGMA grouped all the tall type varieties together, whereas, dwarf types formed two different clusters based upon their pedigree. The arithmetic mean heterozygosity (Hav) value and marker index (MI) was found to be 0.496 and 4.787, respectively, thus this indicated the efficiency of RAPD as a marker system. Moreover, the calculated value of probability of identical match by chance suggested that about 10(53) genotypes can be unambiguously distinguish by employing 60 RAPD primers.