Zakir Hussain

Biological control agents are preferred over chemicals for managing plant diseases, with Trichoderma species being particularly effective against soil-borne pathogens. This study examines the use of a highly antagonistic strain, Trichoderma asperellum A10, and a virulent strain, Sclerotium rolfsii Sr38, identified and confirmed through ITS, β-tubulin (T. asperellum), TEF 1α, and RPB2 (S. rolfsii) sequences. In vitro and in planta experiments compared the antagonistic potential of A10 with other antagonistic fungi and fungicides against S. rolfsii. A10 achieved 94.66% inhibition of S. rolfsii in dual culture assays. In greenhouse trials with tomato variety Pusa Ruby, A10 showed significant pre- and post-inoculation effectiveness, with disease inhibition of 86.17 and 80.60%, respectively, outperforming T. harzianum, Propiconazole, and Carbendazim. Additionally, microbial priming with A10 was explored to enhance plant defense responses. Pre-treatment of tomato plants with T. asperellum A10 led to significant upregulation of several defense-related genes, including PR1, PR2, PR3, PR5, PR12, thioredoxin peroxidase, catalase, polyphenol oxidase, phenylalanine ammonia lyase, isochorismate synthase, laccase, prosystemin, multicystatin, WRKY31, MYC2, lipoxygenase A, lipoxygenase C, proteinase inhibitor I, proteinase inhibitor II, and ethylene response 1 associated with various signaling pathways such as salicylic acid (SA)-mediated and jasmonic acid/ethylene (JA/ET)-mediated responses. This upregulation was particularly evident at 48 h post-inoculation in A10-primed plants challenged with S. rolfsii, inducing resistance against collar rot disease. This study underscores the effectiveness of T. asperellum A10 in controlling collar rot and highlights its potential for inducing resistance in plants through microbial priming, providing valuable insights into sustainable disease management strategies.

Bio-control agents are the best alternative to chemicals for the successful management of plant diseases. Among them, Trichoderma is commonly used as a biological control agent in plant disease management due to its ability to suppress soil-borne plant pathogens. In the present study, 20 Trichoderma asperellum isolates were collected from different geographical locations and confirmed using morphological characteristics and molecular phylogenetic inferences based on combined ITS and β-tubulin sequences. All twenty isolates were screened for their antagonism against the collar rot pathogen under in vitro and in planta conditions. The isolates were evaluated through dual culture and volatile methods in an in vitro study. Isolate A10 inhibited the test pathogen Agroathelia rolfsii at 94.66% in a dual culture assay and 70.95% in a volatile assay, followed by the isolates A11 and A17, which recorded 82.64% and 81.19% in dual culture assay and 63.75% and 68.27% in the volatile assay respectively. An in planta study was conducted under greenhouse conditions in tomato var. pusa ruby by pre- and post-inoculation of T. asperellum isolates in the A. rolfsii infected soil to evaluate their antagonistic potential against the disease. The A10 isolate was found effective under both pre- and post-inoculation conditions, with a disease inhibition percent of 86.17 and 80.60, respectively, followed by the isolates A11 and A17, which exhibited inhibition of 77.80% and 75.00% in pre-inoculation and 72.22% and 69.44% in post-inoculation, respectively. Further, biochemical analysis was conducted to determine the specific activity of hydrolytic enzymes produced by T. asperellum during interaction with A. rolfsii. We found that isolate A10 produces more hydrolytic enzymes with the specific activity of 174.68 IU/mg of β-1,3 glucanase, 183.48 IU/mg of β-1, 4 glucanase, 106.06 IU/mg of protease, followed by isolate A17, A11 respectively. In GC-MS analysis, we observed maximum anti-microbial volatile organic compounds from the isolate A10, including 2H-Pyran-2-one (17.39%), which was found to be most abundant, followed by dienolactone (8.43%), α-pyrone (2.19%), and harziandione (0.24%) respective retention time of 33.48, 33.85, 33.39, and 64.23 min, respectively, compared to other isolates. In the TLC assay, we observed that a greater number of bands were produced by the A10 and A17 isolates in the Hexane: Ethyl Acetate (1:1) solvent system than in the 9:1 solvent system, which represents the presence of major metabolites in the ethyl acetate extract.

Amaranth and buckwheat are two pseudo-cereals preferred for their high nutritional value, are gluten free and carry religious importance as fasting food. Germplasm resources are the reservoir of diversity for different traits, including nutritional characteristics. These resources must be evaluated to utilize their potential in crop improvement programs. However, conventional methods are labor-, cost- and time-intensive and prone to handling errors when applied to large samples. NIRS-based machine learning to predict different nutritional traits is applied in different food crops for multiple traits. NIRS prediction models are developed in this study using the mPLS regression technique for oil, protein, fatty acids and essential amino acid estimation in amaranth and buckwheat. Good RSQ external (power of determination) values were obtained for the above traits ranging from 0.72 to 0.929. Ratio performance deviation (RPD) value for most of the traits ranged between 2 and 3, except for valine (1.88) and methionine (3.55), indicating good prediction capabilities in the developed model. These prediction models were utilized in screening the germplasm of amaranth and buckwheat; the results obtained were in good agreement and confirmed the applicability of developed models. It will enable the identification of a trait-specific germplasm as a potential gene source and aid in crop improvement programs.

Thepresence of tubercles and pattern of ridges (continuous vs discontinuous) are important traits of bitter gourd which determine market price in India.The tuberculate fruits with broken or discontinuous ridges have more unit price than the non-tuberculate and continuous ridged fruits. In the present study, two different botanical varieties of Momordica charantia var. charantia (DBGS-2 and DBGS-54) and M. charantia var. muricata (DBGS-34) were used for inheritance study and molecular tagging of fruit tubercles and fruit ridgeness pattern. The findings revealed the monogenic control for both the traits. The bi-parental mapping populations (F2) were developed from the crosses DBGS-54×DBGS-34 and DBGS-2×DBGS- 34 for tagging of tuberculate (Tb) and continues ridgeness (cr) locus, using SSR markers. The single plant analysis of F2 population (derived from DBGS-54×DBGS-34) based on SSR markers found McSSR-20 was linked to fruit tubercles gene (Tb) at 12.50 cM and another SSR marker JY004 in the cross DBGS-2×DBGS-34 was found linked with fruit ridgeness pattern (cr) gene at a distance of 19.6cM. It is the first report of SSR markers linked to fruit tubercles and ridgeness which will be helpful further in fine mapping of these traits with more PCR based markers. These findings will help in differenciating the genotypes with tubercles and pattern of ridgeness at the early stage of the crop and can be used in accelerating trait specific breeding programme in bitter gourd.

An experiment was carried out with 5 parent and 3 hybrid papaya genotypes to study the genetic variabilityand correlation between different yield attributing traits by evaluating 16 vegetative, reproductive, and fruit yieldcontributing traits during 2016–2017. The findings indicate that the maximum fruiting zone (129.8 cm) was in PS3 followed by PS 3 × P-7-9 (128 cm). The hybrid PS 3 × P-7-9 had maximum number of fruits per plant (44.67), minimum fruit weight (1020g) and maximum yield per plant (46.33 kg/plant) among the three hybrids evaluated. The phenotypic coefficient of variation (PCV) is higher than the genotypic coefficient of variation (GCV) for allthe traits studied. The genotypic variance and phenotypic variance were high for traits like leaf width, stemdiameter and fruit weight. Traits such as leaf length, petiole length, number of fruits per plant, fruit diameterand fruit yield exhibited higher value of GCV and PCV. Heritability for traits ranged from 53.83 to 99.49, of whichmajority of traits showed very high heritability, except some traits such as inflorescence size and fruit lengthwhich showed moderate heritability. Genetic advance (GA) was recorded highest for fruit length (179.13). Traitslike fruit yield, petiole length and leaf length exhibited high heritability accompanied by high to moderate geneticadvance indicating additive gene action, which suggest that selection may be effective for these traits. The trait, fruit yield was positively associated with plant height at flower initiation and maturity stage, stem diameter, daysto flowering, fruiting zone, number of fruits per plant and fruit diameter.